Lá Szló

Zsolt Garamszegi

Juan José

Soler Cruz

Martine Fournier

Nathalie Lecat

Georges Audi

Laurence Peyraud

Keywords: birds, dilution effect, fear-response, FID, gregariousness, human disturbance, social interactions, vigilance

A general introduction in English provides general scientific background, summary and conclusions, and it brings the manuscripts together in a common context.

The interactions between predator and prey represent one of the most substantial events in nature and pose important questions for most creatures dealing with one or more likely predators. To cope with the pressure of predation and survive, prey have evolved many sequential protective measures and complex anti-predator strategies. Numerous antipredator behavior metrics have evolved to partly reduce the risk of predation, such as mimicry, clustering in groups, alarm calls, warning signals and escape behavior (Caro, 2005), and the origin and the maintenance of this diversity begs an explanation.

i Plumage coloration Prey can avoid predation by concealing themselves in the environment so that predators would fail to find them. Many studies have addressed anti-predator benefits of cryptic plumage in adults [START_REF] Götmark | Anti-predator effect of conspicuous plumage in a male bird[END_REF][START_REF] Götmark | Bright male plumage and predation risk in passerine birds: Are males easier to detect than females?[END_REF][START_REF] Slagsvold | Predation favours cryptic coloration in breeding male pied flycatchers[END_REF], and predation is a selective force partially because of the potential benefits of plumage coloration (e.g. [START_REF] Caldwell | Predation as a selective force on foraging herons: Effects of plumage color and flocking[END_REF]. In some species, individuals change color across seasons (e.g. [START_REF] Slagsvold | Variation in plumage colour of the great tit Parus major in relation to habitat, season and food[END_REF][START_REF] Steen | Cryptic behaviour in moulting hen willow ptarmigan Lagopus l. lagopus during snow melt[END_REF] and/or breeding [START_REF] Slagsvold | Predation favours cryptic coloration in breeding male pied flycatchers[END_REF], which provides additional though not conclusive evidence that pelage or plumage color reduces predation risk. Color resemblance is more beneficial in certain species than others [START_REF] Cott | Adaptive coloration in animals[END_REF]. For instance, nocturnal species such as owls need to be cryptic as they tend to remain still and sleep during daylight as suggested by [START_REF] Cott | Adaptive coloration in animals[END_REF]. However, even after long lasting research, there is still little systematic evidence revealing that plumage coloration has clear impact on predator avoidance. Scientists gradually turned their attention to the correlation between plumage coloration and mate preference (e.g. [START_REF] Bennett | Ultraviolet plumage colors predict mate preferences in starlings[END_REF][START_REF] Ballentine | Female mate choice in relation to structural plumage coloration in blue grosbeaks[END_REF][START_REF] Leitã O | Ultraviolet reflectance influences female preference for colourful males in the European serin[END_REF] and offspring sex allocation (e.g. [START_REF] Sheldon | Ultraviolet colour variation influences blue tit sex ratios[END_REF][START_REF] Griffith | Correlations between ultraviolet coloration, overwinter survival and offspring sex ratio in the blue tit[END_REF][START_REF] Romano | Sex allocation according to multiple sexually dimorphic traits of both parents in the barn swallow (Hirundo rustica)[END_REF].

ii Flocking danger than a solitary individual [START_REF] Darwin | The descent of man and selection in relation to sex[END_REF] because of collective detection (Pulliam, 1973). Individual response distance of detecting a predator also increases with flock size, which results in an increased probability of escape [START_REF] Kenward | Hawks and doves: Factors affecting success and selection in goshawk attacks on woodpigeons[END_REF]. If a predator only takes one prey individual or a number less than the size of a group, the probability of getting captured would be smaller than for a solitary individual of a prey [START_REF] Hamilton | Geometry for the selfish herd[END_REF]. This dilution of risk, the reduced probability of being captured in larger groups, has been observed numerous times (e.g. [START_REF] Munro | Gull predation and creching behaviour in the common eider[END_REF][START_REF] Cresswell | Flocking is an effective anti-predation strategy in redshanks, Tringa totanus[END_REF][START_REF] Beauchamp | Disentangling risk dilution and collective detection in the antipredator vigilance of semipalmated sandpipers in flocks[END_REF]. The detection and dilution benefits intertwine at some point [START_REF] Bednekoff | Re-examining safety in numbers: Interactions between risk dilution and collective detection depend upon predator targeting behaviour[END_REF]: vigilance provides relatively less and dilution more benefits in larger groups, but both benefits could reach limits, and the probability slightly decreases as group size continues to increase. Besides reducing predation risk, gathering in a group also reduces time spent vigilant, and it enhances foraging opportunities for individual prey [START_REF] Morse | Feeding behavior and predator avoidance in heterospecific groups[END_REF][START_REF] Ferná Ndez | Effect of group size on individual and collective vigilance in greater rheas[END_REF][START_REF] Beauchamp | Social predation: How group living benefits predators and prey[END_REF][START_REF] Beauchamp | Animal vigilance: Monitoring predators and competitors[END_REF].

iii Alarm calls When a prey individual has already discovered a predator, prey may emit alarm calls or perceive warning signals from other individuals. Alarm calls convey information about the threat, including the type of predator [START_REF] Seyfarth | Vervet monkey alarm calls: Semantic communication in a free-ranging primate[END_REF], the size of a predator (Templeton et al., 2005), the behavior of a predator [START_REF] Griesser | Referential calls signal predator behavior in a group-living bird species[END_REF], the urgency to respond [START_REF] Leavesley | Communicating about danger: Urgency alarm calling in a bird[END_REF] and many other clues for the threat. Thus, alarm calls protect individuals in the group that parasitize the anti-predator behavior of the individual that emits the alarm call, while benefiting the alarmed individual itself. There are false alarm calls performed as a means of resource usurpation, thereby increasing the callers' own probability of accessing food (e.g. [START_REF] Munn | Birds that "cry wolf[END_REF]Møller, 1988). Recognition of intra-and inter-species warning signals constitutes an important part of the anti-predator strategy of individuals that reduce the costs of responding to false alarms (Treisman, 1975;[START_REF] Koops | Reliability and the value of information[END_REF]Magrath et al., 2007).

iv Escape behavior If all of these previous actions fail, prey will have to face the predator directly. Prey can do nothing but escape when this encounter is inevitable. Unlike other anti-predator behavior (-kd) , 0 ≤ d ≤ dd, is the probability of survival.

The expected fitness (residual reproductive value) exceeds initial fitness where the benefits accrue more rapidly than risk increases. The optimal approach distance, predicted FID, occurs where fitness is maximized. Modified from [START_REF] Cooper | Optimal flight initiation distance[END_REF].

The shorter the distance between the prey and the predator, the higher the probability that the prey will be killed as escape takes time before starting while the predator gets closer. An individual who failed to escape when facing a predator ends up dead. An inefficient escape could cause injury to the prey although this may still imply survival [START_REF] Dickey | Chemically mediated effects of injured prey on behavior of both prey and predators[END_REF][START_REF] Heithaus | Shark-inflicted injury frequencies, escape ability, and habitat use of green and loggerhead turtles[END_REF] and even its subsequent breeding opportunities if they have damaged tails or wings [START_REF] Fitzpatrick | Magpies' tails: Damage as an indicator of quality[END_REF][START_REF] Jennions | Variation in mate choice and mating preferences: A review of causes and consequences[END_REF]). Escape appears to be a simple action: As long as the prey runs at the moment a predator is detected, the prey will achieve the maximum probability of survival from this encounter. An individual's response to a potential predator may be subject to trade-offs [START_REF] Ydenberg | The economics of fleeing from predators[END_REF][START_REF] Blumstein | Assessment and decision making in animals: A mechanistic model underlying behavioral flexibility can prevent ambiguity[END_REF][START_REF] Cooper | Optimal flight initiation distance[END_REF] because prey in addition to avoiding being pursued, also has to forage and reproduce. Direct flight implies termination/change of behavior in progress, which means giving up potential benefits. Even if individuals are resting when encountering a predator, leaving immediately causes them to consume extra energy (Tatner & Bryant, 1986), give up potential foraging habitat [START_REF] Brown | Vigilance, patch use and habitat selection: Foraging under predation risk[END_REF], and subsequently reduce individual fitness. Thus, animals have to optimize the distance at which they start escape, so the benefits of staying put are balanced against the costs of flight (Fig. 1; [START_REF] Ydenberg | The economics of fleeing from predators[END_REF]. This distance reflects the life history compromise between risk of predation and the benefits of foraging.

II Flight initiation distance

All animals flee from potential predators and humans, and wildlife react to humans in similar ways as they do to predators (Frid & Dill, 2002). Predation events characteristically follow a sequence: encounter, detection, identification, approach, subjugation and consumption from the perspective of predators [START_REF] Endler | Interactions between predators and prey. Behavioural ecology: An evolutionary approach[END_REF]. For this study of escape distance, humans are the presumed predators in the encounter. When an individual bird is initially seen, it is identified to species. The starting distance (SD) is the distance at which a human starts to approach the target individual, and alert distance (AD) is the distance at which the target individual shows clear alert behavior (Fig. 2). Flight initiation distance (FID) is the distance positively correlated with FID (e.g. [START_REF] Blumstein | Avian risk assessment: Effects of perching height and detectability[END_REF][START_REF] Cooper | When and how do predator starting distances affect flight initiation distances[END_REF][START_REF] Cooper | Strong artifactual effect of starting distance on flight initiation distance in the actively foraging lizard Aspidoscelis exsanguis[END_REF]. This relationship is first mathematical controlled (FID can only equal or be smaller than SD), but it has a biological component as well [START_REF] Dumont | Flight initiation distance and starting distance: Biological effect or mathematical artefact[END_REF]. Animals accrue an attentional cost for continued monitoring of an approaching predator (Blumstein, 2003;Samia & Blumstein, 2015). In this thesis, I target an individual with a binocular and approach the target from 100m away for large-sized species (heavier than 150g) or 30m away for smaller species (Fig. 3; Møller & Erritzøe, 2014) to eliminate this potential problem. I used the Pythagorean theorem to calculate the direct FID:

FID direct = √FID horizon 2 + Perching height 2 2
shown in Fig. 2. Flight is defined as when a focal individual is moving away either by foot or flight in response to approach. Finally, I record the height at which the individual was perching off the ground (if it was off the ground, otherwise this value was 0m). Distances were either measured in paces and converted to meters or by using a hand-held laser © Natavp Dreamstime.com rangefinder. Height was estimated by visually rotating the location of the individual comparing the position with the approaching person's height (Møller, 2008a).

There is an extensive literature on methodology of studies of FID, and they found a strong positive relationship between FID recorded by different observers, temporal consistency of FID in estimates from different years and consistent FID among different sites (e.g. Blumstein, 2003;[START_REF] Blumstein | Testing a key assumption of wildlife buffer zones: Is flight initiation distance a species-specific trait?[END_REF]Møller et al., 2008;Møller & Erritzøe, 2014). In those studies that have followed marked individuals, FID has been verified to have high repeatability (Carrete & Tella, 2010, 2013), which is a measure of intra-individual consistency. Thus, FID is a reliable metric of actual predation risk. The literature on FID, focusing on birds (Møller, 2015), mammals [START_REF] Stankowich | Mammals. Escaping from predators: An integrative view of escape decisions[END_REF] and lizards [START_REF] Cooper | Reptiles. Escaping from predators: An integrative view of escape decisions[END_REF], have identified a variety of factors that are correlated with FID [START_REF] Cooper | Escaping from predators: an integrative view of escape decisions[END_REF] as presented in Table 1. FID, as an indicator of anti-predator behavior, is also known to be heritable and subject to directional selection (Dall et al., 2004;Blumstein et al., 2010;Møller & Nielsen, 2010;Bize et al., 2012). et al., 1993;Blumstein, 2006;Møller & Garamszegi, 2012;Samia et al., 2015b) Wing shape (Ferná ndez-Juricic et al., 2006) Locations on and away from paths [START_REF] Eason | Factors affecting flight initiation distance in American robins[END_REF] Distance to refuge (Ferná ndez-Juricic et al., 2006;[START_REF] Rodriguez-Prieto | Antipredator behavior in blackbirds: Habituation complements risk allocation[END_REF][START_REF] Braimoh | Managing human disturbance: factors influencing flight-initiation distance of birds in a West African nature reserve[END_REF]) Urbanization Urban and rural habitat (Carrete & Tella, 2013;McGiffin et al., 2013;Møller et al., 2013a;Samia et al., 2017) Urban invasiveness (Carrete & Tella, 2011, 2015) Urban gradient [START_REF] Clucas | Attitudes and actions toward birds in urban areas: Human cultural differences influence bird behavior[END_REF]McGiffin et al., 2013) Disturbance Hunting (Laursen et al., 2005;Thiel et al., 2007;[START_REF] Braimoh | Managing human disturbance: factors influencing flight-initiation distance of birds in a West African nature reserve[END_REF]) Human disturbance [START_REF] Bregnballe | Escape distances from human pedestrians by staging waterbirds in a Danish wetland[END_REF][START_REF] Ge | The effects on birds of human encroachment on the Qinghai-Tibet Plateau[END_REF] Noise level [START_REF] Petrelli | First to flush: The effects of ambient noise on songbird flight initiation distances and implications for human experiences with nature[END_REF] Distance to human settlements [START_REF] Bjørvik | Bird flight initiation distances in relation to distance from human settlements in a Tanzanian floodplain habitat[END_REF])

III The heritability of escape behavior

Escape behavior is the last step in anti-predation behavior before capture. The individual is likely to face death once its escape fails. Therefore, effective escape behavior should have a strong hereditary component as its strong and direct link to survival affording limited opportunities for "practice". Most characters have a quantitative genetic basis with offspring resembling their parents in phenotype. Repeatability is an upper limit to heritability, and the product of heritability and the intensity of selection equals response to selection [START_REF] Falconer | Introduction to quantitative genetics[END_REF]. Thus, unbiased heritability estimates and selection estimates can be used to predict micro-evolutionary response. So, if for example the intensity of selection increases, we should be able to predict the increase in phenotype due to the response to selection. Generally, escape behavior is a response to the surrounding environment and is subject to natural selection. Fewer studies have investigated the heritability of behavior.

Behavior itself is a result of comprehensive performance in response to various factors [START_REF] Sih | Behavioral syndromes: An ecological and evolutionary overview[END_REF][START_REF] Bonduriansky | Nongenetic inheritance and its evolutionary implications[END_REF], including the physiological regulation [START_REF] Ricklefs | The physiology/life-history nexus[END_REF], cognitive ability [START_REF] Griffin | Training captive-bred or translocated animals to avoid predators[END_REF][START_REF] Cole | Cognitive ability influences reproductive life history variation in the wild[END_REF] and morphological constraints [START_REF] Foster | Determinants of lizard escape performance: Decision, motivation, ability, and opportunity. Escaping from predators: An integrative view of escape decisions[END_REF]. For many species, parents and their offspring live in geographically adjacent (if not the same) territories, and they are likely to behave similarly (Wilson, 1998). Maternal effects may also play an important role in affecting offspring behavioral responses to the environment including the maternal environment [START_REF] Eising | Avian mothers create different phenotypes by hormone deposition in their eggs[END_REF]. In addition, learning and imitation may be other explanations for similarities in behavior between generations, which may originate from parental care as well as among peers [START_REF] Koolhaas | Coping styles in animals: Current status in behavior and stress-physiology[END_REF][START_REF] Hamm | Do birds of a feather flock together? The variable bases for African American, Asian American, and European American adolescents' selection of similar friends[END_REF].

There are only few studies that provide evidence that escape behavior is heritable as it is difficult to study the heritability of escape behavior under field conditions. Juvenile scallops Argopecten purpuratus showed significant heritability and significant genetic correlation among several escape response traits using the full-sib/half-sib design [START_REF] Brokordt | Heritability and genetic correlations of escape behaviours in juvenile scallop Argopecten purpuratus[END_REF]. Garter snakes Thamnophis ordinoides showed significant heritabilities and genetic correlations among escape traits using pedigree-based quantitative genetic analysis [START_REF] Brodie | Genetic correlations between morphology and antipredator behaviour in natural populations of the garter snake Thamnophis ordinoides[END_REF], and its flight initiation distance showed a significant family effect [START_REF] King | Family, sex and testosterone effects on garter snake behaviour[END_REF].

Antipredator behavior of adult Alpine swifts Apus melba was significantly repeatable and heritable based on long-term behavioral observations of parents and cross-fostered offspring (Bize et al., 2012). Long-term data on FID in a population of barn swallows Hirundo rustica reported significant heritability of FID with a maternal clutch size effect and similar heritabilities based on father-offspring and mother-offspring resemblance (Møller, 2014).

The latter may suggest that maternal effects are not major determinants of FID in this species.

IV Predation risk and FID

i Predation risk and FID Predation risk is likely to have a concave upward relationship with distance to potential predators, and it increases sharply at short distances (Fig. 1; [START_REF] Cooper | Optimal flight initiation distance[END_REF].

This inherent assumption about risk-taking and FID has been confirmed by empirical evidence based on intra-and inter-species differences. A study on 30 Namibian rock agama Agama planiceps males found that bold males with relatively short FID suffered higher levels of tail loss, possibly due to predation [START_REF] Carter | Agamas exhibit behavioral syndromes: Bolder males bask and feed more but may suffer higher predation[END_REF]. Møller (2014) analysed long-term data on FID in a population of barn swallows Hirundo rustica during 1984-2013

with 2196 records for 1789 individuals. Among these birds, a total of 13 adults killed by cats Felis catus domesticus and 5 adults preyed on by sparrowhawks were identified from remains including rings. These 18 individuals that died from predation had siginificantly shorter FID than survivors. More indirect evidence from paired tropical bird species and closely related temperate bird species showed that tropical species had relatively shorter FID, as predicted by the large difference in abundance or diversity of the predator community related to latitude [START_REF] Møller | Tropical birds take small risks[END_REF].

The difference among species in mean FID also reflects the difference in risk of predation among species. For instance, in a comparative analysis of 40 bird species, species particularly susceptible to predation by sparrowhawks took flight at shorter distances (Fig. 4; Møller et al., 2008). The risk of predation by domestic cats (Møller et al., 2010) and the risk of getting hit by vehicles (Møller et al., 2011) were likewise negatively related to FID among species, and these relationships remained robust even after controlling for additional factors associated with risk of predation such as body mass and sexual dichromatism. Thus longer FIDs are associated with lower actual risk of predation and smaller levels of risktaking when experiencing a real predator.

Some studies have shown an effect of perceived risk of predation on FID of birds.

Artificially modified visibility did not affect flight decision of crimson rosellas Platycercus elegans when their overall perception of risk remained the same [START_REF] Boyer | Effect of visibility on time allocation and escape decisions in crimson rosellas[END_REF].

Double-banded plovers Charadrius bicinctus reacted to the presence of cats and other mammalian predators by increasing FID in response to approaching humans [START_REF] St | Presence of mammalian predators decreases tolerance to human disturbance in a breeding shorebird[END_REF]. A intraspecific study found that FID in nesting female song sparrows Melospiza melodia was siginificantly longer following experimental playback of predator calls than non-predator vocalizations (Zanette et al., 2011). ii Three potential variables predicting interspecific variation in FID a Body mass Take-off performance is reported to decline with increasing body mass (Metcalfe & Ure, 1995;Warrick & Dial, 1998). A relatively large flying organism takes longer before takeoff as with increasing body size the power requirements of flight increase faster than the ability of muscle to provide power (Tobalske & Dial, 2000). Besides the direct relation between body mass and flight performance, body mass is also the best predictor of lifehistory, behavior, physiology and risk of extinction [START_REF] Bennett | Evolutionary ecology of birds: Life histories, mating systems, and extinction[END_REF]. There are reasons to believe that FID and body mass are significantly associated. Scientists noticed ©2010 Steve Oakes, AEBS Limited that smaller birds were more approachable than larger species long age [START_REF] Hemmingsen | The relation of shyness (flushing distance) to body size[END_REF][START_REF] Cooke | Observations on how close certain passerine species will tolerate an approaching human in rural and suburban areas[END_REF]. One of the best predictors of response of birds to human disturbance is body mass (Samia et al., 2015b). Many studies reported consistent positive correlations between FID and body mass. Blumstein (2006) reported an effect size in terms of Pearson's productmoment correlation coefficient of 0.044 for 150 bird species. Ferná ndez-Juricic et al. (2006) specifically analyzed body mass and FID of 83 species from 29 families and found an effect size of 0.585, while [START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF] reported FIDs and body mass information for 250

Australian birds and found an effect size of 0.48. Møller (2008a) studied urban populations of 40 bird species and reported an effect size of 0.78. A meta-analysis dealing with FID in birds reported the second largest (following urbanization) mean effect size (0.39) of body mass among different categories of phenotypic traits (Møller, 2015). Thus large species have relatively long FID (Fig. 5). et al., 2012). Møller (2008c) found that this relationship was much weaker in a phylogenetic regression based on observations of 100 European bird species with a slope (SE) = 0.20 (0.10), much smaller than one. Thus, FID increases slower than body mass and large species have relatively shorter FID for their body mass.

b Morphology

Morphological and behavioral characteristics influence interspecific variation in escape behavior. [START_REF] Bauwens | Evolution of sprint speed in lacertid lizards: Morphological, physiological, and behavioral covariation[END_REF] found that the evolution of escape behavior (high maximum sprinting abilities) was mechanistically related to the evolution of morphology (longer hindlimbs relative to body length) across 13 species of lizards. Morphology of birds was closed related to flight performance and energy cost as predicted by flight dynamic theory [START_REF] Rayner | Form and function in avian flight[END_REF]. Migratory birds showed a decreased escape speed with increasing wing loading (mass/wing area) [START_REF] Burns | The effects of wing loading and gender on the escape flights of least sandpipers (Calidris minutilla) and western sandpipers (Calidris mauri)[END_REF]. The morphology of wingtip shape and hind limb morphology also influence interspecific variation in predation rates in passerines [START_REF] Swaddle | Morphological adaptations to predation risk in passerines[END_REF]. Thus, FID in birds could vary with wing and hind limb morphology. For instance, a comparative study on 83 bird species showed that birds with more pointed wings fled at longer distances and landed farther away than species with rounded wings (Ferná ndez-Juricic et al., 2006). Similarly, species with long FID for their body size also had large wing areas and aspect ratios (Fig. 6; Møller et al., 2013b). The relationship between morphology of species and FID could also be explained from a physiological perspective as FID is negatively related to haematocrit, a measure of packed red blood cell volume and as such indicates the oxygen transport ability and hence the flight muscle contraction reaction of individuals (Møller et al., 2013b). Basal metabolic rate (BMR), representing the minimum level of metabolism that allows normal functioning by an individual in its environment, was also positively related to FID (Møller, 2009). Thus, escape behavior has cooperated with a number of different adaptations and constrains in prey in terms of morphology. interact with natural habitats [START_REF] Dukas | Cognitive ecology II[END_REF]. A number of studies has shown that animals use cognitive abilities for accessing the behavior of predators manifested as changed flight distance. For instance, birds have shorter FID if they are approached tangentially rather than directly [START_REF] Ferná Ndez-Juricic | Sensitivity of wildlife to spatial patterns of recreationist behavior: A critical assessment of minimum approaching distances and buffer areas for grassland birds[END_REF][START_REF] Geist | Does intruder group size and orientation affect flight initiation distance in birds?[END_REF]Møller & Tryjanowski, 2014), or if they are approached with human eyes looking elsewhere rather than looking directly at them [START_REF] Bateman | Who are you looking at? Hadeda ibises use direction of gaze, head orientation and approach speed in their risk assessment of a potential predator[END_REF]. In a comparative study of 107 species, Møller & Erritzøe (2014) found that birds with relatively large brains for their body size avoided the rush when a predator approached. The negative correlation could be caused by species with relatively large brains experiencing more opportunity costs monitoring the intention of the predator (e.g. through a better assessment of a predator's distance and speed) (Cooper & Blumstein, 2014). They make the least expensive escape decision after assessment and monitoring of the threat of predation thereby reducing the energy costs of flight (Samia et al., 2015b). Relative brain size also indirectly influenced invasion of urban habitats through its positive effect on inter-individual variability in FID (Carrete & Tella, 2011). Europe, the size of breeding populations in the Western Palearctic was smaller in species with long mean FIDs and small variances in FID (Møller & Garamszegi, 2012). In a comparative study of 56 species across Europe, species with long FID also showed a higher frequency of declining populations than species with short FID (Møller, 2008c). These findings suggest that mean FID for different species provides reliable information about the population consequences of risk-taking behavior by individuals and the susceptibility of different species to disturbance.

Nevertheless the association between FID and population trend is more complex than it seems. In an intercontinental study considering 193 species of birds from three continents, North America, Australia and Europe, continent and FID showed a significant interaction among all variables explaining population changes of birds. While bird populations were declining with increasing FID in Australia and Europe, the opposite pattern was found in North America (Møller et al., 2014). Another study on 46 bird species in England also failed to find a significant relationship between species population change and FID (Thaxter et al., 2010). These cases triggered studies on the geographic pattern of eacape behavior, and a follow up study showed interactive effects of species escape behavior and geographical location on Eurpean bird population trends [START_REF] Dí Az | Interactive effects of fearfulness and geographical location on bird population trends[END_REF]. The susceptibility to predation by sparrowhawks (Møller, 2014) and adult survival rate (Møller & Garamszegi, 2012) was significantly positively related to mean FID. Still, population size and population trend tend to be the net result of complex interations between habitat alteration at the breeding grounds, climate change and migratory strategies [START_REF] Cuervo | Temporal variation in population size of European bird species: Effects of latitude and marginality of distribution[END_REF][START_REF] Reif | Long-term trends in bird populations: A review of patterns and potential drivers in North America and Europe[END_REF] combined with escape behavior [START_REF] Dí Az | Interactive effects of fearfulness and geographical location on bird population trends[END_REF].

ii Urbanizaion

Scientists have noticed that urban species generally have relatively short FID compared to their rural counterparts (Fig. 7; [START_REF] Cooke | Observations on how close certain passerine species will tolerate an approaching human in rural and suburban areas[END_REF][START_REF] Sol | Behavioural adjustments for a life in the city[END_REF]Møller, 2015;Samia et al., 2017). The magnitude of the difference is directly related to time since urbanization (Møller, 2008a). The variation in relative FID (controlled by body mass) of urban populations is positively related to urban population density of different species [START_REF] Lin | Does avian flight initiation distance indicate tolerance towards urban disturbance?[END_REF]. The magnitude of variance could also be predicted by the number of generations since urbanization (Møller, 2008a), as expected by a gradual selection for urban life. Six different components of escape behavior were related to urbanization, suggesting that antipredator behavior has diverged between ancestral rural populations and recently established urban populations [START_REF] Møller | Escape behaviour of birds provides evidence of predation being involved in urbanization[END_REF]. Thus, the difference in FID between rural and urban habitats is likely related to recent changes in the predator community following urbanization. Indeed, this difference in FID paralleled trends in raptor abundance, as it decreased with increasing latitude (Dí az et al., 2013). Besides differences in the community of predators, other potential impacts of urbanization that increase individuals' body condition [START_REF] Geue | Reduced parasite infestation in urban Eurasian blackbirds (Turdus merula): A factor favoring urbanization[END_REF][START_REF] Delgado-V | Parasite-bird interactions in urban areas: Current evidence and emerging questions[END_REF], the availability and reliability of food [START_REF] Jokimä Ki | Biogeographical comparison of winter bird assemblages in urban environments in Finland[END_REF][START_REF] Galbraith | Supplementary feeding restructures urban bird communities[END_REF] also reduce the relative cost of flight. For instance, the presence of feeders in urban habitats also independently accounted for a reduction in FID as shown by a study of winter populations in Poland and differences in predators between urban and rural environments [START_REF] Møller | Urban habitats and feeders both contribute to flight initiation distance reduction in birds[END_REF].

However, not all species are equally adapted to urbanization (McKinney, 2002(McKinney, , 2006;;Morelli et al., 2016). For instance, the ubiquitous presence of humans and constant disturbance by vehicles could preclude most species from successfully invading cities. A study in Europe found that species successfully colonizing urban areas had larger variances in FID in their rural populations than unsuccessful colonizers [START_REF] Møller | Interspecific variation in fear responses predicts urbanization in birds[END_REF]. This supports the hypothesis that urbanization resulted from differential colonization of urban areas by species with heterogeneous levels of fear in the ancestral rural populations. A study on 42 bird species in a recently established South American city also found that inter-individual variability in fear of humans was positively related to contemporary urban invasion in birds, positively enhanced by species relative brain size (Carrete & Tella, 2011). Thus, FID may play a crucial role in urbanization of birds and species with relatively large variance in escape behavior rather than tame animals are expected to adapt better to the urban environment. In addition, urban environments are likely to create a safe refuge for prey because predators show greater levels of fear toward the proximity of humans than do their prey (Møller, 2012). Species-specific mean and variance of FID leads to distinct population trends for different species and contributes to biotic homogenization in urban environment. Modified from Samia et al. (2017).

iii Non-lethal effects

As FID is determinded by the conflicting benefits of energy gain and the risk of mortality from predation or other causes, relatively longer FID implies earlier abandonment of local resources and more energy consumption under the same level of disturbance than short FID.

The immediate cost of lowered resource availability can then be translated into a reduction in reproductive output or in long-term survival (Lima, 1998). Besides the energy cost of flight, the attentional cost of monitoring predators to assess predation risk also requires energy consumption, which explains why FID increases as alert distance (AD), or its t = 12.46*** r = 0.79 surrogate, starting distance (SD) increases (Cooper & Blumstein, 2014). The nonlethal effects of FID, together with direct predator consumption and other nonlethal effects that reduce or limit energy intake, can all reduce population density of prey [START_REF] Abrams | Foraging time optimization and interactions in food webs[END_REF].

As a quantitative measure of tolerance of birds to disturbance, variance of FID is expected to predict the diversity of behavioral responses to the environment. Species with a greater diversity of escape behavior exploit more different habitats by successfully coping with different unpredictable environmental conditions. Given the strong individual consistency in FID, the distribution of individuals among habitats is largely depending on their susceptibility to human disturbance as shown by burrowing owls Athene cunicularia (Carrete & Tella, 2010). Evidence from 133 bird species in Europe supports that species with a greater variance in FID exploits a greater diversity of habitats than those with relatively smaller variance (Møller & Garamszegi, 2012). Both within and between poulation variance in FID were significant indicators of habitat diversity of species (Garamszegi & Møller, 2017). Microhabitat choice and song post exposure of male collared flycatche Ficedula albicollis during sexual signalling is closely related to FID, as mediated by intrinsic individual temperament [START_REF] Garamszegi | Birds reveal their personality when singing[END_REF]. The effect of variance in FID on habitat selection can also be reflected in differences of invasions of urban habitat, as mentioned in the previous section.

VI Conservation and management implications

Manuscript No. 2 p. 65-71 (Anti-predator escape distances of common and threatened birds)

Humans extensively influence other creatures living on the planet and perhaps, therefore, we experience a loss of biological diversity [START_REF] Mcneely | The sinking ark: pollution and the worldwide loss of biodiversity[END_REF][START_REF] André N | Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: A review[END_REF]Vitousek et al., 1997;[START_REF] Parmesan | A globally coherent fingerprint of climate change impacts across natural systems[END_REF]. Surprisingly, the disturbance from human activity was found to be the most important factor for richness, supplanting even habitat loss and fragmentation in many cases in a model selection study on land bird communities in an urbanizing environment [START_REF] Schlesinger | Distinguishing stressors acting on land bird communities in an urbanizing environment[END_REF]. This is plausible because human-caused stimuli could be regarded as a form of predation risk considering its similarity to predation risk. It indirectly affects fitness components and population dynamics via energetics and lost opportunity costs of risk avoidance (Frid & Dill, 2002). Although disturbed populations are more tolerant to human disturbance than less disturbed populations (Samia et al., 2015b), a problematic situation emerges when humans are regarded as potential predators, and a growing tolerance in prey might increase their vulnerability to predators [START_REF] Geffroy | How nature-based tourism might increase prey vulnerability to predators[END_REF]. With the continuous expansion of human impact, the protection of wild species is getting increasingly important. Escape behavior provides important means for resolving conservation problems in the pursuit of more efficient means of conservation.

Nowadays, the most common application of FID on conservation is to define "buffer distance" or "buffer zones" (e.g. [START_REF] Rodgers | Set-back distances to protect nesting bird colonies from human disturbance in Florida[END_REF][START_REF] Rodgers | Buffer-zone distances to protect foraging and loafing waterbirds from disturbance by personal watercraft and outboard-powered boats[END_REF].

Similarly, FID is also used as a reference for landscape design in nature reserves or parks (Ferná ndez-Juricic et al., 2001a, b;[START_REF] Blackwell | Wildlife collisions with aircraft: A missing component of land-use planning for airports[END_REF] to reduce human impacts on wildlife. Some of these studies focused on threatened species (e.g. [START_REF] Gonzá Lez | Effect of human activities on the behaviour of breeding Spanish imperial eagles (Aquila adalberti): Management implications for the conservation of a threatened species[END_REF]Zuberogoitia et al., 2014), while others tried to include as many species as possible to establish a uniform standard for local species conservation as [START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF] suggested for managing disturbance to Australian birds.

Research questions I Does escape behavior interfere with genetic variance?

While scientists have found significant though complex relationship between population size, population trend and FID, there is little knowledge about the relationship between effective population size and FID. Inbred populations are threatened because they have little scope for micro-evolutionary responses to environmental change, and the fecundity and the viability of inbred individuals is often reduced compared to outbred individuals. Escape behavior provides the underlying behavioral mechanism accounting for the response of individuals to adverse environmental conditions. I predict that species with relatively long FID are also those with large genetic variability. Short FID indicating higher predation risk either promotes a smaller population size with genetic variability or could be a result of low genetic variability in such species. By establishing a correlation between antipredator escape distances and genetic variability, we may be better able to understand the mechanisms accounting for reductions in population size, but also adopt better choice of individuals for recovery projects considering the large numbers of predators in the wild.

II Could FID perform as an indicator of threat status of species?

Threat status of species is assessed based on the extent of their habitat, population size, population development in recent years, and many other factors. Meanwhile, flight initiation distance reflects the life history compromise between risk of predation and the benefits of foraging both at short and long term time frames. Species with relatively short FID are better able to cope with the proximity of humans and may have relatively more time and opportunities to get food and a superior reproductive and survival prospect in the environment with high human interference. Thus, FID may be a practical predictor of threat status of different species. I expect that relatively threatened species should have longer FID compared to closely related species, given the increasing rate of human disturbance and the standards for threat status. I verified the relationship between mean FID of species and threat status in closely related species.

III Could FID contribute to long-term trait evolutionary distinctiveness?

Predator-prey coevolution may result in rapid divergence in both predators and prey, and escape behavior as the last line of predator evasion should play a crucial role in the survival of individuals. Evolutionary distinctiveness (ED) reflects the phylogenetic isolation of taxa with high values characterizing species with unique phenotypes that deviate the most from other taxa. While most conservation concern is put on the world's most evolutionarily distinct species, the over-all phylogenetic distinctiveness in urban areas is decreasing across the world. Appropriate escape decisions should balance the costs from lost foraging or mating opportunities, and the benefits of escape from reduced predation risk. Such antipredator behavior should affect the ability to avoid predation and should therefore contribute to high ED values of certain species. I expect that ED is positively related to FID because species that take the smallest risks when encountering predators are less susceptible to predation. Testing for this correlation between ED and behavioral traits under strong selection may help us understand the evolution of ED and hence allowing for better protection of such species.

IV Is there any "side-effect" of early escape?

Although individuals that take early flight from approaching predators take small risks in encounters, they also have to take off more frequently at the same frequency of interference.

Short and brief aerial flapping flight is metabolically expensive that may result in 23 times basal metabolic rate (Tatner & Bryant, 1986). Frequent escape flights when encountering potential predators are energetically expensive and stressful, potentially contributing to the production of free radicals and hence oxidative stress, an outcome of metabolism. Oxidative stress plays a core role in the evolution of optimal investment patterns between reproduction and survival and other fitness components. Physical activity is an important potential cause of oxidative stress but surprisingly, no study has examined how oxidative stress is related to escape behavior which reflects the life history compromise between risk of predation and the benefits of foraging. I predict that species with relatively short FID for their body mass would experience more oxidative stress as frequent flight take-offs result in high energy consumption and stress. I tested this possible causal relationship in comparative analyses with three different indicators for oxidative stress and considered body mass and brain size as confounding factors.

V Does social behavior affect escape behavior?

Sociality (directly related to group size) is found to have an intermediat mean effect size of 0.26 on FID in a meta-analysis of cooperating factors in birds (Møller, 2015). Group size has also been suggested to be an important prey trait that influences escape decisions (Samia et al., 2017). Both collective detection (i.e. increased likelihood of detecting a predator in larger groups; Pulliam, 1973) and the dilution of risk (i.e. reduced probability of being captured in larger groups; [START_REF] Hamilton | Geometry for the selfish herd[END_REF] could potentially affect individual's escape behavior as group size changes. Previous studies had demonstrated that FID was positively related with flock size (Laursen et al., 2005;Tä tte et al., 2018). However, gregariousness (the tendency to live in flocks) could potentially affect individual's capacity to communicate with others and subsequently affect individual's escape behavior. As a consequence, the aim of this study was to test if FID in birds increased with flock size, focusing on differences between gregarious and non-gregarious species.

Summary I Escape from predators and genetic variance in birds

This study used phylogenetic generalized least square analyses weighted with sample size in 128 species of birds. The results revealed that three proxies for genetic variability, (1) minisatellite band sharing (Fig. 8), (2) heterozygosity and (3) inbreeding coefficient, were all related to the robust proxy of real predation risk (FID). Thus, higher levels of genetic potentially confounding effects of variables such as breeding range, population size and body mass.

II Anti-predator escape distances of common and threatened birds

This study associated extinction risk to escape distance in European birds. By analyzing the FID of 48 pairs of closely related bird species differing in their threat status, I concluded that threatened birds generally have a higher FID than non-threatened close related species.

This difference in FID between common and threatened species was almost two-fold and was consistent in both parametric and non-parametric tests.

III Evolutionary distinctiveness covaries with anti-predator behavior in bird communities

This chapter focused on the possible role of escape behavior (FID) in an evolutionary context in waterbirds. A total of 48 migratory and 30 resident water birds were investigated.

The phylogenetic generalized linear model results showed a significant positively correlation between ED score and the relative FID (controlled by body mass) (Fig. 9). This result was robust to differences in sampling effort and the potentially confounding effects of body mass, migratory status, the extent breeding ranges and similarity among taxa due to common phylogenetic descent.

IV Flight initiation distance is correlated with oxidative stress in birds

This study tested the relationship between FID and three oxidative stress markers (malondialdehyde, MDA, total antioxidant status, TAS and uric acid, UA) over 72 bird species. To model the relationship, I used phylogenetic generalized least square (PGLS) regression models, followed by phylogenetic path analysis to examine the potential causal relationships between several traits. The main finding of this study was that mean FID of different species of birds was positively correlated with species-specific MDA and UA levels and mediated through their relationship with body mass. This result was robust to differences in sample size and similarity due to common phylogenetic descent.

V Contagious fear: Flight initiation distance increases with flock size in gregarious birds

A total of 7,768 observations of 35 bird species from eight different European countries was collected. Different species were classified based on three ecological variables: trophic guild, body mass and gregariousness. Two series of models were run: First controlling for the phylogenetic signal among species and then non-phylogenetic models using flock size as a fixed factor and other variables as random factors. The main finding of this study was that social birds reacted to a potential predator quickly (as represented by relatively long FID) when aggregated in large flocks (Fig. 10), while that was not the case in non-gregarious species. These effects were independent of body mass and geographic area where data were collected, as well as phylogenetic signal among species.

Perspectives

At least three mechanisms have been proposed to account for differences in FID between populations of animals living in urban and rural habitats [START_REF] Møller | Urban habitats and feeders both contribute to flight initiation distance reduction in birds[END_REF]Samia et al., 2015b;Miranda, 2017). First, the increased tolerance could result from habituation.

Habituation-like processes occur when individuals are particularly sensitive to unexpected behavior from humans and potential predators but not expected behavior. Changes in population mean FID could be due to the fact that human activities are harmless and regular most of the time. Second, differential selection among behavioral syndromes could explain variation in recruitment to urban habitats leading to phenotypic sorting under different interference pressures between urban and rural habitat. Third, local adaptation to urban habitats implies that specific genotypes have increased in frequency or become favored 2012; Carrete & Tella, 2013;Miranda et al., 2013). In order to understand the underlying mechanism of these differences, we need well-designed experiments. Colors indicate bird family, and circle size is proportional to body mass of birds (g).

Envelopes around lines are 95% confidence intervals.

mating and reproduction strategies (Møller, 2014), genetic systems [START_REF] Storfer | Gene flow and ineffective antipredator behavior in a streambreeding salamander[END_REF] and morphology [START_REF] Losos | The effect of body armature on escape behaviour in cordylid lizards[END_REF]. These correlations suggest that escape behavior has potential use as a relatively easily accessed indicator of an organism's overall status in its environment. Relative mean FID and variance in FID of species should be regarded more as a predictor of identifying species that are potentially more vulnerable to increasing human disturbance rather than just measurements of "buffering distance". By involving antipredator escape distances in conservation plans and recovery projects, it may be possible to assess why some species become threatened while others do not. It might also be possible to identify species that are prone to population declines beforehand by relying on FID as a predictive tool. Such behavioral differences may provide means of recovery of such threatened species from threats caused by the presence of predators including humans.

Nevertheless, well-designed experiments may allow analysis of the direction of causation and give a better understanding of FID, behavioral syndromes and their ecological significance.

Magrath

Evolutionary distinctiveness covaries with anti-predator behavior in bird communities

Evolutionary distinctiveness (ED) reflects the phylogenetic isolation of taxa with high values characterizing species with unique phenotypes that deviate the most from other taxa.

Testing for the correlation between ED and behavioral traits under strong selection may help us understand the evolution of ED values. Anti-predator behavior reflecting the interaction between prey and predator is such a factor. We examined the relationship between ED and flight initiation distance (FID, the distance at which an animal takes flight when approached by a human), which signifies an important component of the anti-predator strategy of individuals belonging to any species. Overall, ED was positively related to FID, implying that species that were particularly evolutionarily distinct were also the species that took the smallest risks when encountering predators, and such species were less susceptible to predation. One potentially confounding factors was body mass, which was negatively related to ED and positively related to FID. The migratory status of species was only weakly correlated with ED in a linear model, although we did not find significant relationships between ED and the extent of breeding range or migratory behaviour. This is the first attempt to relate current anti-predator behavior to evolutionary distinctiveness. The results contribute to establishing a link between ED and life-history traits, helping us to understand the evolution of ED and hence allowing for better protection of such species.

Keywords: migratory status, phylogenetic linear regression, waterbird

Planet earth is in the midst of an ongoing extinction spiral with extensive loss of species and their associated functions. Some species have specific evolutionary, ecological and morphological traits [START_REF] Pavoine | Is the originality of a species measurable ?[END_REF][START_REF] Redding | Evolutionary distinctiveness, threat status, and ecological oddity in primates[END_REF]) that result in their extinction causing greater loss than species with common phenotypes. A quantitative measure of genetic or evolutionary uniqueness is evolutionary distinctiveness (ED), based on branch lengths of species and the number of closely related taxa [START_REF] Isaac | Mammals on the EDGE: conservation priorities based on threat and phylogeny[END_REF]. ED is expected to capture unique genomes and functions of species and hence reflect an important component of biodiversity (Warren et al. 2008[START_REF] Redding | Evolutionary distinctiveness, threat status, and ecological oddity in primates[END_REF]. ED values of indigenous species constitute phylogenetic diversity of a local community [START_REF] Vane-Wright | What to protect? -Systematics and the agony of choice[END_REF]. This attribute predicts the function of local ecological assemblages in plant communities [START_REF] Cadotte | Phylogenetic diversity promotes ecosystem stability[END_REF] and is regarded as an additional component of biodiversity with important significance for conservation [START_REF] Veron | Predicting loss of evolutionary history: Where are we?[END_REF].

Among 9993 bird species on earth, ED is distributed very unevenly [START_REF] Redding | Incorporating evolutionary measures into conservation prioritization[END_REF]. Of all bird species, the top 10% most evolutionarily distinct species represents approximately one-third of total phylogenetic diversity (Jetz et al. 2014; Fig. 1). The most evolutionary distinct birds include both threatened and isolated species such as giant ibis

Thaumatibis gigantea and widely distributed common species such as osprey Pandion haliaetus, which can be found in almost every environment on earth. The origin of species with high ED through natural selection and other evolutionary processes remains ambiguous.

Still we are losing avian phylogenetic diversity in anthropogenically modified habitats (Morelli et al. 2016).

Species with high ED could be the result of speciation or extinction among relatives. Many studies have investigated the phylogenetic and geographic distribution of species and concentrated on species with top level ED (e.g. Cadotte and Jonathan Davies 2010, Jetz et al. 2014). For example, while mountains are thought to harbor stable local conditions and thus high persistence of species [START_REF] Fjeldså | The role of mountain ranges in the diversification of birds[END_REF], they show no correlation with high ED (Jetz et al. 2014) as in the case of isolated islands (Jetz et al. 2012). Still, isolated landmasses exhibit a cluster for the world's top 1,000 (i.e., top 10%) ED species (Jetz et al. 2014). Thus, species from different continents may have very different reasons for resistance to evolutionary distinctiveness. Resident species are known or thought to inhabit a given locality throughout the year while migratory birds have seasonal movements from their breeding area to the wintering area. Migrants suffer more potential selective pressures in type of variance habitats, predators, parasites and other species than residents, while residents experience relatively greater geographical isolation during differentiation of populations [START_REF] Cox | The Evolution of Avian Migration Systems between Temperate and Tropical Regions of the New World[END_REF]. The breeding range may also contribute to greater ED as species diversity among bird families was positively correlated with geographical range occupied by each family [START_REF] Owens | Species richness among birds: body size, life history, sexual selection or ecology?[END_REF]. A large geographical range increases diversification rates as a buffer from relatively localized environmental disturbances [START_REF] Cardillo | Geographic range size, life history and rates of diversification in Australian mammals[END_REF].

Most conservation concern is put on the world's most evolutionarily distinct species (e.g. Jetz et al. 2014[START_REF] Veron | Predicting loss of evolutionary history: Where are we?[END_REF], raising particular concerns for isolated landmasses including Australia and New Zealand. Simultaneously, the over-all phylogenetic distinctiveness in urban areas is decreasing across the world (Morelli et al. 2016, Sol et al. 2017). Uncovering relevant components of species with high ED scores would help us understand the causes, and this knowledge may have a key effect on protection of species at a global scale.

One possible commonality for high-ED species is anti-predator behavior. Predation imposes strong natural selection on most animal species, and anti-predator behavior affects the ability to avoid predation for prey (Caro 2005). High ED species may once have had close relatives that went extinct in the process and became the only species left in a given clade. Originality or possible irreplaceability of species in ecological niches and a unique role in ecosystems may result in only individuals with effective anti-predator behavior surviving or surviving disproportionately. Appropriate escape decisions should balance the costs from lost foraging or mating opportunities, and the benefits of escape from reduced predation risk [START_REF] Cooper | Escaping from predators: an integrative view of escape decisions[END_REF]. Such anti-predator behavior should affect the ability to avoid predation and effective anti-predator behavior should therefore contribute to high ED values of certain species.

Numerous anti-predator behavior metrics exist such as color resemblance, alarm calls, warning signals and escape behavior (Caro 2005), and the origin and the maintenance of this diversity begs an explanation. Unlike other anti-predator behavior with potential followup strategies in the case of failure, escape behavior is the last line of defense [START_REF] Cooper | Escaping from predators: an integrative view of escape decisions[END_REF]. It is of particular importance for survival. Flight initiation distance (FID), measured as the distance at which an animal flees when approached by a human (Blumstein 2003, Møller et al. 2008), is a reliable metric for monitoring escape behavior [START_REF] Blumstein | Habituation and sensitization: new thoughts about old ideas[END_REF]. In studies of individually marked individuals, FID is highly repeatable (Carrete andTella 2010, 2013) and heritable (Dall et al. 2004, Blumstein et al. 2010, Møller and Nielsen 2010, Bize et al. 2012) and should also be subject to strong selection [START_REF] Abrams | The evolution of predator-prey interactions: theory and evidence[END_REF].

Waterbirds have similar life-cycles and are ecologically homogeneous with respect to the use of habitats and avoidance of potential predators compared with other taxa [START_REF] Lack | Evolution illustrated by waterfowl[END_REF].

They are more likely to share similar adaptive evolution in relatively similar aquatic environments as reflected by adaptive convergence [START_REF] Reznick | The population ecology of contemporary adaptations: what empirical studies reveal about the conditions that promote adaptive evolution[END_REF] and speciation [START_REF] Schluter | Ecology and the origin of species[END_REF]) are partially environmentally dependent. Aquatic environments show little variability in terms of habitat differences and the degree to which they early detect predators (Caro 2005). That is the case despite scientists only documenting small effect of open habitats (Blumstein 2006) and habitat complexity (Møller and Erritzøe 2010) on flightiness. Thus, waterbirds constitute a relatively uniform community of species.

The objective of this study was to investigate the association between evolutionary distinctiveness and anti-predator behavior. Because species with long FID have high survival rates (Møller and Garamszegi 2012), and because they are particularly able to escape predation (Møller et al. 2008), we would expect a positive relationship between ED and FID. We also included three potential confounding factors affecting this association:

body mass because large-sized species are better able to escape predation (Møller and Garamszegi 2012), migratory status because migrants interact with relatively more variable local species and experience different environmental conditions, while different resident populations are more isolated [START_REF] Cox | The Evolution of Avian Migration Systems between Temperate and Tropical Regions of the New World[END_REF] and the size of the breeding range because high species diversity in a certain family is strongly positively associated with large geographical ranges [START_REF] Owens | Species richness among birds: body size, life history, sexual selection or ecology?[END_REF], which represent morphological traits, life-style and geographical range, respectively. Accounting for these correlations is not only essential for explaining the relationship between life-history and evolution, but also critical for assigning a prospective conservation value in different species.

Material and Methods

Evolutionary distinctiveness

ED score for each species was calculated at each node between the tips and root for the species in different orders [START_REF] Isaac | Mammals on the EDGE: conservation priorities based on threat and phylogeny[END_REF], based on species' branch length and number of closely related taxa [START_REF] Faith | Conservation evaluation and phylogenetic diversity[END_REF]). We used published ED scores (Jetz et al. 2014) for birds as this index is robust to taxonomic changes [START_REF] Isaac | Mammals on the EDGE: conservation priorities based on threat and phylogeny[END_REF]) including the effect of phylogenetic uncertainties [START_REF] Sol | Risk-taking behavior, urbanization and the pace of life in birds[END_REF].

Recording flight initiation distance FID data were collected in an area of 800 km 2 in Northern Jutland (57°12'N, 10°00'E), Denmark from 2006-2016 combined with additional data collected in Spain, France, Iceland, (2008). FID was recorded by approaching foraging or resting birds by walking at a normal speed and recording the distance at which the individual took flight or walked away. Few individuals were resting above the ground level. In these cases, the perching height was recorded and FID was estimated as the Euclidian distance and the other two sides were horizontal distance and the perching height, respectively. All estimates were collected in rural habitats to avoid any potential inference between habitat dimension and FID (Møller 2012, Samia et al. 2017). Only water birds with similar habitat openness were considered because distance to refuge affects FID [START_REF] Dill | The influence of distance to refuge on flight initiation distance in the gray squirrel (Sciurus carolinensis). -Can[END_REF], and species may develop different strategies under various circumstances [START_REF] Kappeler | Constraints and flexibility in mammalian social behaviour: introduction and synthesis[END_REF].

Additional data

Information on body mass (g) of species was extracted from Dunning (2007). A mean value was used if the body masses of males and females were provided separately. Information on the breeding area of migratory and resident species estimated as the global range of the breeding area (in km 2 ) was collected from Birdlife International (2017). We also scored species as resident or migratory. When species had variable migratory status across its geographical range, we recorded migratory behavior dependent on the population actually studied. All information is provided in the Appendix A.

Comparative analyses

All analyses were made with R 3.4.0 (R Core Team 2017). We log10-transformed body mass and breeding area to obtain variables that were normally distributed and log10-transformed evolutionary distinctiveness to obtain normal distribution of the residuals, allowing the use of parametric statistics. Models were weighted by sample size (the number of individuals)

to account for the fact that sample sizes differed among taxa, giving each datum a weight that reflects its degree of precision due to sampling effort [START_REF] Sokal | Biometry: The principles and practices of statistics in biological research[END_REF] and avoiding any bias in sampling [START_REF] Garamszegi | A meta-analysis of correlated behaviours with implications for behavioural syndromes: mean effect size, publication bias, phylogenetic effects and the role of mediator variables[END_REF]. We avoided over-representation of taxa with large sample sizes by using the square-root transformed number of individuals as a weighting factor. FID increases consistently with body mass (Blumstein 2006, Ferná ndez-Juricic et al. 2006, Møller 2008b, 2015; effect sizes range from 0.04 to 0.96 with a mean of 0.45). We calculated the residuals of a log-log linear regression of FID against body mass (linear regression weighted by sample size, r 2 = 0.18, F1, 76 = 16.5, P = 0.0001). We used residuals as a measure of relative FID. Because the comparative analysis concerned interspecific variation of trait values and the potential correlations could be subject to evolutionary forces and due to common ancestor (Garamszegi 2014), we used both generalized linear model and phylogenetic generalized linear model using the libraries ape (Paradis et al. 2004) and nlme (Pinheiro et al. 2017). We extracted the phylogenetic relationship for 78 species from the phylogeny available on line (Jetz et al. 2012(Jetz et al. , 2014) ) and obtained consensus phylogenies from the downloaded 100 trees with Mesquite 3.31 (Maddison and Maddison 2017).

Results

A total of 48 migratory and 30 resident water birds were investigated. Evolutionary distinctiveness scores ranged from 1.18 (Anas platyrhynchos) to 49.48 (Gavia stellata) (Fig.

2

) showing a pattern similar to that of birds in general. A generalized linear model showed that ED score was positively related to relative FID (Table 1, Fig. 3). Similarly, a phylogenetic generalized linear model showed that ED was negatively related to body mass (Table 1, Fig. 4). Migratory status was weakly negatively related to ED in the linear model, although the significance of this relationship disappeared in the phylogenetic model (Table 1, Fig. 5). We found no significant correlation between ED and breeding range in either model (Table 1). These results imply that species with large ED are also those that take smaller risks when confronted with potential predators.

Discussion

The main finding of this study was a positive association between evolutionary distinctiveness and flight initiation distance. This finding implies that an important component of biodiversity is related to anti-predator behavior, that ED has evolved in the context of predator-prey interactions, and that FID must have coevolved with ED across evolutionary time scales. This makes sense because coevolutionary interactions between predators and their prey have played a significant role in the evolution of clades of predators and prey [START_REF] Vermeij | The dispersal barrier in the tropical Pacific: implications for molluscan speciation and extinction[END_REF][START_REF] Jablonski | Species selection: theory and data[END_REF][START_REF] Rabosky | Diversity-dependence, ecological speciation, and the role of competition in macroevolution[END_REF]. This is the first study showing that the current anti-predator behavior is correlated with ED scores, which reflects evolutionary history. This result was robust to differences in sampling effort and the potentially confounding effects of body mass, migratory status, the extent breeding ranges and similarity among taxa due to common phylogenetic descent.

The positive relationship between ED and FID implies that "ancestral" species with a relatively long FID would have an effective anti-predator behavior when encountering a predator (Møller and Garamszegi 2012). However, this does not provide evidence that distinct species are predictably on their way to extinction as a result of their behavior and ecology [START_REF] Erwin | An evolutionary basis for conservation strategies[END_REF]. Species with high ED could have rare and derived characteristics, but their current characteristics do not make them less likely to contribute to the future ecological landscape [START_REF] Redding | Evolutionary distinctiveness, threat status, and ecological oddity in primates[END_REF]). On the contrary, species with relatively long FID could have contributed to the formation of their high ED scores, as suggested by lower susceptibility to predation by different species of predators in prey species with long FID (Møller et al. 2008, 2016, Møller and Garamszegi 2012). In other words, FID is a major and reliable predictor of survival prospects.

The presence of predators may play an important role in maintaining efficient antipredator behavior [START_REF] Blumstein | Moving to suburbia: ontogenetic and evolutionary consequences of life on predator-free islands[END_REF], Møller et al. 2016). Here we have shown that speices with relatively high ED values had relatively long FID. As an example, species living on predator-free islands consistently show reduced FID compared to their mainland relatives (Cooper et al. 2014). Because of the absence of predators and the absence of anti-predator behavior on islands, human colonization and invasive alien species on islands have accounted for numerous extinctions, mainly among edemic island species [START_REF] Mcneely | The sinking ark: pollution and the worldwide loss of biodiversity[END_REF][START_REF] Veron | Predicting loss of evolutionary history: Where are we?[END_REF]. Thus, the absence of predators has made island communities vulnerable to predation. Therefore, islands with 'tame' species should be priorities for preserving evolutionary diversity [START_REF] Lovette | Conservation: Evolutionary Values for All 10,000 Birds[END_REF]) because of the potentially high evolutionary diversity on such isolated landmasses (Jetz et al. 2014[START_REF] Tucker | A guide to phylogenetic metrics for conservation, community ecology and macroecology[END_REF].

Body mass was significantly negatively related to ED score and positively related to FID (review in Møller 2015). Body mass has always shown mixed relationships with rates of speciation and extinction, which are probably context dependent [START_REF] Jablonski | Species selection: theory and data[END_REF]). Although species with larger body mass had evolutionary rates marginally slower than those with smaller mass [START_REF] Nunn | Body size effects and rates of cytochrome b evolution in tubenosed seabirds[END_REF]Stanley 1998, Gillman et al. 2012), they are less abundant (Rossberg et al. 2008) and have smaller clutch sizes [START_REF] Jetz | The worldwide variation in avian clutch size across species and space[END_REF]. Relative abundance and encounter rate with individuals from other populations can influence the opportunity for behavioral isolation [START_REF] Butlin | What do we need to know about speciation?[END_REF]) and affect the diversity of close relatives. Still, largebodied birds tend to be more at risk from extinction than small-bodies species [START_REF] Gaston | Birds, body size and the threat of extinction[END_REF]. Thus, the negative correlation between ED and body mass reflects the complex relationship between body mass and taxonomic diversity [START_REF] Orme | Body size does not predict species richness among the metazoan phyla[END_REF].

Although relatively long FID for a give body mass indicates a lower risk of predation, it should not affect the relationship between body mass and ED across species. Large species tend to have long FID mostly to make up for their reduced escape abilities [START_REF] Tobalske | Evolution of avian flight: muscles and constraints on performance[END_REF].

significantly so in the phylogenetic regression. This result was unexpected because migrants are exposed to a greater variety of habitats, predators, parasites and other species than residents. Their interaction with local species and experience under different environmental conditions should contribute to small levels of ED. Nevertheless, geographical gaps could both prevent (Jetz et al. 2014) or promote speciation (Jetz et al. 2012). Seasonal migration under variable predation risks [START_REF] Wilson | The foraging ecology of migratory shorebirds in marine soft-sediment communities: the effects of episodic predation on prey populations[END_REF]) could restrict migratory birds to specific environments throughout life [START_REF] Bensch | Is the range size of migratory birds constrained by their migratory program?[END_REF], especially because migratory birds are highly integrated at various levels, e.g. morphological, sensory, physiological and behavioral (Vá gá si et al. 2016). While migratory species are significantly less likely to have a large range and colonize new breeding areas than resident species [START_REF] Bensch | Is the range size of migratory birds constrained by their migratory program?[END_REF], bird species with the largest ranges are indeed residents [START_REF] Tokeshi | Power fraction: a new explanation of relative abundance patterns in species-rich assemblages[END_REF], that have a greater probability of speciation [START_REF] Gaston | Species-range size distributions: products of speciation, extinction and transformation[END_REF]) and probably small ED values. The correlation between ED and migration disappeared after controlling for the phylogenetic relationship, which could be explained by the fact that sedentary species are more likely to maintain their migratory behavior when speciating [START_REF] Rolland | The top-down mechanism for body mass-abundance scaling[END_REF], even though a strong phylogenetic component with regard to migratory adaptations is unlikely [START_REF] Helbig | Evolution of bird migration: a phylogenetic and biogeographic perspective[END_REF].

The results presented here are based on both migratory and resident water birds across

Europe. The distribution of ED values of 78 water birds is similar with that of all bird species (Fig. 1 and2). Thus the correlation between ED and antipredator behavior is general.

Nevertheless, many top-ED species are isolated on other continents (Jetz et al. 2014) including many islands where predation risk is either absent or negligible (MacArthur and [START_REF] Macarthur | The theory of island biogeography[END_REF]) with leveraged food resources [START_REF] Ebenman | Components of niche width in a territorial bird species: habitat utilization in males and females of the chaffinch (Fringilla coelebs) on islands and mainland[END_REF]. Resident species on islands have shown large differences in morphological and behavioral traits compared with mainland species (e.g. [START_REF] Blumstein | Moving to suburbia: ontogenetic and evolutionary consequences of life on predator-free islands[END_REF], which may result from differences in risk of predation [START_REF] Lima | Predators and the breeding bird: behavioral and reproductive flexibility under the risk of predation[END_REF]) and food abundance [START_REF] Ebenman | Components of niche width in a territorial bird species: habitat utilization in males and females of the chaffinch (Fringilla coelebs) on islands and mainland[END_REF]. It would be interesting to investigate the relationship between ED and FID for such species.

Bird species with relatively high ED scores did not have a consistently large breeding range compared to species with low ED. This is consistent with a study for top-10% ED species by Jetz et al. (2014) . Athough habitat remnants and isolation have been cited as key factors supporting high endemism [START_REF] Kier | A global assessment of endemism and species richness across island and mainland regions[END_REF], and low-ED species are clearly not relict or have diverged recently (Jetz et al. 2012), there may be other important mechanisms for the evolution of species with high ED.

Although species with relatively long FID suffer less from predation (Møller et al. 2008), habitats affected by humans, especially urban habitats, favour species (Møller 2012) and important, but even more so are indirect non-lethal effects (Caro, 2005). The latter results from disturbance by predators and hence can affect habitat choice, sociality, diet and physiology (Lima, 1998;[START_REF] Cresswell | Non-lethal effects of predation in birds[END_REF][START_REF] Cooper | Escaping from predators: an integrative view of escape decisions[END_REF]. Hence indirect effects of predation are often much more important than direct lethal effects (e.g. [START_REF] Creel | Relationships between direct predation and risk effects[END_REF].

Stressful events constitute important ecological and evolutionary forces modulating adaptive responses in natural populations [START_REF] Buchanan | Stress and the evolution of condition-dependent signals[END_REF], and different species have adopted various behavioral strategies to cope with such stress [START_REF] Korte | The Darwinian concept of stress: Benefits of allostasis and costs of allostatic load and the trade-offs in health and disease[END_REF]. As a case in point, oxidative stress has been found to be closely related to life-history and ecological traits [START_REF] Costantini | Oxidative stress in ecology and evolution: Lessons from avian studies[END_REF][START_REF] Selman | Oxidative damage, ageing, and life-history evolution: Where now?[END_REF]. Oxidative stress has attracted much attention recently because it plays a core role in the evolution of optimal investment patterns between reproduction and survival and other fitness components [START_REF] Costantini | From molecules to living systems: Historical and contemporary issues in oxidative stress and antioxidant ecology[END_REF][START_REF] Speakman | Oxidative stress and life histories: unresolved issues and current needs[END_REF].

Numerous processes generate changes in oxidative balance. Antioxidant defenses are decreased by high investment in current reproduction which is paid off in terms of reduced future reproduction and increased mortality [START_REF] Alonso-Alvarez | Increased susceptibility to oxidative stress as a proximate cost of reproduction[END_REF], 2006). For example, oxidative stress may be a physiological cost associated with immune response based on a meta-analysis across 16 studies of 10 bird species [START_REF] Costantini | Does immune response cause oxidative stress in birds? A meta-analysis[END_REF].

Managing oxidative stress is a prominent determinant of life histories, and oxidative stress itself is likely a mediator of life history trade-offs [START_REF] Monaghan | Oxidative stress as a mediator of life history trade-offs: Mechanisms, measurements and interpretation[END_REF].

Strenuous physical activity can increase oxidative stress [START_REF] Herrero | Sites and mechanisms responsible for the low rate of free radical production of heart mitochondria in the long-lived pigeon[END_REF], and many studies of oxidative stress and physical activity have focused on migratory birds.

Although long flights may not seem to influence immune responses for long-distance migrant bird [START_REF] Møller | Parasitism, immunity, and arrival date in a migratory bird, the barn swallow[END_REF][START_REF] Hasselquist | Long flights do not influence immune responses of a long-distance migrant bird: A wind-tunnel experiment[END_REF][START_REF] Møller | The role of parasites in ecology and evolution of migration and migratory connectivity[END_REF], they cause oxidative stress [START_REF] Costantini | Long flights and age affect oxidative status of homing pigeons (Columba livia)[END_REF], and birds up-regulate their antioxidant capacity following stress during endurance flight [START_REF] Jenni-Eiermann | Oxidative stress in endurance flight: An unconsidered factor in bird migration[END_REF]. Thus, physical activity is an important potential cause of oxidative stress. Surprisingly, no study has examined how oxidative stress is related to anti-predator behavior, a central organizing feature in life history and the trade-off between acquisition of energy and predator avoidance [START_REF] Houston | General results concerning the tradeoff between gaining energy and avoiding predation[END_REF].

Individuals optimize the costs of the distance to potential predators balancing these against the costs of flight [START_REF] Ydenberg | The economics of fleeing from predators[END_REF]. Flight initiation distance (FID) is the distance at which an individual takes flight/walks from a potential predator, and hence it reflects this important life history compromise. For example, the risk of predation by sparrowhawks

Accipiter nisus increases with decreasing FID across species (Møller et al., 2008). Likewise, individual barn swallows Hirundo rustica with short FID run higher risks of falling prey to a predator than conspecifics with long FID (Møller, 2014). Thus species with relatively long FID for their body size enjoy a leveraged safety. However, they are also more easily disturbed by potential predators compared to species with relatively short FID. Short and brief aerial flapping flight is metabolically costly, and it may reach 23 times basal metabolic rate in robins Erithacus rubecula (Tatner & Bryant, 1986), which would inevitably increase oxidative stress.

Brains play a key role in predator-prey interactions (Møller, 2015;Samia et al., 2015) as animals use cognitive abilities for assessing the behavior of predators [START_REF] Tyrrell | Sensory systems and escape behavior. Escaping from predators: An integrative view of escape decisions[END_REF]. A range of cognitive benefits has been associated with relatively large brain size [START_REF] Sol | The cognitive-buffer hypothesis for the evolution of large brains[END_REF]. Møller and Erritzøe (2014) found that birds with relatively large brains for their body size avoid the rush when a predator approached. Thus they make the least expensive escape decision after assessment and monitoring of the threat of predation thereby reducing the energy costs of flight (Samia & Blumstein, 2015). However, brain sizes may constitute a trade-off between the costs of brain tissue, for example in terms of antioxidants, and the benefits of increased cognitive abilities, given that neural tissue is energetically expensive [START_REF] Isler | Metabolic costs of brain size evolution[END_REF] and demands large amounts of antioxidants [START_REF] Romero | Oxygen toxicity in the nervous tissue: Comparison of the antioxidant defense of rat brain and sciatic nerve[END_REF][START_REF] Galvá N | Brain size and the expression of pheomelanin-based colour in birds[END_REF]. Individuals may adapt to the costly development of a large brain. Compared with small-brained birds, birds with relatively large brains for their body size may evolve improved resistance to oxidative stress, as they suffer less oxidative damage to lipids and exhibit higher total non-enzymatic antioxidant capacity (Vá gá si et al.,

2016).

The objectives of this study were to test the relationship between FID and oxidative stress under field conditions and to determine how brain size and body mass mediate the relationship between these two factors. A marker of peroxidative damage to lipids (malondialdehyde, MDA) and two markers of antioxidant capacity, total antioxidant status (TAS) and plasma uric acid (UA), were used, relying on a unique and valuable public database [START_REF] Vá Gá Si | Morphological adaptations to migration in birds[END_REF]. As frequent flight take-offs result in high energy consumption (Tatner & Bryant, 1986), and high levels of oxidative stress, we predicted that relatively long FID predisposed certain bird species to elevated oxidative damage (a high MDA level)

and/or an elevated antioxidant level (TAS/UA level). Furthermore, we predicted that a relatively large brain reduced oxidative stress to the brain due to both less energy demanding behavior (relatively short FID; Møller & Erritzøe, 2014) and an efficient defensive machinery against oxidative stress (relatively high TAS/UA level (Vá gá si et al., 2016)).

Materials and methods

Flight initiation distances

FID data were mainly collected by Anders Pape Møller in an area of 100 km 2 in Orsay (48º42'N, 2º11'E), France and an area of 800 km 2 in Northern Jutland (57º12'N, 10º00'E), Denmark during February-September 2006-2016, combined with fewer data from Spain, Norway, Finland, Ukraine and Iceland using a standard protocol (Blumstein, 2006;Møller, 2012). In brief, we approached an individual bird from a distance of 30 m or more and recorded the horizontal distance when the focal bird was moving away either by foot or flight in response to the approaching human. We also recorded the perching height of the bird above the ground. FID was estimated as the Pythagorean distance of the horizontal distance and perching height. A total of 6339 estimates of FID from 72 species with information on redox state were selected from all the records collected.

Redox state markers

Information on three oxidative stress markers (malondialdehyde, MDA, total antioxidant status, TAS and uric acid, UA) was obtained from a previously assembled data set [START_REF] Vá Gá Si | Morphological adaptations to migration in birds[END_REF]. MDA is a widely used marker of oxidative stress which results from lipid peroxidation of polyunsaturated fatty acids [START_REF] Del Rio | A review of recent studies on malondialdehyde as toxic molecule and biological marker of oxidative stress[END_REF]. TAS describes the nonenzymatic antioxidant defense on the dynamic equilibrium between pro-oxidants and antioxidants in the plasma compartment [START_REF] Ghiselli | Total antioxidant capacity as a tool to assess redox status: Critical view and experimental data[END_REF]. UA is a potent antioxidant for birds [START_REF] Tsahar | The relationship between uric acid and its oxidative product allantoin: A potential indicator for the evaluation of oxidative stress in birds[END_REF] and has been found to demonstrate substantial interspecific differences in constitutive antioxidant capacity across 92 bird species [START_REF] Cohen | Measuring circulating antioxidants in wild birds[END_REF].

Despite concerns about intraspecific variation, this variation can be neglected in comparisons among species as the redox state markers were found to be species-specific both for this dataset (Vá gá si et al., 2016) and previous studies [START_REF] Cohen | Interspecific associations between circulating antioxidant levels and life-history variation in birds[END_REF].

Brain mass and body mass

Information on brain mass came from an extensive database on birds from Denmark recorded by J. Errizøe in a consistent way during 1960-2013 (Møller & Erritzøe, 2014).

Previous analyses have shown a high degree of consistency between mean estimates based on this database [START_REF] Garamszegi | Coevolving avian eye size and brain size in relation to prey capture and nocturnality[END_REF] and other databases (Samia et al., 2015). Brain mass was strongly positively correlated with body mass (log10-transformed brain size strongly correlated with log10-transformed body mass, r 2 = 0.85, P < 0.01). However, multiple regression is the best approach to control for undesirable confounding effects coefficients were calculated for all relationships in the best model using PGLS analyses on standardized variables (mean of 0 and SD of 1). Our final path analyses were made up of three PGLS models. All statistical analyses were carried out in R 3.4.2 (R Core Team, 2017). 1A and1C). In the multivariate model, we did not find a significant relationship between TAS and FID/brain size (Table 1B). These results were robust to potentially confounding variables, body mass, sample size and similarity due to common phylogenetic descent.

Results

Mean

The best phylogenetic path models suggested that body mass had a significant direct effect on oxidative stress, FID and brain size (Fig. 3). FID mostly affected the levels of MDA and UA indirectly through their relationship with body mass (Fig. 3). Brain size mostly affected the levels of MDA indirectly through its relationship with body mass (Fig. 3A), but significantly directly affected UA (Fig. 3B). Phylogenetic path analyses showed relative consistency in path coefficients across two different oxidative stress variables, MDA and UA. FID and brain size did not show any significant path correlation in either path analysis,

although brain size showed a potential effect on FID in the path models with MDA (estimate = -0.212, P = 0.509).

Discussion

The main finding of this study was that mean flight initiation distance of different species of birds was positively correlated with species-specific MDA and UA levels and mediated through their relationship with body mass. This result was robust to differences in sample size and similarity due to common phylogenetic descent. It suggests that frequent take-offs during flight from a given number of potential predators could be a mechanism that affects the concentration of pro-oxidants, and it could select for an elevated level of antioxidants.

A few studies have investigated the physiological mechanisms of escape. Some have considered the physiological costs of monitoring (Cooper & Blumstein, 2014), while others have focused on initiated flights finding that FID, after adjustment for body mass, increased with increasing basal metabolic rate (BMR) across 76 bird species (Møller, 2009). This is presumably because predation risk imposes selection favoring wariness requiring higher BMR as a compensation. Species that allow close proximity of a potential predator have high hematocrit for their body size, which represents the ability for high oxygen transport allowing for high performance during rapid take-offs (Møller et al., 2013). As a measurement of trade-off between risk of predation and other activities, FID is consistent among different conditions [START_REF] Ydenberg | The economics of fleeing from predators[END_REF][START_REF] Giraldeau | Social foraging theory[END_REF]Carrete & Tella, 2010). Although a flush caused by a brief approach by a potential predator may last only a few seconds, the accumulated effect can still be substantial because even brief aerial flapping flight may result in 23 times basal metabolic rate in robins (Tatner & Bryant, 1986).

For a given abundance of potential predators, individual prey with relatively long FID should experience greater accumulated energy costs than individuals with short FID because they are more easily disturbed. Species with long FIDs for their body size also developed relatively large wing areas and large aspect ratios, and hence relatively low costs of flight and maneuverability (Møller et al., 2013), expected as a consequence of selection caused by the energetic costs of FID. Thus early flight from predators is not only energetically expensive, but also associated with higher oxidative stress. It would be inspiring and important to include indicators of oxidative stress into such analyses considering antipredator behavior.

The degree of lipid peroxidative damage measured as MDA and nonenzymatic antioxidant defense mechanism represented by UA showed consistency in their correlation with body mass and FID. Previous study of seven bird species found that cardiac muscle malondialdehyde concentration was negatively related to body mass [START_REF] Szabó | Body size related adaptations of the avian myocardial phospholipid fatty acyl chain composition[END_REF], indicating a progressive myocardial lipid peroxidation in smaller-bodied species. These results are consistent with the fact that high antioxidant levels may reflect less control of free radical production [START_REF] Barja | Aging in vertebrates, and the effect of caloric restriction: A mitochondrial free radical production DNA damage mechanism?[END_REF], and effective control is a function of lowered membrane gradients rather than upregulating antioxidants [START_REF] Cohen | Interspecific associations between circulating antioxidant levels and life-history variation in birds[END_REF]. However, we did not find a significant correlation between TAS and FID, or body mass or brain size.

This could be due to the synergistic and antagonistic interactions among different constituents of non-enzymatic antioxidants [START_REF] Monaghan | Oxidative stress as a mediator of life history trade-offs: Mechanisms, measurements and interpretation[END_REF], and that adaptation could be an alternative explanation for high antioxidant defense levels [START_REF] Clausen | Prevention of cognitive deficits and brain oxidative stress with superoxide dismutase/catalase mimetics in aged mice[END_REF].

can help us better interpret ecological field studies [START_REF] Romero | Physiological stress in ecology: Lessons from biomedical research[END_REF].

In conclusion, we show for the first time that free-living birds with relatively short FID for their body mass experienced more peroxidative damage to lipids (malondialdehyde, MDA), and such species had an elevated component of antioxidant capacity (uric acid, UA). These relationships were mostly mediated through the relationship between FID and body mass. Table 1 PGLS models of the relationship between log10-transformed flight initiation distance (FID), oxidative damage/antioxidant level, brain size and body mass, respectively, weighted by sample size for species of birds. The model for malondialdehyde (MDA) had the statistics F3, 68 = 4.53, r 2 = 0.12, P < 0.0001, the model for total antioxidant status (TAS) had the statistics F3, 68 = 2.83, r 2 = 0.01, P = 0.7398 and the model for uric acid (UA) had the statistics F3, 67 = 5.03, r 2 = 0.18, P < 0.0001. P-values in bold font are statistically significant at the 0.05 level. Flight initiation distance (FID) is defined as the distance at which animals take flight from approaching threats [START_REF] Hediger | Zur Biologie und Psychologie der Flucht bei Tieren[END_REF]Blumstein, 2003). This behavioral trait has been used as a surrogate for anti-predator or fear-avoidance behavior in many ecological studies (e.g.

Response

Møller 2008a

; [START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF][START_REF] Legagneux | European birds adjust their flight initiation distance to road speed limits[END_REF]Møller et al. 2013).

However, the majority of studies of escape behavior in birds focused on the influence of external or interspecific factors affecting behavioral responses: the direction of approach by predators (Møller and Tryjanowski 2014), intruder starting distance (Blumstein, 2003), population density [START_REF] Mikula | Pedestrian density influences flight distances of urban birds[END_REF], urbanization (Samia et al., 2017), road speed limits [START_REF] Legagneux | European birds adjust their flight initiation distance to road speed limits[END_REF], insular distribution (Cooper et al., 2014), predator-prey interactions (Møller, 2008b), spatial gradients of predator abundance (Dí az et al., 2013) or daytime and season when FID was measured [START_REF] Piratelli | Factors affecting escape distance in birds[END_REF].

Currently we know that large species have long FIDs, because larger species need more time to get airborne and hence avoid capture [START_REF] Hemmingsen | The relation of shyness (flushing distance) to body size[END_REF]Ferná ndez-Juricic et al., 2006;Møller, 2008c;[START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF]. We know that birds from rural areas tend to escape earlier than birds from urban areas, being less tolerant of humans, probably because urban birds live under lower predation risk than their rural counterparts (Møller, 2015;Samia et al., 2017). Finally, we know that behavioral responses of animals to human approach such as FID can be useful for conservation purposes, namely management of disturbance, especially in human-dominated environments [START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF]. But we know very little about the intraspecific factors which can be involved in any variation in FID. Group size has also been suggested to be another important prey trait that influences escape decisions (Samia et al., 2017). But this study, even if considering explicitly the relation between FID and the number of individuals of the same species around a focal individual, mainly focused on comparisons between habitats rather than flock sizes in gregarious and non-gregarious species. Møller (2015) reviewed the literature on FID in birds and showed that sociality (directly related to group size) had an intermediate mean effect size of 0.26 on FID. There is even less information available for other classes of animals [START_REF] Cooper | Escaping from predators: an integrative view of escape decisions[END_REF]. The effect of flock size on animal fear is important, because fear responses link individual behavior to social factors, such as the number of conspecifics in a flock, opening the perspective for possible cascade effects on fear reactions in birds.

Under classical ecological models of predation risk, which predict a decrease in individual risk when group size increases (Pulliam, 1973;[START_REF] Alexander | The evolution of social behavior[END_REF], we would expect a reduction in FID among individuals in large groups through the dilution effect (Pulliam, 1973;[START_REF] Roberts | Why individual vigilance declines as group size increases[END_REF][START_REF] Ferná Ndez-Juricic | Factors affecting intra-and interspecific variations in the difference between alert distances and flight distances for birds in forested habitats[END_REF]. However, the opposite response could also be expected (increasing FID with increasing flock size) because of the social transmission of fear responses [START_REF] Griffin | Social learning about predators: a review and prospectus[END_REF], and early detection of predators in large groups [START_REF] Stankowich | Fear in animals: A meta-analysis and review of 2634[END_REF][START_REF] Hingee | Flights of fear: A mechanical wing whistle sounds the alarm in a flocking bird[END_REF]. Awareness or nervous reactions can be positively related to flock size because of the higher vigilance (effect of many eyes scanning for predators) (Pulliam, 1973). Thus, under threat, individuals in large flocks should react more rapidly than solitary individuals or individuals in small groups, as a consequence of cascade effects or contagious alertness.

Despite that the literature on fear responses and sociality is limited, cooperative breeders were shown to be more nervous than species with other breeding systems (Blumstein, 2006), which would support the second hypothesis. In fact, a ground-breaking study conducted by Laursen et al. (2005) reported intermediate to large effect sizes for intraspecific relationships between FID and flock size in different species of waterbirds with FID being longer for larger flocks. These findings are inconsistent with dilution effects, because if each individual in a flock enjoyed a smaller risk, we should expect a shorter FID in larger flocks. In contrast, the results are consistent with effects of many eyes scanning for the presence of a predator, although differences in phenotypic composition of differently sized flocks may be an alternative explanation for these findings. Effect sizes for the interspecific relationship between FID and coloniality were all small (Møller, 2008c). Finally, Tä tte et al. (2017) showed that flock size predicts FID, but not the distance fled, implying that it is the perception of risk rather than the actual distance moved during an escape that is the determinant of differences in FID among flocks of different size.

Gregariousness is common in nature and can be defined as the tendency to live in flocks [START_REF] Miller | The significance of the gregarious habit[END_REF]. A flock is a term used to define any aggregation of homogenous individuals, regardless of size or density [START_REF] Emlen | Flocking behavior in birds[END_REF]. As pointed out by Miller in 1922, probably the most obvious advantage of gregarious behavior in birds is that it affords a multiplicity of eyes, increasing the chance of sighting a potential predator. Then, any defensive measures can be taken early, increasing the probabilities of success of escape against the risk [START_REF] Miller | The significance of the gregarious habit[END_REF].

We hypothesized that FID in response to human approach would be longer in more social species. The ecological rationale for this expectation is that vigilance and FID increases with group size because of the many eyes effect, and a nervous state can be transmitted more easily when there are many individuals in a flock. However, this process should be more predominant in social or gregarious than in solitary species, because gregarious species may be better at exchanging information with other individuals in the group than non-gregarious species. As a consequence, the aim of this study was to test if FID in birds increases with the number of conspecifics (flock size), focusing on differences between gregarious and non-gregarious species.

Methods

Study area and flight initiation distance

Data were collected during April-September 2015 using a standard protocol (Blumstein, 2006;Samia et al., 2017). Data were collected in urban and adjacent rural areas of eight cities in eight European countries: Czech Republic, Denmark, Estonia, Finland, France, Hungary, Poland, and Spain (Fig. 1; ESM, Table S1). We used a paired study design with one urban and one rural site (habitat type) in each study location. The distance between each pair of urban and rural site was always shorter than 20 km. The sites classified as "urban"

were characterized by areas with multi-story buildings or by areas with single-family houses (suburban areas). The sites classified as "rural" were areas dominated by open farmland with scattered houses (Samia et al., 2017). For the definition of urban and rural habitats we followed the definitions provided in [START_REF] Marzluff | Avian ecology and conservation in an urbanizing world. 1st edn[END_REF]. Urban habitats were defined as areas with at least 50% of built-up area, building density >10 buildings/ha and, a residential human density >10 humans/ha. Rural habitats were defined as the areas with 5-20%builtup areas, a building density<2.5 buildings/ha, and residential human density between 1 and 10 humans/ha [START_REF] Marzluff | Avian ecology and conservation in an urbanizing world. 1st edn[END_REF]. Observers used binoculars to identify birds that were foraging or engaged in "relaxed behavior" (i.e., roosting or preening). Highly vigilant or obviously alarmed individuals were not approached. Furthermore, data from breeding sites (e.g. from gull colonies) or anthropogenic feeding sites (e.g. rubbish dumps) were not collected. Each individual bird was approached in a straight line by the observer walking at a constant speed (0.5m/s).

Flight initiation distance (FID) was measured as the distance between the observer and the point where the individual bird began to flee (see more details in Samia et al. 2017). Only bird species detected on the ground were considered. [START_REF] Sol | Risk-taking behavior, urbanization and the pace of life in birds[END_REF] showed that species with more than 10 recorded cases per study site provided reliable estimates of FID. Here, applying a more conservative approach and trying to focus on the most common species, we only selected bird species with more than 50 observations of FID, so also any potential effect of starting distance should be considerably alleviated.

Flock size was defined as the number of aggregated individuals of the same species, implying that individuals in flocks are closer to each other than individuals that are not in flocks.

Ecological variables: Trophic guild, body mass and gregariousness

For each bird species recorded in this study, we included the following information: trophic guild or diet (main type of food consumed, following the bird traits of feeding ecology provided in [START_REF] Pearman | Phylogenetic patterns of climatic, habitat and trophic niches in a European avian assemblage[END_REF]. All species were classified in five main categories as, granivorous, granivorous-insectivorous, insectivorous, carnivorous and carrion-eater (ESM, Table S2). Body mass for each species was obtained from the same source [START_REF] Pearman | Phylogenetic patterns of climatic, habitat and trophic niches in a European avian assemblage[END_REF] and this variable was log-transformed to fit normality.

All bird species were classified as gregarious or non-gregarious during the breeding and the non-breeding season, using information from the Handbook of the Birds of the Western Palearctic [START_REF] Cramp | The Birds of the Western Palearctic[END_REF]) (ESM, Table S2). Birds were classified as "gregarious"

when species have shown gregarious activities at least in one period of the year (breeding or non-breeding period) (ESM, Table S2). There was a positive correlation between the gregariousness P = 0.020), implying that species that were gregarious during breeding also tended to be gregarious during the non-breeding season. We decided to group breeding and non-breeding gregarious species, because we assumed that cognitive capacity for gregariousness, i.e., the capacity to communicate with other individuals from the same species, is a species-specific trait that may manifest either during breeding or wintering periods but is present all the time.

Bird species were finally classified in quantiles on the basis of their body mass using the 'ggtool' package for R [START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF]. The classification of bird species with respect to body mass quantiles was used in some statistical analyses, in order to make easier the comparison of bird species of different size.

Statistical analyses

The average values of FID and flock size between groups based on species-specific gregariousness were compared using the standard nonparametric Wilcoxon test [START_REF] Triola | Elementary Statistics[END_REF].

We used Generalized Linear Mixed Models (GLMM) [START_REF] Bolker | Generalized linear mixed models: a practical guide for ecology and evolution[END_REF] to analyze the changes in FID behavior of bird species in relation to flock size. Models were fitted separately for non-gregarious and gregarious bird species, using the package 'lme4' [START_REF] Bates | Fitting linear mixed-effects models using lme4[END_REF]. We found that FID (response variable) was normally distributed, after having explored the distribution of the variable [START_REF] Box | An analysis of transformations[END_REF] using the package 'MASS' [START_REF] Venables | Modern Applied Statistics with S. 4th edn[END_REF]. Two series of models were run: First controlling for the phylogenetic signal among species and then non-phylogenetic models using flock size as a fixed factor and other variables as random factors.

In the phylogenetic models, to control for the phylogenetic relationship among species, we used phylogenetic generalized least square (PGLS) on regression models to analyze the changes in FID behavior of bird species in relation to flock size. Models were fitted separately for non-gregarious and gregarious bird species, using the package 'ape' (Paradis et al., 2004), 'nlme' (Pinheiro et al., 2017) and the function gls with correlation equals consensus tree. We extracted the phylogenetic relationship for all bird species from the phylogeny available on line (Jetz et al. 2012(Jetz et al. , 2014) ) and obtained consensus phylogenies for both gregarious and non-gregarious species from 100 random trees with Mesquite (Maddison & Maddison, 2017). Different populations of the same species from different countries and habitats were defined with a relatively different branch length of 1E-19 just to fit the models. We weighted models by sample size [START_REF] Garamszegi | Effects of sample size and intraspecific variation in phylogenetic comparative studies: A meta-analytic review[END_REF]Garamszegi, 2014).

In the non-phylogenetic models, flock size and habitat were entered as predictor variables, while the cities, body mass quantiles, diet type and bird species were all included as random factors. The use of random factors permits to focus on the main effects of focused predictors (flock size and habitat), removing any potential effect associated to other factors. The inclusion of the cities controlled for possible consistent differences among cities where data were collected, while inclusion of body mass quantiles reduced any effect associated with a strong correlation between FID and body mass (Møller et al., 2016). Moreover, because there were multiple observations for each species, and because a shared evolutionary history makes data statistically dependent [START_REF] Garamszegi | Nonrandom variation in within-species sample size and missing data in phylogenetic comparative studies[END_REF], the addition of species as random factor alleviates any potential bias related to phylogenetic dependence among

species. An additional GLMM with the same structure as for gregarious birds was run, considering only gregarious species, which have flocks smaller than 11 individuals (equal to the maximum number of individuals recorded for non-gregarious birds).

Because AICc converges to AIC with larger sample sizes, it is recommended to always use AICc to select the best model [START_REF] Burnham | Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach[END_REF]. When comparing a series of models, the one with the lowest AICc is considered to be the most parsimonious or best model. We also calculated an Akaike weight (wi), or model probability, for each model, considering that the wi sum to 1 for the whole set of models. The wi is the probability that model i would be selected as the best-fitting model if the data were collected again under identical circumstances [START_REF] Burnham | Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach[END_REF]. The model selection and multimodel associated with urban habitats. The list of evaluated models, with the number of predictors considered, delta AIC values and AIC weights for each one is provided in Table S3 of the Electronic Supplementary Material.

The same significant positive association between FID and flock size was confirmed when standardizing the analyses to similar range of flock sizes for both gregarious and nongregarious species, i.e., focusing only on gregarious bird species with flocks smaller than 11 individuals (ESM, Table S4). Additionally, the pattern was persistent even when modeling separately the six more frequent gregarious bird species: Columba livia, Columba palumbus, Corvus monedula, Corvus frugilegus, Passer domesticus, Sturnus vulgaris (ESM, Table S5).

Discussion

The main finding of this study was that FID increased with flock size in gregarious species, while that was not the case in non-gregarious species. This pattern was persistent even within species, when focusing on individuals of the six more frequent gregarious birds.

Interestingly, these effects were independent of body mass and geographic area where data were collected (city), as well as the phylogenetic signal among species. Indeed Møller (2015) in a meta-analysis of all studies of FID in birds showed a mean effect size estimated as Pearson's product-moment correlation coefficient of 0.39 for body mass thus accounting for 15% of the variance, 0.62 for urbanization (urban vs. rural) accounting for 38% of the variance and 0.26 for sociality only accounting for 7% of the variance. In fact, the effect size of 0.24 reported for gregarious species was very similar to that of 0.26 for sociality reported by Møller (2015). Type of diet was unrelated to the FID of non-gregarious birds in the present study, while in gregarious birds we found that insectivorous species tend to have the shortest FID. Additionally, we found a positive association between FID and body mass (especially marked in non-gregarious species), and we confirmed in all models that FID tends to decrease with urban habitat when compared with rural areas. These two results are confirming previous studies [START_REF] Warnes | A review of flightinitiation distances and their application to managing disturbance to Australian birds[END_REF]Dí az et al., 2013;Møller et al., 2016;Samia et al., 2017). The association between FID and latitude showed a less clear pattern.

Finally, the positive correlation between FID and body mass showed a more pronounced slope for insectivorous, carrion-eaters and granivorous-insectivorous birds than other categories. These effects can be explained by the fact that gregariousness is more prominent in species relying on unpredictable food supply such as superabundant carrion and insects between FID and body mass to be more pronounced in more gregarious species.

The current study tests the two hypotheses listed in the Introduction; the dilution effect [START_REF] Stankowich | Fear in animals: A meta-analysis and review of 2634[END_REF] and the many eyes effect [START_REF] Stankowich | Fear in animals: A meta-analysis and review of 2634[END_REF][START_REF] Hingee | Flights of fear: A mechanical wing whistle sounds the alarm in a flocking bird[END_REF]. Indeed, larger flocks have more individuals scanning for predators, but larger flocks also result in stronger dilution effects because the risk is smaller for each individual in a larger flock. Here, using mainly Passeriformes, we have shown a clear positive relationship between FID and flock size, which supports the many eyes effect hypothesis. A similar general pattern was previously reported by Laursen et al. (2005) for waterbirds, while other study suggested no influence of flock size on FID for the particular case of black swans Cygnus atratus (Guay et al., 2013).

The present study of mainly passerine birds compares well with that by Laursen et al. (2005) for waterbirds comprised of geese, ducks, waders and gulls. In fact, both studies have very similar effect sizes despite the taxa being completely different and the association with urbanization being restricted to the present study. However, hunting activities affected FID in the study by Laursen et al. (2005), but not in the present study. Indeed Laursen et al. (2005) showed an effect of flock size on FID for nine waterbird species in fall, when hunting is common, while only two species showed a significant relationship between FID and flock size in spring when hunting ceased.

Longer FID in larger flocks of a given species implies that individuals on average run a higher risk in small flocks. This could either be due to such larger flocks being composed of individuals of lower phenotypic quality, or that individuals in small flocks with short FID run higher risks of mortality. Indeed, Møller (2014) has shown that barn swallow Hirundo rustica individuals with short FID are more likely to be caught by sparrowhawks Accipiter nisus. In addition, bird species with shorter FID were more vulnerable to get caught by raptors (Møller et al. 2008) or cats Felis catus (Møller et al. 2010) and to be killed by cars (Møller et al. 2011). We are unaware of any other studies showing such effects.

We classified the species as gregarious or not because we assumed that gregarious species would encounter conspecifics more often than non-gregarious species [START_REF] Emlen | Flocking behavior in birds[END_REF]. For this reason, we can hypothesize that individuals of gregarious species are better adapted at exchanging information with each other than are individuals of non-gregarious species.

Thus, individuals belonging to gregarious species would experience a trade-off between foraging (or resting) under the safety of the presence of many conspecifics and having long FIDs, or having short FIDs in the presence of few conspecifics (Laursen et al., 2005).

Accordingly, FID was only positively related to flock size in gregarious, but not in non-gregarious species (Figs. 3 and4). Thus, the effect of sociality on FID was only obvious in gregarious species, while the effect for non-gregarious species was close to zero. However, a potential alternative explanation for this pattern is that relatively small flocks of nongregarious species might not be effective in increasing detection of predators as large flocks.

Therefore, we compared FID for gregarious bird species with FID for small flocks (these flocks should be more similar to the small flocks of non-gregarious species) (ESM, Table S3), confirming the same positive association between FID and flock size. An additional confirmation of the robustness of this result is that using two different modelling approaches the pattern of this positive and significant association was the same. Therefore, the association between FID and flock size was restricted to gregarious bird species.

We explicitly recorded FID observations in urban and rural habitats. While previous studies have shown consistently longer FIDs in rural than in urban habitats (e.g. Samia et al.

2017), we are only aware of a single other study investigating the independent effects of rural vs. urban habitats and flock size on FID (Tä tte et al., 2018). The latter study also found a similar effect of flock size in rural and urban habitats.

The present study suggests a number of future prospects. For instance, we can point out that every future study on the FID of gregarious birds has to explicitly consider the number of individuals around the bird observed. We hypothesize that experimental change in sociality will have effects on FID. Indeed, [START_REF] Laursen | Dynamic group size and displacement as avoidance strategies by eiders in response to hunting[END_REF] have shown that flock size changes adaptively in response to intense hunting. We predicted that such changes in immediate risk will be accompanied by similarly directed changes in FID. Finally, we hypothesize that changes in flock size can be experimentally manipulated by changing food availability with consequences for change in FID.

In conclusion, we have shown that FID increases with flock size, but only in gregarious, and not in non-gregarious species. These findings imply a role of sociality for risk taking behavior and hence for social organization. Our conclusions have broad biological implications, especially considering the role of sociality and gregariousness as possible factor facilitating animals to colonize urban environments and to adapt to these humanimpacted environments. S2). Envelopes around lines are 95% confidence intervals. Colors indicate bird family, and circle size is proportional to body mass of birds (g).

Envelopes around lines are 95% confidence intervals. i Coloration du plumage Prey peut é viter la pré dation en se dissimulant dans l'environnement afin que les pré dateurs ne parviennent pas à les trouver. De nombreuses é tudes ont abordé les avantages anti-pré dateurs du plumage cryptique chez les adultes [START_REF] Götmark | Anti-predator effect of conspicuous plumage in a male bird[END_REF][START_REF] Götmark | Bright male plumage and predation risk in passerine birds: Are males easier to detect than females?[END_REF][START_REF] Slagsvold | Predation favours cryptic coloration in breeding male pied flycatchers[END_REF], et la pré dation est une force sé lective en raison des avantages potentiels de la coloration du plumage (p. 1986). Chez certaines espè ces, les individus changent de couleur selon les saisons [START_REF] Slagsvold | Variation in plumage colour of the great tit Parus major in relation to habitat, season and food[END_REF][START_REF] Steen | Cryptic behaviour in moulting hen willow ptarmigan Lagopus l. lagopus during snow melt[END_REF] et / ou reproducteurs [START_REF] Slagsvold | Predation favours cryptic coloration in breeding male pied flycatchers[END_REF], ce qui fournit des preuves additionnelles, mais non concluantes, de ré duction du pelage ou du plumage. risque de pré dation. La ressemblance des couleurs est plus bé né fique chez certaines espè ces que chez d'autres [START_REF] Cott | Adaptive coloration in animals[END_REF]. Par exemple, les espè ces nocturnes telles que les hiboux doivent ê tre cryptiques car elles ont tendance à rester immobiles et à dormir pendant la journé e, comme le suggè re [START_REF] Cott | Adaptive coloration in animals[END_REF]. Cependant, mê me aprè s des recherches de longue duré e, il existe encore peu de preuves systé matiques indiquant que la coloration du une partie importante de la straté gie anti-pré datrice des individus qui ré duit les coûts de ré ponse aux fausses alarmes (Treisman, 1975[START_REF] Koops | Reliability and the value of information[END_REF], Magrath et al., 2007). Plus la distance entre la proie et le pré dateur est courte, plus grande est la probabilité que la proie soit tué e car l'é vasion prend du temps avant de commencer alors que le pré dateur se rapproche. Un individu qui n'a pas ré ussi à s'é chapper face à un pré dateur est mort. Une fuite inefficace pourrait causer des blessures à la proie, mê me si cela peut impliquer la survie [START_REF] Dickey | Chemically mediated effects of injured prey on behavior of both prey and predators[END_REF][START_REF] Heithaus | Shark-inflicted injury frequencies, escape ability, and habitat use of green and loggerhead turtles[END_REF] et mê me les possibilité s de reproduction subsé quentes s'ils ont des queues ou des ailes endommagé es [START_REF] Fitzpatrick | Magpies' tails: Damage as an indicator of quality[END_REF][START_REF] Jennions | Variation in mate choice and mating preferences: A review of causes and consequences[END_REF]. L'é vasion semble ê tre une action simple: Tant que la proie court au moment où un pré dateur est dé tecté , la proie atteindra la probabilité maximale de survie de cette rencontre. La ré ponse d'un individu à un pré dateur potentiel peut faire l'objet de compromis [START_REF] Ydenberg | The economics of fleeing from predators[END_REF][START_REF] Blumstein | Assessment and decision making in animals: A mechanistic model underlying behavioral flexibility can prevent ambiguity[END_REF][START_REF] Cooper | Optimal flight initiation distance[END_REF] parce que les proies, en plus d'é viter d'ê tre poursuivies, doivent aussi se nourrir et se reproduire. Le vol direct implique la fin / le changement de comportement en cours, ce qui signifie abandonner les avantages potentiels. Mê me si les individus se reposent lorsqu'ils rencontrent un pré dateur, quitter immé diatement les amè ne à consommer plus d'é nergie (Tatner et Bryant, 1986), abandonner l'habitat d'alimentation potentiel [START_REF] Brown | Vigilance, patch use and habitat selection: Foraging under predation risk[END_REF], et par la suite ré duire leur forme physique. Ainsi, les animaux doivent optimiser la distance à laquelle ils commencent à s'é chapper, de sorte que les avantages de rester en place sont mis en balance avec les coûts de vol (figure 1, [START_REF] Ydenberg | The economics of fleeing from predators[END_REF]. Cette distance reflè te le compromis du cycle de vie entre le risque de pré dation et les avantages de la recherche de nourriture. Tous les animaux fuient les pré dateurs et les humains potentiels, et la faune ré agit aux humains de la mê me maniè re qu'aux pré dateurs (Frid et Dill, 2002). Les é vé nements de pré dation suivent gé né ralement une sé quence: rencontre, dé tection, identification, approche, assujettissement et consommation du point de vue des pré dateurs [START_REF] Endler | Interactions between predators and prey. Behavioural ecology: An evolutionary approach[END_REF]. Pour cette é tude de la distance de fuite, les humains sont les pré dateurs pré sumé s de la rencontre.

Quand un oiseau individuel est initialement vu, il est identifié aux espè ces. La distance de dé part (SD) est la distance à laquelle un humain commence à s'approcher de l'individu cible, et la distance d'alerte (AD) est la distance à laquelle l'individu cible montre un comportement d'alerte clair (figure 2). La distance d'initiation de vol (FID) est la distance à laquelle un animal prend son envol lorsqu'il est approché par un humain. La rencontre est interrompue à ce moment et la distance parcourue (DF) enregistre ce qui se passe aprè s. La SD est positivement corré lé e avec le FID (par exemple [START_REF] Blumstein | Avian risk assessment: Effects of perching height and detectability[END_REF][START_REF] Cooper | When and how do predator starting distances affect flight initiation distances[END_REF], 2008).

Cette relation est d'abord contrôlé e mathé matiquement (la FID ne peut ê tre é gale ou infé rieure à SD), mais elle a aussi une composante biologique [START_REF] Dumont | Flight initiation distance and starting distance: Biological effect or mathematical artefact[END_REF]. Les animaux ont un coût attentionnel pour la surveillance continue d'un pré dateur qui s'approche (Blumstein, 2003, Samia et Blumstein, 2015). la taille de la personne qui s'approchait (Møller, 2008a).

Il existe une abondante litté rature sur la mé thodologie des é tudes de FID, et ils ont trouvé une forte relation positive entre FID enregistré e par diffé rents observateurs, cohé rence temporelle de FID dans les estimations de diffé rentes anné es et FID cohé rente entre diffé rents sites (par exemple Blumstein, 2003;., 2003, Møller et al., 2008, Møller & Erritzøe, 2014). Dans les é tudes qui ont suivi des individus marqué s, on a vé rifié que le FID avait une ré pé tabilité é levé e (Carrete et Tella, 2010, 2013), ce qui est une mesure de la cohé rence intra-individuelle. Ainsi, le FID est une mesure fiable du risque ré el de pré dation. La litté rature sur le FID, mettant l'accent sur les oiseaux (Møller, 2015), les mammifè res [START_REF] Stankowich | Mammals. Escaping from predators: An integrative view of escape decisions[END_REF] et les lé zards [START_REF] Cooper | Reptiles. Escaping from predators: An integrative view of escape decisions[END_REF], ont identifié une varié té de facteurs corré lé s avec le FID [START_REF] Cooper | Escaping from predators: an integrative view of escape decisions[END_REF]. dans le tableau 1. Le FID, en tant qu'indicateur du comportement anti-pré dateur, est é galement connu pour ê tre hé ritable et faire l'objet d'une sé lection directionnelle (Dall et al., 2004;Blumstein et al., 2010;Møller & Nielsen, 2010;Bize et al. ., 2012).

III L'hé ritabilité du comportement d'é vasion

Le comportement d'é chappement est la derniè re é tape du comportement anti-pré dation avant la capture. L'individu est susceptible de faire face à la mort une fois que sa fuite é choue. Par consé quent, un comportement d'é vasion efficace devrait avoir une forte composante hé ré ditaire, car son lien fort et direct avec la survie offre des possibilité s limité es de «pratique». La plupart des caractè res ont une base gé né tique quantitative avec la progé niture ressemblant à leurs parents dans le phé notype. La ré pé tabilité est une limite supé rieure de à la sé lection [START_REF] Falconer | Introduction to quantitative genetics[END_REF]. Ainsi, des estimations d'hé ritabilité sans biais et des estimations de sé lection peuvent ê tre utilisé es pour pré dire la ré ponse micro-é volutive.

Ainsi, si par exemple l'intensité de la sé lection augmente, nous devrions ê tre en mesure de pré dire l'augmentation du phé notype en raison de la ré ponse à la sé lection. Gé né ralement, le comportement d'é chappement est une ré ponse à l'environnement et est sujet à la sé lection naturelle. Moins d'é tudes ont é tudié l'hé ritabilité du comportement. Le comportement luimê me est le ré sultat d'une performance globale en ré ponse à divers facteurs [START_REF] Sih | Behavioral syndromes: An ecological and evolutionary overview[END_REF][START_REF] Bonduriansky | Nongenetic inheritance and its evolutionary implications[END_REF], incluant la ré gulation physiologique [START_REF] Ricklefs | The physiology/life-history nexus[END_REF], la capacité cognitive (Griffin et al. Cole et al., 2012) et les contraintes morphologiques [START_REF] Foster | Determinants of lizard escape performance: Decision, motivation, ability, and opportunity. Escaping from predators: An integrative view of escape decisions[END_REF]. Pour de nombreuses espè ces, les parents et leur progé niture vivent dans des territoires gé ographiquement adjacents (si ce n'est les mê mes) et ils sont susceptibles de se comporter de la mê me faç on (Wilson, 1998). Les effets sur la maternité peuvent é galement jouer un rôle important en affectant les ré actions comportementales de la progé niture à l'environnement, y compris l'environnement maternel [START_REF] Eising | Avian mothers create different phenotypes by hormone deposition in their eggs[END_REF]. En outre, l'apprentissage et l'imitation peuvent ê tre d'autres explications des similitudes de comportement entre les gé né rations, qui peuvent provenir des soins parentaux aussi bien que des pairs [START_REF] Koolhaas | Coping styles in animals: Current status in behavior and stress-physiology[END_REF][START_REF] Hamm | Do birds of a feather flock together? The variable bases for African American, Asian American, and European American adolescents' selection of similar friends[END_REF].

Il y a peu d'é tudes qui dé montrent que le comportement d'é vasion est hé ritable, car il est difficile d'é tudier l'hé ritabilité du comportement d'é vasion dans des conditions de terrain.

Les pé toncles juvé niles, Argopecten purpuratus, pré sentaient une hé ritabilité significative et une corré lation gé né tique significative entre plusieurs caractè res de ré ponse à l'é chappé e en utilisant le modè le de fraie complè te / demi-fratrie [START_REF] Brokordt | Heritability and genetic correlations of escape behaviours in juvenile scallop Argopecten purpuratus[END_REF]. Les couleuvres rayé es Thamnophis ordinoides ont montré des hé ritabilité s et des corré lations gé né tiques significatives parmi les caractè res d'é chappement en utilisant une analyse gé né tique quantitative basé e sur le pedigree [START_REF] Brodie | Genetic correlations between morphology and antipredator behaviour in natural populations of the garter snake Thamnophis ordinoides[END_REF], et sa distance d'initiation en vol a montré un effet familial significatif [START_REF] King | Family, sex and testosterone effects on garter snake behaviour[END_REF]. Le comportement antipré dateur des martinets alpins adultes Apus melba é tait significativement reproductible et hé ritable sur la base des observations comportementales à long terme des parents et de la progé niture croisé e (Bize et al., 2012). Des donné es à long terme sur la FID dans une population d'hirondelles rustiques Hirundo rustica ont rapporté une hé ritabilité significative du FID avec un effet de taille de la couvé e maternelle et des hé ritabilité s similaires basé es sur la ressemblance pè reenfant et la ressemblance mè re-progé niture (Møller, 2014). Ce dernier peut suggé rer que les effets maternels ne sont pas des dé terminants majeurs de la FID chez cette espè ce. Certaines é tudes ont montré un effet du risque perç u de pré dation sur la FID des oiseaux.

La visibilité artificiellement modifié e n'a pas affecté la dé cision de vol des rosellums cramoisis Platycercus elegans lorsque leur perception globale du risque est resté e la mê me [START_REF] Boyer | Effect of visibility on time allocation and escape decisions in crimson rosellas[END_REF]. Le pluvier à double baguette Charadrius bicinctus a ré agi à la pré sence de chats et d'autres pré dateurs de mammifè res en augmentant le FID en ré ponse à l'approche Melospiza melodia é tait plus long suite à la reproduction expé rimentale des appels de pré dateurs que les vocalisations de non-pré dateurs (Zanette et al., 2011). ii Trois variables potentielles pré disant la variation interspé cifique dans le FID a masse corporelle La performance au dé collage diminue avec l'augmentation de la masse corporelle (Metcalfe et Ure, 1995, Warrick et Dial, 1998). Un organisme volant relativement grand prend plus de temps avant le dé collage, car avec l'augmentation de la taille du corps, les besoins en puissance du vol augmentent plus vite que la capacité du muscle à fournir de l'é nergie (Tobalske & Dial, 2000). Outre la relation directe entre la masse corporelle et la performance ©2010 Steve Oakes, AEBS Limited en vol, la masse corporelle est é galement le meilleur pré dicteur de l'histoire de la vie, du comportement, de la physiologie et du risque d'extinction [START_REF] Bennett | Evolutionary ecology of birds: Life histories, mating systems, and extinction[END_REF]. Il y a des raisons de croire que la FID et la masse corporelle sont significativement associé es. Les scientifiques ont remarqué que les oiseaux plus petits é taient plus accessibles que les espè ces plus grosses [START_REF] Hemmingsen | The relation of shyness (flushing distance) to body size[END_REF][START_REF] Cooke | Observations on how close certain passerine species will tolerate an approaching human in rural and suburban areas[END_REF]. L'un des meilleurs pré dicteurs de la ré ponse des oiseaux aux perturbations humaines est la masse corporelle (Samia et al., 2015b).

De nombreuses é tudes ont rapporté des corré lations positives constantes entre la FID et la masse corporelle. Blumstein (2006) chez les oiseaux a rapporté la deuxiè me plus grande taille de l'effet (0,39) de la masse corporelle (aprè s l'urbanisation) parmi les diffé rentes caté gories de traits phé notypiques (Møller, 2015). Ainsi, les grandes espè ces ont un FID relativement long (figure 5). par la thé orie de la dynamique de vol [START_REF] Rayner | Form and function in avian flight[END_REF]. Les oiseaux migrateurs ont montré une vitesse de fuite ré duite avec l'augmentation de la charge alaire (masse / aile) [START_REF] Burns | The effects of wing loading and gender on the escape flights of least sandpipers (Calidris minutilla) and western sandpipers (Calidris mauri)[END_REF]. La morphologie de la forme des ailes et de la morphologie des membres posté rieurs influence é galement la variation interspé cifique des taux de pré dation chez les passereaux [START_REF] Swaddle | Morphological adaptations to predation risk in passerines[END_REF] (Cooper & Blumstein, 2014). Ils prennent la dé cision d'é vasion la moins chè re aprè s l'é valuation et la surveillance de la menace de pré dation, ré duisant ainsi les coûts é nergé tiques du vol (Samia et al., 2015b). La taille relative du cerveau a é galement influenc é indirectement l'invasion des habitats urbains par son effet positif sur la variabilité interindividuelle de la FID (Carrete et Tella, 2011). ii Urbanisation

Les scientifiques ont remarqué que les espè ces urbaines ont gé né ralement une FID relativement courte par rapport à leurs homologues ruraux (Figure 7, [START_REF] Cooke | Observations on how close certain passerine species will tolerate an approaching human in rural and suburban areas[END_REF][START_REF] Sol | Behavioural adjustments for a life in the city[END_REF], Møller, 2015, Samia et al., 2017). L'ampleur de la diffé rence est directement lié e au temps é coulé depuis l'urbanisation (Møller, 2008a). La variation de la FID relative

(contrôlé e par la masse corporelle) des populations urbaines est positivement lié e à la densité de la population urbaine des diffé rentes espè ces [START_REF] Lin | Does avian flight initiation distance indicate tolerance towards urban disturbance?[END_REF]. L'ampleur de la variance pourrait é galement ê tre pré dite par le nombre de gé né rations depuis l'urbanisation (Møller, 2008a), comme pré vu par une sé lection progressive de la vie urbaine. Six composantes diffé rentes du comportement d'é vasion é taient lié es à l'urbanisation, suggé rant que le comportement anti-pré dateur a divergé entre les populations rurales ancestrales et les populations urbaines ré cemment é tablies [START_REF] Møller | Escape behaviour of birds provides evidence of predation being involved in urbanization[END_REF]. Ainsi, la diffé rence de FID entre les habitats ruraux et urbains est probablement lié e aux changements ré cents dans la communauté des pré dateurs suite à l'urbanisation. En effet, cette diffé rence de FID est parallè le aux tendances de l'abondance des rapaces, car elle diminue avec l'augmentation de la latitude (Dí az et al., 2013). Outre les diffé rences dans la communauté des pré dateurs, d'autres impacts potentiels de l'urbanisation qui augmentent l'é tat corporel des individus [START_REF] Geue | Reduced parasite infestation in urban Eurasian blackbirds (Turdus merula): A factor favoring urbanization[END_REF][START_REF] Delgado-V | Parasite-bird interactions in urban areas: Current evidence and emerging questions[END_REF], la disponibilité et la fiabilité des aliments [START_REF] Jokimä Ki | Biogeographical comparison of winter bird assemblages in urban environments in Finland[END_REF][START_REF] Galbraith | Supplementary feeding restructures urban bird communities[END_REF] ré duisent é galement le coût relatif du vol. Par exemple, la pré sence de mangeoires dans les habitats urbains a é galement contribué de maniè re indé pendante à une ré duction de la FID, comme le montre une é tude des populations hivernales en Pologne et des diffé rences de pré dateurs entre milieux urbains et ruraux [START_REF] Møller | Urban habitats and feeders both contribute to flight initiation distance reduction in birds[END_REF].

Cependant, toutes les espè ces ne sont pas é galement adapté es à l'urbanisation (McKinney, 2002, 2006, Morelli et al., 2016) refuge sûr pour les proies, car les pré dateurs montrent une plus grande peur de la proximité des humains que leurs proies (Møller, 2012). La moyenne spé cifique à l'espè ce et la variance de la FID conduisent à des tendances distinctes de la population pour diffé rentes espè ces et contribuent à l'homogé né isation biotique en milieu urbain. par une ré duction du rendement reproductif ou de la survie à long terme (Lima, 1998). Outre le coût é nergé tique du vol, le coût attentionnel de la surveillance des pré dateurs pour é valuer le risque de pré dation né cessite é galement une consommation d'é nergie, ce qui explique pourquoi la FID augmente (AD) ou sa distance de dé part (SD) augmente (Cooper & Blumstein, 2014). ). Les effets non lé taux du FID, associé s à la consommation directe de t = 12.46*** r = 0.79 pré dateurs et à d'autres effets non lé taux qui ré duisent ou limitent l'apport é nergé tique, peuvent tous ré duire la densité de la population [START_REF] Abrams | Foraging time optimization and interactions in food webs[END_REF].

En tant que mesure quantitative de la tolé rance des oiseaux aux perturbations, la variance de la FID devrait pré dire la diversité des ré ponses comportementales à l'environnement. Les espè ces pré sentant une plus grande diversité de comportements d'é vasion exploitent des habitats plus diffé rents en s'adaptant avec succè s à diffé rentes conditions environnementales impré visibles. Compte tenu de la forte homogé né ité individuelle du FID, la ré partition des individus entre les habitats dé pend en grande partie de leur susceptibilité aux perturbations humaines, comme le montrent les chouettes des terriers Athene cunicularia (Carrete et Tella, 2010). Des preuves provenant de 133 espè ces d'oiseaux en Europe soutiennent que les espè ces avec une plus grande variance dans le FID exploitent une plus grande diversité d'habitats que celles avec une variance relativement plus faible (Møller & Garamszegi, 2012). La variation de la variance de la volaille dans la FID é tait significative pour la diversité des habitats des espè ces (Garamszegi & Møller, 2017). Le choix du microhabitat et l'exposition post-chant du moucherolle à collier mâ le Ficedula albicollis au cours de la signalisation sexuelle sont é troitement lié s à la FID, selon le tempé rament individuel intrinsè que [START_REF] Garamszegi | Birds reveal their personality when singing[END_REF]. L'effet de la variance de la FID sur la sé lection de l'habitat peut é galement se reflé ter dans les diffé rences d'invasions de l'habitat urbain, comme mentionné dans la section pré cé dente.

VI Consé quences pour la conservation et la gestion

Manuscrit n ° 2 p. 65-71 (distances de fuite anti-pré dateur des oiseaux communs et menacé s)

Les humains influencent largement d'autres cré atures vivant sur la planè te et, par consé quent, nous subissons peut-ê tre une perte de diversité biologique [START_REF] Mcneely | The sinking ark: pollution and the worldwide loss of biodiversity[END_REF][START_REF] André N | Effects of habitat fragmentation on birds and mammals in landscapes with different proportions of suitable habitat: A review[END_REF], Vitousek et al., 1997[START_REF] Parmesan | A globally coherent fingerprint of climate change impacts across natural systems[END_REF]. Étonnamment, la perturbation due à l'activité humaine a é té le principal facteur de richesse, supplantant mê me la perte et la fragmentation de l'habitat dans une é tude de sé lection sur des communauté s d'oiseaux terrestres dans un environnement urbanisé [START_REF] Schlesinger | Distinguishing stressors acting on land bird communities in an urbanizing environment[END_REF]. Ceci est plausible parce que les stimuli d'origine humaine pourraient ê tre considé ré s comme une forme de risque de pré dation, compte tenu de sa similitude avec le risque de pré dation. Il affecte indirectement les composantes de la condition physique et la dynamique de la population par l'é nergie et les coûts d'opportunité perdus de l'é vitement des risques (Frid et Dill, 2002). Bien que les populations perturbé es soient plus tolé rantes aux perturbations humaines que les populations moins perturbé es (Samia et al., 2015b), une situation problé matique apparaî t lorsque les humains sont considé ré s comme des pré dateurs potentiels, et une tolé rance croissante aux proies pourrait accroî tre leur vulné rabilité aux pré dateurs [START_REF] Geffroy | How nature-based tourism might increase prey vulnerability to predators[END_REF]. Avec l'expansion continue de l'impact humain, la protection des espè ces sauvages devient de plus en plus importante. Le comportement d'é vasion fournit des moyens importants pour ré soudre les problè mes de conservation dans la recherche de moyens de conservation plus efficaces.

De nos jours, l'application la plus courante de FID sur la conservation est de dé finir la «distance tampon» ou les «zones tampons» (par exemple [START_REF] Rodgers | Set-back distances to protect nesting bird colonies from human disturbance in Florida[END_REF][START_REF] Rodgers | Buffer-zone distances to protect foraging and loafing waterbirds from disturbance by personal watercraft and outboard-powered boats[END_REF]. De mê me, le FID est é galement utilisé comme ré fé rence pour l'amé nagement paysager dans les ré serves naturelles ou les parcs (Ferná ndez-Juricic et al., 2001a, b, Blackwell et al., 2009)

Points de vue

Au moins trois mé canismes ont é té proposé s pour tenir compte des diffé rences de FID entre les populations d'animaux vivant dans les habitats urbains et ruraux [START_REF] Møller | Urban habitats and feeders both contribute to flight initiation distance reduction in birds[END_REF], Samia et al., 2015b, Miranda, 2017). Premiè rement, la tolé rance accrue pourrait ré sulter de Le comportement d'é vasion est souvent fortement inté gré avec d'autres aspects de la biologie d'un organisme, par ex. straté gies d'accouplement et de reproduction (Møller, 2014), systè mes gé né tiques [START_REF] Storfer | Gene flow and ineffective antipredator behavior in a streambreeding salamander[END_REF] et morphologie [START_REF] Losos | The effect of body armature on escape behaviour in cordylid lizards[END_REF]. Ces Abstract: Prey rely on escape decisions when confronted with predators to maximize the benefits of staying put while reducing the costs of predation. This life history compromise can be reflected by flight initiation distance (FID), the distance at which an individual takes flight when approached by a human. I addressed potential factors explaining variation FID with data from bird species in Europe. Genetic variability was related to predation risk FID; threatened bird species generally had a longer FID than non-threatened closely related species; evolutionary distinctiveness (ED), an indicator reflecting the phylogenetic isolation of taxa, was positively related to FID in waterbirds; mean FID of different species of birds was positively correlated with species-specific levels of MDA (malondialdehyde which is an index of oxidative stress) and UA (uric acid, which is a metric of antioxidant capacity) and FID increased with flock size in gregarious species but not in non-gregarious species. These findings may contribute to the understanding of the causes and consequences of interspecific differences in anti-predator escape behavior of birds, and, more importantly they may provide means for resolving conservation problems.

"

  Où est mon chemin de retour, Où est mon chemin de retour, Je fais fuir les aigrettes along." LI Qingzhao (dynastie Song, 1099, Chine), "Une chanson de rêve" "Where is my way home, Where is my way home, I scare away a flock of egrets." LI Qingzhao (Song dynasty, 1099, China), behavior interfere with genetic variance? II Could FID perform as an indicator of threat status of species? III Could FID contribute to long-term trait evolutionary distinctiveness? IV Is there any "side-effect" of early escape? V Does social behavior affect escape behavior? Summary I Escape from predators and genetic variance in birds II Anti-predator escape distances of common and threatened birds III Evolutionary distinctiveness covaries with anti-predator behavior in bird communities IV Flight initiation distance is correlated with oxidative stress in birds V Contagious fear: Flight initiation distance increases with flock size in gregarious birds I Anti-predator strategy and escape behavior Animals assess the surrounding environment including the threat status posed by this environment and make decisions about responses to such information by behavioral means.

Fig. 1 .

 1 Fig. 1. Optimal escape model. F0 is fitness at the out set of the encounter; B is benefit during the encounter shown as a linear function rising from zero when the prey detects the predator at distance dd to B * (the maximum benefit obtainable by not fleeing); the cost of escape is omitted from the graph (including energy expended while not engaging in fitness-enhancing activities and during escape) and Psurvival(d) = 1-e(-kd) , 0 ≤ d ≤ dd, is the probability of survival.

Fig. 2 .

 2 Fig. 2. Schematic illustration of several escape-behavior related distances and flight initiation distance calculation.

  at which an individual animal takes flight when approached by a human. The encounter is interrupted at this time and distance fled (DF) records what happens afterwards. SD is Distance

Fig. 3 .

 3 Fig. 3. Photo showing a similar situation as how FID was collected. The approaching person would stop when the target individual flew or walked away and then record the distance in meters.

Fig. 4 .

 4 Fig. 4. Vulnerability to predation by the sparrowhawk in relation to flight initiation distance (m) by different species of birds. Prey susceptibility is calculated as the observed log10transformed number of prey minus the log10-transformed expected number of prey. The line is the linear regression line. Modified from Møller et al. (2008).

Fig. 5 .

 5 Fig. 5. Flight initiation distance in relation to body mass and sexual dichromatism. The two lines are the linear regression lines for sexually monochromatic (blue points and blue line) and sexually dichromatic species (orange points and orange line). The grey areas are the 95% confidence intervals for each linear regressions. Modified from Møller et al. (2016).

c

  Cognitive ability and brain size Information on potential predation risk is collected by the sense organs and subsequently processed by the brain. Cognitive ability biases animal behavior and influences how animals

Fig. 6

 6 Fig.6 Flight initiation distance (m) in relation to wing area (m 2 ) in 63 different species of birds. The x-and y-axis are logarithmic scaled. The fit is the linear regression line. Modified from Møller et al. (2013b).

Fig. 7 .

 7 Fig. 7. Rural-urban differences in FID for 92 bird populations studied in Europe. Box-plots show median, quartiles, 5-and 95-percentiles and extreme values. Each population's trajectory is illustrated with a gray dashed line. t-values and effect sizes calculated as partial correlation coefficients are shown. The t-values was highly significant (***P < 0.001).

Fig. 8

 8 Fig. 8 Log10-transformed flight initiation distance (FID (m)) decreased with increasing band sharing coefficient across 52 species of birds. Symbol sizes are proportional to square-root transformed sample sizes. The colors represent different species with more closely related species having more similar colors. The line is the linear regression line.

Fig. 9

 9 Fig. 9 Evolutionary distinctiveness (ED) increased with increasing relative flight initiation distance (FID (m)) across 78 species of European waterbirds. Each point represents one species. Symbol sizes are proportional to square-root transformed sample sizes. The line is the linear regression line.

Fig 10 .

 10 Fig 10. Linear regression lines between flight initiation distance (FID, m) and flock size in gregarious bird species from rural and urban environments in eight European countries.

  , R.D., Pitcher, B.J. & Gardner, J.L. (2007) A mutual understanding? Interspecific responses by birds to each other's aerial alarm calls. Behavioral Ecology, 18, 944-951. Martí n, J., de Neve, L., Polo, V., Fargallo, J.A. & Soler, M. (2006) Health-dependent vulnerability to predation affects escape responses of unguarded chinstrap penguin chicks. Behavioral Ecology and Sociobiology, 60, 778-784. McGiffin, A., Lill, A., Beckman, J. & Johnstone, C.P. (2013) Tolerance of human approaches by Common Mynas along an urban-rural gradient. Emu, 113, 154-160. McKinney, M.L. (2002) Urbanization, biodiversity, and conservation: The impacts of urbanization on native species are poorly studied, but educating a highly urbanized human population about these impacts can greatly improve species conservation in all ecosystems. BioScience, 52, 883-890. McKinney, M.L. (2006) Urbanization as a major cause of biotic homogenization. Biological Conservation, 127, 247-260. McNeely, J.A. (1992) The sinking ark: Pollution and the worldwide loss of biodiversity. Biodiversity and Conservation, 1, 2-18. Metcalfe, N.B. & Ure, S.E. (1995) Diurnal variation in flight performance and hence potential predation risk in small birds. Proceedings of the Royal Society B: Biological Sciences, 261, 395-400. Miranda, A.C. (2017) Mechanisms of behavioural change in urban animals: The role of microevolution and phenotypic plasticity. Ecology and conservation of birds in urban environments (Murgui, E. & Hedblom, M.eds. ), pp. 113-132. Springer International Publishing, Cham, Switzerland. Miranda, A.C., Schielzeth, H., Sonntag, T. & Partecke, J. (2013) Urbanization and its effects on personality traits: A result of microevolution or phenotypic plasticity? Global Change Biology, 19, 2634-2644. Møller, A.P. (1988) False alarm calls as a means of resource usurpation in the great tit Parus major. Ethology, 79, 25-30. Møller, A.P. (2008a) Flight distance of urban birds, predation, and selection for urban life. Behavioral Ecology and Sociobiology, 63, 63-75. Møller, A.P. (2008b) Flight distance and blood parasites in birds. Behavioral Ecology, 19, 1305-1313. Møller, A.P. (2008c) Flight distance and population trends in European breeding birds. chickadees encode information about predator size. Science, 308, 1934-1937. Thaxter, C.B., Joys, A.C., Gregory, R.D., Baillie, S.R. & Noble, D.G. (2010) Hypotheses to explain patterns of population change among breeding bird species in England. Biological Conservation, 143, 2006-2019. Thiel, D., Mé noni, E., Brenot, J.-F. & Jenni, L. (2007) Effects of recreation and hunting on flushing distance of Capercaillie. Journal of Wildlife Management, 71, 1784-1792. Tobalske, B.W. & Dial, K.P. (2000) Effects of body size on take-off flight performance in the Phasianidae (Aves). Journal of Experimental Biology, 203, 3319-3332. Treisman, M. (1975) Predation and the evolution of gregariousness. I. Models for concealment and evasion. Animal Behaviour, 23, 779-800. Vitousek, P.M., Mooney, H.A., Lubchenco, J. & Melillo, J.M. (1997) Human domination of Earth's ecosystems. Science, 277, 494-499. Warrick, D. & Dial, K.P. (1998) Kinematic, aerodynamic and anatomical mechanisms in the slow, maneuvering flight of pigeons. Journal of Experimental Biology, 201, 655-672. Weston, M.A., McLeod, E.M., Blumstein, D.T. & Guay, P.-J. (2012) A review of flightinitiation distances and their application to managing disturbance to Australian birds. Emu, 112, 269-286. Wilson, D.S. (1998) Adaptive individual differences within single populations. Philosophical Transactions of the Royal Society B: Biological Sciences, 353, 199-205. Ydenberg, R.C. & Dill, L.M. (1986) The economics of fleeing from predators. Advances in the Study of Behavior, 16, 229-249. Zanette, L.Y., White, A.F., Allen, M.C. & Clinchy, M. (2011) Perceived predation risk reduces the number of offspring songbirds produce per year. Science, 334, 1398-1401. Zuberogoitia, I., Zabala, J., Martí nez, J.E., Gonzá lez-Oreja, J.A. & López-López, P. (2014) Effective conservation measures to mitigate the impact of human disturbances on the endangered Egyptian vulture. Animal Conservation, 17, 410-418.

Fig. 1

 1 Figure legends:

Fig. 2

 2 Fig. 2 MDA (a) and UA concentration (b) increased with increasing log10-transformed

Fig. 3

 3 Fig. 3 Phylogenetic path models averaged over all tested models for (a) concentrations of

  Fig. 1

Figure legends Figure 1 .

 legends1 Figure legends

Figure 2 .

 2 Figure 2. Linear regression lines between flight initiation distance (FID, m) and logtransformed body mass (g) in all birds recorded in this study, belonging to different trophic guilds in eight European countries. Colors indicate the diet (ESM, TableS2). Envelopes

Figure 3 .

 3 Figure 3. Linear regression lines between flight initiation distance (FID, m) and flock size in non-gregarious bird species from rural and urban environments in eight European countries species. Colors indicate bird family, and circle size is proportional to body mass of birds (g). Envelopes around lines are 95% confidence intervals.

Figure 4 .

 4 Figure 4. Linear regression lines between flight initiation distance (FID, m) and flock size in gregarious bird species from rural and urban environments in eight European countries.

  Fig. 1

ivFig. 1 .

 1 Fig. 1. Modè le d'é chappement optimal. F0 est la forme physique à l'exté rieur de la rencontre; B est bé né fique lors de la rencontre repré senté e par une fonction liné aire passant de zé ro lorsque la proie dé tecte le pré dateur à la distance dd à B * (le bé né fice maximum pouvant ê tre obtenu en ne fuyant pas); le coût d'évasion est omis du graphique (y compris l'énergie d épensée sans s'engager dans des activités d'amélioration de la forme physique et pendant l' évasion) et Psurvival (d) = 1-e (-kd), 0 ≤ d ≤ dd, est la probabilité de survie . La forme physique attendue (valeur reproductive ré siduelle) dé passe la forme initiale lorsque les

Fig. 2 .

 2 Fig. 2. Repré sentation sché matique de plusieurs distances lié es au comportement d'é chappement et du calcul de la distance d'amorç age du vol.

Fig. 3 .FID

 3 Fig. 3. Photo montrant une situation similaire à celle du FID. La personne qui s'approchait s'arrê tait lorsque la personne ciblé e volait ou s'é loignait, puis enregistrait la distance en mè tres.

i

  Risque de pré dation et FID Le risque de pré dation est susceptible d'avoir une relation concave à la hausse avec la distance par rapport aux pré dateurs potentiels, et il augmente fortement à de courtes distances (figure1,[START_REF] Cooper | Optimal flight initiation distance[END_REF]. Cette hypothè se inhé rente à la prise de risque et au FID a é té confirmé e par des preuves empiriques basé es sur des diffé rences intra et inter-espè ces. Une é tude portant sur 30 agames agama planiceps mâ les de Namibie a ré vé lé que les mâ les audacieux ayant une FID relativement courte subissaient des niveaux plus é levé s de perte de queue, probablement en raison de la pré dation[START_REF] Carter | Agamas exhibit behavioral syndromes: Bolder males bask and feed more but may suffer higher predation[END_REF]. Møller (2014) a analysé des donné es à long terme sur le FID dans une population d'hirondelles rustiques Hirundo rustica au cours de la pé riode 1984-2013 avec 2196 enregistrements pour 1789 individus. Parmi ces oiseaux, un total de 13 adultes tué s par des chats Felis catus domesticus et 5 adultes chassé s par des é perviers ont é té identifié s à partir des restes, y compris des bagues. Ces 18 individus qui sont morts de la pré dation avaient significativement moins de FID que les survivants. Des preuves plus indirectes d'espè ces d'oiseaux tropicaux jumelé s et d'espè ces d'oiseaux tempé ré s proches ont montré que les espè ces tropicales avaient une FID relativement plus courte, comme le pré dit la grande diffé rence d'abondance ou de diversité de la communauté de pré dateurs par rapport à la latitude[START_REF] Møller | Tropical birds take small risks[END_REF].La diffé rence entre les espè ces dans le FID moyen reflè te é galement la diffé rence de risque de pré dation entre les espè ces. Par exemple, dans une analyse comparative de 40 espè ces d'oiseaux, les espè ces particuliè rement sensibles à la pré dation par les é perviers ont pris leur envol à des distances plus courtes (figure4,Møller et al., 2008). Le risque de pré dation par les chats domestiques(Møller et al., 2010) et le risque de collision avec les vé hicules(Møller et al., 2011) é taient é galement né gativement lié s au FID parmi les espè ces, et ces relations restaient robustes mê me aprè s contrôle des les facteurs associé s au risque de pré dation tels que la masse corporelle et le dichromatisme sexuel. Ainsi, des FID plus longs sont associé s à un risque ré el de pré dation plus faible et à des niveaux plus faibles de prise de risque en pré sence d'un vé ritable pré dateur.

Fig. 4 .

 4 Fig. 4. Vulné rabilité à la pré dation par l'é pervier par rapport à la distance d'initiation en vol (m) par diffé rentes espè ces d'oiseaux. La susceptibilité aux proies est calculé e comme é tant le nombre de proies transformé es log10 observé es moins le nombre attendu de proies transformé es log10. La ligne est la ligne de ré gression liné aire. Modifié à partir de Møller et al. (2008).

  a rapporté une taille d'effet en termes de coefficient de corré lation produit-moment de Pearson de 0,044 pour 150 espè ces d'oiseaux. Ferná ndez-Juricic et al. (2006) ont analysé spé cifiquement la masse corporelle et la FID de 83 espè ces de 29 familles et trouvé une taille d'effet de 0,585, tandis que Weston et al. (2012) ont rapporté des FID et des informations sur la masse corporelle de 250 oiseaux australiens et ont trouvé une taille d'effet de 0,48. Møller (2008a) a é tudié des populations urbaines de 40 espè ces d'oiseaux et signalé une taille d'effet de 0,78. Une mé ta-analyse portant sur le DIF

Fig. 5 .

 5 Fig. 5. Distance d'initiation du vol par rapport à la masse corporelle et au dichromatisme sexuel. Les deux droites sont les droites de ré gression liné aire pour les espè ces sexuellement monochromatiques (points bleus et ligne bleue) et sexuellement dichromatiques (points

Fig. 6 .

 6 Fig.6. Distance d'initiation de vol (m) par rapport à la surface de l'aile (m2) dans 63 espè ces diffé rentes d'oiseaux. Les axes x et y sont mis à l'é chelle logarithmique. L'ajustement est la ligne de ré gression liné aire. Modifié à partir de Møller et al. (2013b).

  . Par exemple, la pré sence omnipré sente des humains et les perturbations constantes des vé hicules pourraient empê cher la plupart des espè ces d'envahir avec succè s les villes. Une é tude mené e en Europe a montré que les espè ces qui ré ussissent à coloniser les zones urbaines pré sentaient des é carts plus importants dans les FID de leurs populations rurales que les colonisateurs non ré ussis[START_REF] Møller | Interspecific variation in fear responses predicts urbanization in birds[END_REF]. Ceci conforte l'hypothè se que l'urbanisation ré sulte d'une colonisation diffé rentielle des zones urbaines par des espè ces aux niveaux de peur hé té rogè nes dans les populations rurales ancestrales. Une é tude sur 42 espè ces d'oiseaux dans une ville sud-amé ricaine ré cemment é tablie a é galement montré que la variabilité interindividuelle dans la peur des humains é tait positivement lié e à l'invasion urbaine contemporaine des oiseaux, positivement augmenté e par la taille relative du cerveau des espè ces(Carrete & Tella, 2011). Ainsi, le FID peut jouer un rôle crucial dans l'urbanisation des oiseaux et des espè ces avec une variance relativement importante du comportement d'é vasion, au lieu que les animaux domestiques soient mieux adapté s à l'environnement urbain. En outre, les environnements urbains sont susceptibles de cré er un

Fig. 7 .

 7 Fig. 7. Diffé rences entre les zones rurales et les zones urbaines en matiè re de FID pour 92 populations d'oiseaux é tudié es en Europe. Les boî tes à moustaches montrent la mé diane, les quartiles, les percentiles 5 et 95 et les valeurs extrê mes. La trajectoire de chaque population est illustré e par une ligne pointillé e grise. Les valeurs t et les tailles d'effet calculé es comme des coefficients de corré lation partiels sont montré es. Les valeurs t é taient hautement significatives (*** P <0,001). Modifié à partir de Samia et al. (2017).

  afin de ré duire les impacts humains sur la faune. Certaines de ces é tudes ont porté sur des espè ces menacé es (par exemple[START_REF] Gonzá Lez | Effect of human activities on the behaviour of breeding Spanish imperial eagles (Aquila adalberti): Management implications for the conservation of a threatened species[END_REF], Zuberogoitia et al., 2014), tandis que d'autres ont tenté d'inclure autant d'espè ces que possible pour é tablir une norme uniforme pour la conservation des espè ces locales. (2012) ont suggé ré de gé rer la perturbation des oiseaux australiens. Questions de recherche I Le comportement d'é chappement interfè re-t-il avec la variance gé né tique? Alors que les scientifiques ont trouvé une relation significative mais complexe entre la taille de la population, la tendance de la population et la FID, il existe peu de connaissances sur la relation entre la taille effective de la population et la FID. Les populations consanguines sont menacé es parce qu'elles ont peu de possibilité s de ré actions micro-é volutives aux changements environnementaux, et la fé condité et la viabilité des individus consanguins sont souvent ré duites par rapport aux individus non consanguins. Le comportement d'é vasion fournit le mé canisme comportemental sous-jacent qui explique la ré action des individus à des conditions environnementales dé favorables. Je pré dis que les espè ces à FID relativement longues sont aussi celles qui ont une grande variabilité gé né tique. Une FID courte indiquant un risque de pré dation supé rieur favorise une taille de population plus petite avec une variabilité gé né tique ou pourrait ê tre le ré sultat d'une faible variabilité gé né tique chez ces espè ces. En é tablissant une corré lation entre les distances d'é chappement des antipré dateurs et la variabilité gé né tique, nous pouvons mieux comprendre les mé canismes 143 responsables de la ré duction de la taille de la population, mais aussi adopter un meilleur choix de projets de ré tablissement compte tenu du grand nombre de pré dateurs dans la nature. II Le FID pourrait-il servir d'indicateur du statut de menace des espè ces? L'é tat de menace des espè ces est é valué en fonction de l'é tendue de leur habitat, de la taille de la population, du dé veloppement de la population au cours des derniè res anné es et de nombreux autres facteurs. Pendant ce temps, la distance d'initiation de vol reflè te le compromis de cycle de vie entre le risque de pré dation et les avantages de la recherche de nourriture à court et à long terme. Les espè ces ayant une FID relativement courte sont mieux à mê me de faire face à la proximité des humains et peuvent avoir plus de temps et d'opportunité s pour obtenir de la nourriture et des perspectives de reproduction et de survie supé rieures dans l'environnement avec une interfé rence humaine é levé e. Ainsi, le FID peut ê tre un pré dicteur pratique de l'é tat de menace de diffé rentes espè ces. Je m'attends à ce que les espè ces relativement menacé es aient une FID plus longue que les espè ces é troitement apparenté es, é tant donné le taux croissant de perturbation humaine et les normes d'é tat de menace. J'ai vé rifié la relation entre la FID moyenne des espè ces et le statut de la menace chez les espè ces é troitement apparenté es. III Le FID pourrait-il contribuer au caractè re distinctif é volutif du trait à long terme? La coé volution pré dateur-proie peut entraî ner une divergence rapide à la fois des pré dateurs et des proies et un comportement de fuite, car la derniè re ligne d'é vasion des pré dateurs devrait jouer un rôle crucial dans la survie des individus. Le caractè re distinctif de l'é volution (ED) reflè te l'isolement phylogé né tique des taxons avec des valeurs é levé es caracté risant les espè ces avec des phé notypes uniques qui dé vient le plus des autres taxons. Alors que la plus grande pré occupation en matiè re de conservation concerne les espè ces les plus distinctes du point de vue de l'é volution mondiale, le caractè re distinctif phylogé né tique global des zones urbaines diminue à travers le monde. Des dé cisions d'é vasion approprié es devraient é quilibrer les coûts de la perte de nourriture ou des possibilité s d'accouplement, et les avantages de s'é chapper du risque de pré dation ré duit. Un tel comportement anti-pré dateur devrait affecter la capacité à é viter la pré dation et devrait donc contribuer à des valeurs é levé es de DE chez certaines espè ces. Je m'attends à ce que la dysfonction é rectile soit d'oiseaux. Pour modé liser la relation, j'ai utilisé des modè les de ré gression phylogéné tique des moindres carré s gé né ralisé s (PGLS), suivis d'une analyse de trajectoire phylogé né tique pour examiner les relations causales potentielles entre plusieurs caractè res. La principale conclusion de cette é tude é tait que la FID moyenne de diffé rentes espè ces d'oiseaux é tait positivement corré lé e avec les niveaux de MDA et d'UA spé cifiques à l'espè ce et mé dié e par leur relation avec la masse corporelle. Ce ré sultat é tait robuste aux diffé rences dans la taille de l'é chantillon et la similitude en raison de la descendance phylogé né tique commune. V Peur contagieuse: La distance d'initiation du vol augmente avec la taille du troupeau chez les oiseaux gré gaires Au total, 7 768 observations de 35 espè ces d'oiseaux provenant de huit pays europé ens diffé rents ont é té recueillies. Diffé rentes espè ces ont é té classé es en fonction de trois variables é cologiques: la guilde trophique, la masse corporelle et la gré garité . Deux sé ries de modè les ont é té exé cuté es: Premiè rement, contrôler le signal phylogé né tique entre espè ces et ensuite les modè les non phylogé né tiques en utilisant la taille du troupeau comme facteur fixe et d'autres variables comme facteurs alé atoires. La principale conclusion de cette é tude é tait que les oiseaux sociaux ré agissaient rapidement à un pré dateur potentiel (repré senté par un FID relativement long) lorsqu'ils é taient regroupé s en grands troupeaux (figure 10), alors que ce n'é tait pas le cas chez les espè ces non gré gaires. Ces effets é taient indé pendants de la masse corporelle et de la zone gé ographique où les donné es ont é té recueillies, ainsi que du signal phylogé né tique entre les espè ces.

  l'accoutumance. Les processus de type habituel se produisent lorsque les individus sont particuliè rement sensibles aux comportements inattendus des humains et des pré dateurs potentiels, mais pas aux comportements attendus. Les changements dans la population signifient que la FID pourrait ê tre due au fait que les activité s humaines sont inoffensives et ré guliè res la plupart du temps. Deuxiè mement, la sé lection diffé rentielle parmi les syndromes comportementaux pourrait expliquer la variation du recrutement dans les 149 habitats urbains menant à un tri phé notypique sous diffé rentes pressions d'interfé rence entre les habitats urbains et ruraux. Troisiè mement, l'adaptation locale aux habitats urbains implique que les gé notypes spé cifiques ont augmenté en fré quence ou ont é té favorisé s parmi les individus urbains et devraient gé né ralement aboutir à une diffé renciation gé né tique[START_REF] Atwell | Boldness behavior and stress physiology in a novel urban environment suggest rapid correlated evolutionary adaptation[END_REF], Miranda et al., 2013). Afin de comprendre le mé canisme sous-jacent de ces diffé rences, nous avons besoin d'expé riences bien conç ues.

Fig. 10 .

 10 Fig. 10. Lignes de ré gression liné aires entre la distance d'initiation du vol (FID, m) et la taille du troupeau dans les espè ces d'oiseaux gré gaires provenant d'environnements ruraux

  corré lations suggè rent que le comportement d'é vasion peut ê tre utilisé comme un indicateur relativement facilement accessible de l'é tat gé né ral d'un organisme dans son environnement. La FID moyenne relative et la variance de la FID des espè ces devraient ê tre davantage considé ré es comme un pré dicteur des espè ces identifié es qui sont potentiellement plus vulné rables à l'augmentation des perturbations humaines plutôt que de simples mesures de la «distance tampon» . En faisant intervenir les distances d'é vacuation des antipré dateurs dans les plans de conservation et les projets de ré tablissement, il peut ê tre possible d'é valuer pourquoi certaines espè ces deviennent menacé es alors que d'autres ne le sont pas. Il pourrait aussi ê tre possible d'identifier au pré alable les espè ces pré disposé es au dé clin de la population en s'appuyant sur le FID comme outil pré dictif. Ces diffé rences de comportement peuvent fournir des moyens de ré cupé ration de ces espè ces menacé es contre les menaces causé es par la pré sence de pré dateurs, y compris les humains. Né anmoins, des expé riences bien conç ues peuvent permettre d'analyser la direction de la causalité et de mieux comprendre les FID, les syndromes comportementaux et leur signification é cologique. Université Paris-Saclay Espace Technologique / Immeuble Discovery Route de l'Orme aux Merisiers RD 128 / 91190 Saint-Aubin, France Titre: Comportement anti-pré dateur des oiseaux et conservation. Mots clé s: masse corporelle, taille du cerveau, taille effective de la population, modè le liné aire phylogé né tique, stress oxydatif, comportement social Ré sumé : Prey s'appuie sur les dé cisions d'é vasion lorsqu'il est confronté à des pré dateurs pour maximiser les avantages de rester en place tout en ré duisant les coûts de la pré dation. Ce compromis de l'histoire de vie peut ê tre reflé té par la distance d'initiation de vol (FID), la distance à laquelle un individu prend son envol lorsqu'il est approché par un humain. J'ai abordé les facteurs potentiels expliquant la variation FID avec des donné es d'espè ces d'oiseaux en Europe. La variabilité gé né tique é tait lié e au risque de pré dation FID; les espè ces d'oiseaux menacé es avaient gé né ralement une FID plus longue que les espè ces proches non menacé es; le caractè re distinctif de l'é volution (ED), un indicateur reflé tant l'isolement phylogé né tique des taxons, é tait positivement lié à la FID chez les oiseaux d'eau; La FID moyenne de diffé rentes espè ces d'oiseaux é tait positivement corré lé e avec les niveaux spé cifiques de MDA (malondialdé hyde qui est un indice de stress oxydatif) et UA (acide urique, qui est une mesure de la capacité antioxydante) et FID augmenté e avec la taille du troupeau chez les espè ces gré gaires mais pas chez les espè ces non gré gaires. Ces ré sultats peuvent contribuer à la compré hension des causes et des consé quences des diffé rences interspé cifiques dans le comportement de fuite des pré dateurs contre les pré dateurs, et, plus important encore, ils peuvent fournir des moyens de ré soudre les problè mes de conservation. Title: Anti-predator Behavior of Birds and Conservation Keywords: body mass, brain size, effective population size, phylogenetic linear model, oxidative stress, social behavior

Table 1

 1 Studies that examine different variables related to FID in birds

	Category	Variable	Reference examples
	Body	Body mass	(Holmes

Table 1

 1 Models of the relationship between log10-transformed evolutionary distinctiveness (ED) and relative FID, log10-transformed body mass (g) and log10-transformed breeding range (km 2 ), respectively, weighted by sample size for species of birds. Relative FID is the

	residual of linear regression of log10-transformed flight initiation distance (FID, m) on
	log10-transformed body mass (g) weighted by sample size for each species. (A) The linear
	model had the statistics AIC = 95.038, F4, 73 = 8.916, r 2 = 0.328, P < 0.001. (B) The
	phylogenetic generalized linear model had the statistics AIC = 38.180, F4, 73 = 3.074, r 2 =
	0.112, P < 0.001.
	Term	Estimate Standard Error d.f.	F	P
	(A)
	(Intercept)	0.080	0.759	78 (total)
	Relative FID	0.364	0.171	1	5.739	0.019
	log10-transformed body mass	-0.282	0.083	1	21.193 < 0.001
	log10-transformed range	0.198	0.099	1	2.191	0.143
	Migratory status	-0.247	0.096	1	6.542	0.013
	(B)
	(Intercept)	0.790	0.325	78 (total)
	Relative FID	0.211	3.136	1	13.398 0.001
	log10-transformed body mass	-0.297	1.517	1	22.597 < 0.001
	log10-transformed range	0.042	1.813	1	2.327	0.132
	Migratory status	0.041	1.769	1	2.497	0.118

Table 2 .

 2 Results of Generalized Linear Mixed Models (non-phylogenetic models), accounting for variation in flight initiation distance (FID) in relation to flock size and habitat (urban or rural) in non-gregarious and gregarious bird species, based on data from eight European countries. The full model is based on 2014 observations for non-gregarious and 5754 observations for gregarious birds. Random effects were entered in the models: city

	(groups = 8), quantiles for body mass (groups = 4 for non-gregarious, 5 for gregarious birds),
	diet (groups = 4) and bird species (groups = 10 for non-gregarious, 23 for gregarious).
	Abbreviations: ES, estimate; CI, 95% confidence interval (lower / upper values); SE,
	standard error; t statistic and p-value. Significant variables are highlighted in bold.
	Variables	Estimate	CI	SE	t	p
	Non-gregarious birds
	(Intercept)	17.711	11.713 / 23.709 3.060	5.787	2e-05
	Flock size	-0.015	-0.814 / 0.783	0.407	-0.038	0.969
	Habitat (urban)	-5.860	-6.699 / -5. 021 0.428	-13.679 2e-16
	Gregarious birds
	(Intercept)	15.931	11.098 / 20.763 2.465	6.426	2e-05
	Flock size	0.338	0.284 / 0.393	0.028	12.124	2e-16
	Habitat (urban)	-6.154	-6.715 / -5.593	0.286	-21.499 0.961

  . Ainsi, le DIF chez les oiseaux pourrait varier avec la morphologie des ailes et des membres posté rieurs. Par exemple, une é tude comparative sur 83 espè ces d'oiseaux a montré que les oiseaux ayant des ailes plus pointues fuyaient sur de plus longues distances et se posaient plus loin que les espè ces aux ailes arrondies (Ferná ndez-Juricic et al., 2006). De même, les espè ces ayant une FID longue pour mé tabolisme qui permet le fonctionnement normal d'un individu dans son environnement, é tait é galement positivement lié au FID (Møller, 2009). Ainsi, le comportement d'é chappement a coopé ré avec un certain nombre d'adaptations et de contraintes diffé rentes en termes de morphologie. c Capacité cognitive et taille du cerveau Les informations sur le risque de pré dation potentiel sont collecté es par les organes sensoriels et ensuite traité es par le cerveau. La capacité cognitive fausse le comportement des animaux et influence la faç on dont les animaux interagissent avec les habitats naturels[START_REF] Dukas | Cognitive ecology II[END_REF]. Un certain nombre d'é tudes ont montré que les animaux utilisent des capacité s cognitives pour accé der au comportement des pré dateurs qui se manifestent par une distance de vol modifié e. Par exemple, les oiseaux ont des FID plus courts s'ils sont approché s tangentiellement plutôt que directement[START_REF] Ferná Ndez-Juricic | Sensitivity of wildlife to spatial patterns of recreationist behavior: A critical assessment of minimum approaching distances and buffer areas for grassland birds[END_REF][START_REF] Geist | Does intruder group size and orientation affect flight initiation distance in birds?[END_REF]

	leur taille corporelle avaient é galement de grandes surfaces alaires et des rapports d'aspect
	(figure 6, Møller et al., 2013b). La relation entre la morphologie des espè ces et le DIF
	pourrait é galement ê tre expliqué e d'un point de vue physiologique puisque le FID est

né gativement relié à l'hé matocrite, une mesure du volume des globules rouges tassé s et indique ainsi la capacité de transport de l'oxygè ne et donc la ré action de contraction des muscles.

Møller et al., 2013b)

. Le taux mé tabolique de base (BMR), repré sentant le niveau minimum de al., 2005; Møller & Tryjanowski, 2014), ou s'ils sont abordé s avec des yeux humains plutôt ailleurs. que de les regarder directement (Bateman & Fleming, 2011). Dans une é tude comparative de 107 espè ces, Møller & Erritzøe (2014) ont constaté que les oiseaux ayant un cerveau relativement gros pour leur taille corporelle é vitaient la rué e vers l'approche d'un pré dateur. La corré lation né gative pourrait ê tre causé e par des espè ces avec des cerveaux relativement grands connaissant plus de coûts d'opportunité contrôlant l'intention du pré dateur (par exemple, grâ ce à une meilleure é valuation de la distance et de la vitesse du pré dateur)

Acknowledgements

I would like to thank my jury who accepted to assess my thesis and have come from afar to hear my voice: Emmanuelle Baudry, Martina Carrete, David Costantini and Raivo Mä nd.

Acknowledgments

Y. Jiang was supported by the China Scholarship Council (ref. 201406510028).

This thesis and I was supported by a cooperation between China Scholarship Council and

Université Paris-Sud (ref. 201406510028).

Flight initiation distance is correlated with oxidative stress in birds

Yiting Jiang and Anders Pape Møller

Ecologie Systé matique Evolution, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, F-91405 Orsay Cedex, France * Correspondence to YJ: Tel: (+33) 6 83 00 57 79 E-mail: yiting.jiang@u-psud.fr Running headline: Jiang and Møller: Oxidative stress, brain mass and FID Word count: 5575

Contagious fear: Flight initiation distance increases with flock size in gregarious birds

Morelli, Federico; Benedetti, Yanina; Dí az, Mario; Grim, Tomas; Ibá ñez-Álamo, Juan; Jokimaki, Jukka; Kaisanlahti-Jokimä ki, Marja-Liisa; Kä tte, Kunter; Marko, Gabor; Jiang, Yiting; Tryjanowski, Piotr; Møller, Anders

Ré sumé en franç ais

Cette partie est google traduit en fonction de la partie d'introduction. Pour mieux comprendre la thè se, veuillez lire la version anglaise.

individuals (Carrete and Tella 2011) with relatively short FID. Thus species with high ED will be under strong selection in urban environments. This is consistent with the negative impact of urban environments on the evolutionary uniqueness of birds (Morelli et al. 2016).

However, the rate of speciation decreased with clade age [START_REF] Ricklefs | Global variation in the diversification rate of passerine birds[END_REF], which may increase ED. We should pay increased attention to the protection of high-ED species since such species with consistently long FID are more likely to be threatened than their close relatives [START_REF] Jiang | Antipredator escape distances of common and threatened birds[END_REF].

In conclusion, we have demonstrated a significant positive relationship between ED and FID, even when controlling statistically for potentially confounding variables. This paper constitutes the first attempt to associate current behavior with evolutionary distinctiveness.

The results contribute to our understanding of the link between ED and life-history, and they may help us understand the evolution of species with high ED.

Supplementary Material

Further details on the data sets used (Appendix A) are available on-line.

Author contributions

Idea: Y.J. and A.P.M.; data analysis: Y.J.; data collection: A.P.M.; writing the manuscript: Y.J. and A.P.M.

Abstract

Oxidative stress is closely related to life-history and ecological traits. All animals flee from potential predators including humans thereby incurring metabolic costs. Oxidative stress arises from the production of free radicals and thereby plays a core role in the evolution of optimal investment trade-offs between reproduction and survival. Oxidative stress is the outcome of metabolism and it is produced by a number of stressful events. Predators constitute an important component of stress in the daily life of prey. Frequent flights from potential predators are energetically expensive and may reach more than 20 times basal metabolic rate, thereby contributing to the production of free radicals and hence oxidative stress. The distance between animals and potential predators when a prey individual takes flight is defined as the flight initiation distance (FID). A relatively short FID indicates comparatively frequent flights. Here we show for the first time that free-living birds with relatively short FID for their body mass experienced more peroxidative damage to lipids (malondialdehyde, MDA), and that they had an up-regulated component of antioxidant capacity (uric acid, UA). These relationships were mediated through relationships with body mass. Brain size was positively related to the level of UA but also to behavioral anti-predator responses. Therefore, we can conclude that anti-predator behavioral strategies of birds have at least partially evolved as a means of managing oxidative stress. Keywords: antioxidant defenses; birds; non-lethal effect; oxidative damage; predation. among correlated covariates. Consequently, we used body mass and brain mass in the same model to control for these confounding effects. Information on body mass was extracted from Dunning (2007). If both male and female body mass were provided, we used the average value. The entire data set is reported in supplementary information Appendix S1.

Comparative analyses

To model the relationship between FID and oxidative stress, we used phylogenetic generalized least square (PGLS) regression models (Garamszegi, 2014). PGLS models avoid the problem of statistical dependence in comparative analyses due to phylogenetic relatedness between species. PGLS models were implemented in packages ape (Paradis et al., 2004) and nlme (Pinheiro et al., 2016) and the function gls with correlation equaling the consensus tree. We log10-transformed FID, brain size and body mass to obtain variables that follow normal distributions allowing for the use of parametric statistics. We extracted the phylogenetic relationship for all 72 species from a phylogeny available online (Jetz et al., 2012) and obtained a consensus phylogeny from 1000 trees with Mesquite 3.31 (Maddison & Maddison, 2017). We separately analyzed MDA, TAS and UA in the phylogenetic analysis since the species were slightly different.

It is difficult to examine relationships between more than two traits, especially when any trait can contribute to another, or the other way around, and potential correlations can also result in indirect complex relationships between study variables. To test whether the covariances between FID and redox state markers were caused by their common association with body mass, we used phylogenetic path analysis. Path analysis is a powerful statistical method to resolve the complex natural systems in a single causal network and analyze the relative importance of alternative causal models [START_REF] Shipley | A new inferential test for path models based on directed acyclic graphs[END_REF]. Phylogenetic path analysis may help verify if the covariance could be a potential causal relationship as well as controlling for non-independence due to a common ancestor [START_REF] Gonzalez-Voyer | An introduction to phylogenetic path analysis[END_REF]. The structure of the phylogenetic path analysis was designed based on previous knowledge of the variables and also on hypotheses to be tested. For instance, oxidative stress may impose an important physiological cost on intense physical activity [START_REF] Costantini | Oxidative stress in ecology and evolution: Lessons from avian studies[END_REF]. Large-brained birds suffer less oxidative damage [START_REF] Vá Gá Si | Morphological adaptations to migration in birds[END_REF].

Relatively large brain size is associated with better cognitive ability (Møller, 2015) and potentially affects anti-predator behavior (Samia et al., 2015). The minimal set of conditional independencies for each path model was tested using PGLS models in the package caper [START_REF] Orme | The caper package: Comparative analysis of phylogenetics and evolution in R[END_REF]. Path models for the data were estimated via the C value.

A significant C statistic indicates that the model is a poor fit to the data. To compare the different path models and identify the most likely causal scenarios, we used the C-statistic Including different indicators of oxidative stress (two out of four components: free radical production, antioxidant defenses, oxidative damage and repair mechanisms) provide relatively more information [START_REF] Monaghan | Oxidative stress as a mediator of life history trade-offs: Mechanisms, measurements and interpretation[END_REF] on the relationship between FID and the levels of oxidative stress. For instance, while MDA level reflects oxidative damage among individuals of a given species, UA represents different mechanisms of antioxidant defense and TAS describes total antioxidant status of individuals of a given species.

Although brain size is positively related to MDA, and neural tissue is energetically expensive and demands antioxidants [START_REF] Isler | Metabolic costs of brain size evolution[END_REF], we did not find a direct correlation between brain size and MDA in the phylogenetic path analysis. Rather, brain size only directly increased UA level. This result partially supports the 'oxidation avoidance' hypothesis proposed by Vá gá si et al. ( 2016) that species with relatively large investment in the brain also allocate more to self-maintenance including an efficient antioxidant defense machinery.

We did not find a direct significant path correlation between brain size and FID. Brain size is identified as a major determinant of avian escape strategy (Samia et al., 2015), but that could be explained by associated cognitive functions (reviewed by [START_REF] Sol | The cognitive-buffer hypothesis for the evolution of large brains[END_REF]. For instance, larger brains help birds respond to novel conditions by enhancing their propensity to innovate rather than indirectly through non-cognitive mechanisms [START_REF] Sol | Big brains, enhanced cognition, and response of birds to novel environments[END_REF]. The decisive role of brain size could also be explained through its coevolution with relative eye size in birds in response to nocturnal activity and, at least partly, to capture of mobile prey [START_REF] Garamszegi | Coevolving avian eye size and brain size in relation to prey capture and nocturnality[END_REF]. Species with higher visual acuity are able to detect a predator model from farther away (Ferná ndez-Juricic & Kowalski, 2011), and species that flee at longer distances from an approaching potential predator have relatively large eyes for their body size (Møller & Erritzøe, 2010).

Sudden take-offs from a potential predator are costly (Tatner & Bryant, 1986), and it is associated with oxidative stress. As an important part of an individual's daily life, antipredator behavior measured as FID contributes to the level of oxidative stress. Oxidative stress from extended flights have long been neglected until recent studies found that flying birds experience oxidative stress during long distance migration [START_REF] Costantini | Oxidative damage and anti-oxidant capacity in two migratory bird species at a stop-over site[END_REF][START_REF] Costantini | Long flights and age affect oxidative status of homing pigeons (Columba livia)[END_REF]. Migrants seek to balance different options to achieve optimum strategies for coping with energy consumption during migration [START_REF] Hedenström | Optimum Fuel Loads in Migratory Birds: Distinguishing Between Time and Energy Minimization[END_REF]. They experience oxidative stress during endurance flight and increase their antioxidant capacity to cope with this stress [START_REF] Jenni-Eiermann | Oxidative stress in endurance flight: An unconsidered factor in bird migration[END_REF]. Management of oxidative stress is likely to be a major determinant of life histories [START_REF] Hulbert | Life and death: Metabolic rate, membrane composition, and life span of animals[END_REF]. Understanding the

Conflicts of interest

We declare that we have no conflicts of interest. inference was performed using the package 'AICcmodavg' in R [START_REF] Mazerolle | AICcmodavg: Model selection and multimodel inference based on (Q)AIC(c). R package[END_REF]. The best model was selected considering both lowest AICc and large Akaike weights, because this model had the strongest support for data [START_REF] Mazerolle | AICcmodavg: Model selection and multimodel inference based on (Q)AIC(c). R package[END_REF]. Model averaging was used to obtain parameter estimates for all variables entered in the models. The model averaging calculation was done on the most parsimonious models [START_REF] Grueber | Multimodel inference in ecology and evolution: Challenges and solutions[END_REF], using the package 'MuMIN' for R [START_REF] Bartoń | MuMIn: multi-model inference, R package[END_REF]. The confidence intervals for the significant variables in each model were calculated by the Wald method using the package 'MASS' [START_REF] Venables | Modern Applied Statistics with S. 4th edn[END_REF].

All statistical tests were performed with R software (R Core Team, 2017).

Results

From a total of 9,871 observations from eight different European countries (Fig. 1; ESM, Table S1) we filtered 7,768 observations of 35 bird species with sample size of FID available for more than 50 observations (ESM, Table S2).

In the initial exploration of data, FID was strongly positively correlated with body mass, in each category of trophic guild, with more pronounced slopes for insectivorous, carrioneaters and granivorous-insectivorous birds than other categories (Fig. 2).

The average FID was slightly longer in gregarious than in non-gregarious birds (12.2 m and 10.4 m, respectively; t = -6.9, df = 4307.4, p = 5.7e-12; ESM, Fig. S1). The average flock size was larger in gregarious than in non-gregarious birds (2.3 and 1.1, respectively; t = -17.6, df = 6058.5, p < 2.2e-16; ESM, Fig. S1).

When considering separately the two categories of gregariousness of bird species, flock size was not significantly related to FID for non-gregarious species (Fig. 3), while it was strongly positively correlated with the number of individuals in a flock for gregarious birds (Fig. 4), in all models (Tables 1 and2). Additionally, in the phylogenetic model, FID was negatively correlated with urban habitat for both gregarious and non-gregarious species, while it was positively correlated with body mass for both gregarious and non-gregarious birds. Latitude was negatively associated with FID for non-gregarious birds, while was only slightly positively associated to FID for gregarious birds. Finally, we found a negative association between FID and insectivorous diet for gregarious birds (Table 1).

The second modeling procedure, based on non-phylogenetic models, confirmed that the positive and significant association between FID and flock size verified for gregarious birds was valid even independently of body mass, diet or bird species considered (Table 2).

Table 1. Results of phylogenetic generalized linear regression model (PGLS), accounting

for variation in flight initiation distance (FID) in relation to flock size, habitat (urban or rural), latitude, body mass and diet in non-gregarious and gregarious bird species, based on data from eight European countries, weighted by sample size for species of birds. The model for non-gregarious birds had the statistics F7,184 = -35.931, r 2 = 0.187, P < 0.0001 and the model for gregarious birds had the statistics F7, 946 = -23.325, r 2 = 0.128, P < 0.0001. Abbreviations: SE, standard error. Significant variables are highlighted in bold. [START_REF] Bennett | Ultraviolet plumage colors predict mate preferences in starlings[END_REF][START_REF] Ballentine | Female mate choice in relation to structural plumage coloration in blue grosbeaks[END_REF][START_REF] Leitã O | Ultraviolet reflectance influences female preference for colourful males in the European serin[END_REF] et l'allocation sexuelle des descendants [START_REF] Griffith | Correlations between ultraviolet coloration, overwinter survival and offspring sex ratio in the blue tit[END_REF][START_REF] Romano | Sex allocation according to multiple sexually dimorphic traits of both parents in the barn swallow (Hirundo rustica)[END_REF].

Variables

ii Flocage

De nombreuses espè ces ont dé veloppé des agré gations sociales. Un troupeau a plus de chances de dé tecter un danger qu'un individu solitaire [START_REF] Darwin | The descent of man and selection in relation to sex[END_REF] en raison de la dé tection collective (Pulliam, 1973). La distance individuelle de dé tection d'un pré dateur augmente é galement avec la taille du troupeau, ce qui augmente la probabilité d'é vasion [START_REF] Kenward | Hawks and doves: Factors affecting success and selection in goshawk attacks on woodpigeons[END_REF]. Si un pré dateur ne prend qu'une proie individuelle ou un nombre infé rieur à la taille d'un groupe, la probabilité d'ê tre capturé serait plus faible que pour un individu solitaire d'une proie [START_REF] Hamilton | Geometry for the selfish herd[END_REF]. Cette dilution du risque, la probabilité ré duite d'ê tre capturé e dans des groupes plus importants, a é té observé e à de nombreuses reprises (par exemple, [START_REF] Munro | Gull predation and creching behaviour in the common eider[END_REF][START_REF] Cresswell | Flocking is an effective anti-predation strategy in redshanks, Tringa totanus[END_REF][START_REF] Beauchamp | Disentangling risk dilution and collective detection in the antipredator vigilance of semipalmated sandpipers in flocks[END_REF]. Les avantages de la dé tection et de la dilution s'entrecroisent à un moment donné [START_REF] Bednekoff | Re-examining safety in numbers: Interactions between risk dilution and collective detection depend upon predator targeting behaviour[END_REF]: la vigilance offre relativement moins d'avantages aux groupes plus importants, mais les deux avantages peuvent atteindre des limites et la probabilité diminue lé gè rement lorsque la taille du groupe augmente. En plus de ré duire le risque de pré dation, la collecte en groupe ré duit é galement le temps consacré à la vigilance et amé liore les possibilité s de recherche de proies individuelles [START_REF] Morse | Feeding behavior and predator avoidance in heterospecific groups[END_REF][START_REF] Ferná Ndez | Effect of group size on individual and collective vigilance in greater rheas[END_REF][START_REF] Beauchamp | Social predation: How group living benefits predators and prey[END_REF], 2015).

iii Appels d'alarme

Quand une personne-proie a dé jà dé couvert un pré dateur, sa proie peut é mettre des appels d'alarme ou percevoir des signaux d'avertissement d'autres individus. Les appels d'alarme transmettent des informations sur la menace, y compris le type de pré dateur [START_REF] Seyfarth | Vervet monkey alarm calls: Semantic communication in a free-ranging primate[END_REF], la taille d'un pré dateur (Templeton et al., 2005), le comportement d'un pré dateur [START_REF] Griesser | Referential calls signal predator behavior in a group-living bird species[END_REF], l'urgence de ré pondez [START_REF] Leavesley | Communicating about danger: Urgency alarm calling in a bird[END_REF] et beaucoup d'autres indices de la menace. Ainsi, les appels d'alarme protè gent les individus du groupe qui parasitent le comportement anti-pré dateur de l'individu qui é met l'appel d'alarme, tout en bé né ficiant à l'individu alarmé lui-mê me. Il y a des appels de fausse alarme effectué s comme un moyen d'usurpation des ressources, augmentant ainsi la propre probabilité des appelants d'accé der à la nourriture (par exemple [START_REF] Munn | Birds that "cry wolf[END_REF], Møller, 1988). La reconnaissance des signaux d'avertissement intraspé cifiques et interspé cifiques constitue positivement lié e à la FID, car les espè ces qui prennent le moins de risques lorsqu'elles rencontrent des pré dateurs sont moins sensibles à la pré dation. Le test de cette corré lation entre les caractè res ED et comportementaux en cas de sé lection forte peut nous aider à comprendre l'é volution de l'ED et donc à permettre une meilleure protection de ces espè ces.

IV Y a-t-il un «effet secondaire» d'une é vasion pré coce?

Bien que les individus qui prennent un vol rapide à l'approche des pré dateurs prennent de petits risques lors des rencontres, ils doivent é galement dé coller plus fré quemment à la mê me fré quence d'interfé rence. Un battement aé rien court et bref est mé taboliquement coûteux, ce qui peut entraî ner un taux mé tabolique basal de 23 fois (Tatner et Bryant, 1986).

Les vols d'é vasion fré quents en pré sence de pré dateurs potentiels sont é nergé tiquement

V Le comportement social affecte-t-il le comportement d'é vasion?

La sociabilité (directement lié e à la taille du groupe) a une taille d'effet moyenne intermé diaire de 0,26 sur FID dans une mé ta-analyse de facteurs coopé ratifs chez les oiseaux (Møller, 2015). La taille du groupe a é galement é té suggé ré e comme un trait de proie important qui influence les dé cisions d'é vasion (Samia et al., 2017). La dé tection collective (probabilité accrue de dé tection d'un pré dateur dans des groupes plus importants, Pulliam, 1973) et la dilution du risque (probabilité ré duite d'ê tre capturé e dans des groupes plus importants, [START_REF] Hamilton | Geometry for the selfish herd[END_REF]) pourraient affecter le comportement d'é chappement des individus. Des é tudes anté rieures avaient dé montré que le FID é tait positivement lié à la taille du troupeau (Laursen et al., 2005, Tä tte et al., 2018) 8), (2) hé té rozygotie et (3) coefficient de consanguinité é taient toutes lié es à la forte approximation du risque de pré dation ré el (FID). Ainsi, des niveaux plus é levé s de variabilité gé né tique é taient systé matiquement associé s à une FID plus longue.

Ces ré sultats é taient robustes aux effets potentiellement confondants de variables telles que l'aire de reproduction, la taille de la population et la masse corporelle.

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