Professor, Helga-Jane Scarwell
email: helga.scarwell@univ-lille.fr

Divya Leducq
email: divya.leducq@univ-tours.fr

DANANG, A SECONDARY CITY SUBJECT TO ASPIRATIONAL URBANISM

Keywords: Urban studies, Digital transformation, Circulation of urban ideas and models, Green Asian studies, Emerging economy, Spatial issues, Urban planning, Vietnamese metropolises

Provides a comprehensive overview of a secondary city in Vietnam • Analyzes how local leaders and stakeholders have brought about

Introduction

Recent urban studies about Vietnam have highlighted the fact that, behind globalization, which anchors the flow of capital around emblematic urban operations, more diffuse processes are at work. For example, the outskirts of the major cities are gradually being transformed [START_REF] Labbé | Critical reflections on land appropriation and alternative urbanization trajectories in periurban Vietnam[END_REF], and bottom-up dynamics are transforming urban districts through modernization of road networks [START_REF] Gibert | Rethinking metropolitan production from its underside: a view from the alleyways of Ho Chi Minh City[END_REF]. In addition to the major trends observed in the political and economic capitals, Hanoi and Ho Chi Minh City (HCMC), smaller cities in Vietnam, such as Danang and Haiphong, have also been affected by transformations. While these secondary centers are less privileged or are further from the powerful metropolises [START_REF] Goldblum | Cities at the Edge of Metropolization in Southeast Asia[END_REF], their dynamics of change need to be documented [START_REF] Cosaert | Introduction : Tensions du développement vietnamien[END_REF]. Based on qualitative material gathered during four months of field work in 2019 1 , this work extends the literature on the emergence, unregulated urbanization and on-going metropolization of South-East Asian cities [START_REF] Eunhee | Conceptual Planning for Danang High-Tech Park[END_REF]Leducq et Scarwell, 2018a;[START_REF] Hang | Chapter 5: Danang City Development[END_REF][START_REF] Bouchot | Le Vietnam : miroir des défis environnementaux, sanitaires et alimentaires[END_REF][START_REF] Gibert-Flûtre | Documentation photographique : L'Asie du Sud-Est[END_REF]. The article aims to bridge the current gap between urban studies on emerging cities and urban planning theory [START_REF] Balbo | Beyond the city of developing countries. The new urban order of the 'emerging city[END_REF]. Driven by metropolization, secondary cities in emerging economies are witnessing significant changes that affect their social and spatial structure [START_REF] Robinson | Global and world cities. A view off the map[END_REF].

To this end, the article analyzes changes in Danang 2 , the only urban area of demographic and functional importance in the Center region of Vietnam (fig. 1). It is the third largest urban area of the country, comprising mainly small and medium-sized towns, and it was previously considered as peripheral. But has it now become an emerging metropolis [START_REF] Goldblum | Figures de la transition urbaine en Asie du Sud-Est[END_REF]Géoconfluences, 2019)? Our aim was thus to understand the role Danang plays in Vietnamese growth, both as a magnet for investment and in wealth creation (Bony-Cisternes, 2019), while showing the limits of the current metropolitan transition [START_REF] Goldblum | Cities at the Edge of Metropolization in Southeast Asia[END_REF] and the risk of running out of steam. While a number of policy decisions have enabled Danang to move beyond its initial role of relieving 1 This article is based on statistical data obtained at the provincial level, allowing comparison with the national level and the major cities of Vietnam. It is also based on a sample of 8 interviews with urban stakeholders (at the central level in Hanoi: a deputy for the province of Danang on the People's Committee, a civil servant from the Ministry for Construction responsible for the Smart Cities program; at the local level: a development officer for Danang city-province, an architect-urban planner, a property developer) and economic development stakeholders in Danang (a company director, two founders and managers of third spaces). Finally, a portfolio of photographs showing on-going changes is compared with past and present urbanism documents. 2 Covering an area of approximately 1280 km 2 and with nearly a million inhabitants in 2019 (740 inhab/km 2 ), Danang comprises 6 urban districts (Hai Chau, Cam Le, Thanh Khe, Lien Chieu, Ngu Hanh Son and Son Tra), 1 rural district (Hoa Vang), and 1 island district (Hoang Sa) (fig. 2). congestion in Hanoi and Ho Chi Minh City [START_REF] Gironde | Vietnam : les nouveaux territoires d'une modernisation inégalitaire[END_REF], gradually enabling it to become a regional economic hub, the process has not always been smooth, and urban stakeholders have been confronted with new problems that pose a challenge for future development. This can be seen as part of a secondary metropolization process; at the national level, this is evidenced by a shift from the previous social and spatial polarization of Vietnam to a more composite contemporary model, with intermediate cities or emerging metropolises, such as Haiphong in the north, Danang in the center and Bong Duong in the south [START_REF] Tran | La construction métropolitaine au Sud du Vietnam[END_REF] being added to the metropolises of Hanoi (Northern Vietnam) and Ho Chi Minh City (Southern Vietnam). To explain the emergence of Danang, the article is divided into three sections. First, we describe the historical-political construction of urban centrality and the resources and effects of the development of tourism in Danang. This includes the geographical advantages that have enabled Danang to use its spatial resources to become a participant in globalization. Secondly, we will look at the plans and projects of public and private stakeholders involved in the process of regional metropolization based on two successive strategies: development of upmarket tourism taking a pragmatic approach, and development of the knowledge economy, based on the concept of a global smart city. We examine the locations, stakeholders and temporal frames of the concomitant urban strategies that are being used to create a "smart city" through several urban planning tools and foreign direct investment (FDI). Finally, we highlight the limits and pitfalls of the regional development choices that have been made.

State of the art

Emergence of secondary cities in Asia

In recent years, the number of metropolitan areas in Asia has increased, particularly secondary cities, coastal cities or cities linked to their deep-water ports, such as Danang. This metropolization process concerns densely populated areas, and is based as much on the economic development of the coast since the 1980s as on planning and infrastructure. This article proposes a new reading of the metropolization process of secondary cities, such as Danang, a regional capital in the Asia-Pacific region. This city is undergoing transformation on such a scale and at such a pace that it can be interpreted in terms of metropolization, in which project-based urban planning plays a predominant role. Our paper examines the processes of metropolization at the margins. We seek to determine the pace, circumstances, and scale of emergence of the extended metropolis of Danang, and the actors in this process. To study this metropolization of a second-tier city, we build on the knowledge and research of [START_REF] Goldblum | Ho Chi Minh Ville, analyseur de la métropolisation du sud-est asiatique[END_REF] and [START_REF] Franck | Territoires de l'urbain en Asie du Sud-Est. Métropolisations en mode mineur[END_REF]. These studies show that the mechanisms of internationalization of major urban hubs also concern, albeit to a lesser extent, the metropolization of secondary cities.

Based on the specific characteristics of the processes of metropolization of secondary cities [START_REF] Goldblum | Cities at the Edge of Metropolization in Southeast Asia[END_REF], we examine the specific case of Danang, which is of particular interest because of the new regional configurations and the strengthening of its maritime role that make it a key global player. Urbanization is both the vector and the modus operandi of this rise in metropolization. The internationalization of urban development, in which foreign direct investment plays an increasingly important role, has accelerated the transformation of the city and the process of metropolization.

However, the impact of foreign investment influences the form, scale and status of real estate operations to the extent that there is often a time lag between the development phase of the Master Plan, the date of its approval, and completion. Asian urbanism "can be seen as both actually existing and imagined" [START_REF] Shin | Asian Urbanism[END_REF], and is constantly in the making across time and space, either materialized or existing only in policy documents and master plans [START_REF] Watson | African Urban Fantasies: Dreams or Nightmares?[END_REF]). Danang's urban development also reflects changes in its historical and geographical circumstances and its experiences of coping with urban challenges. However, the urban aspirations underlying the Master Plan make it worthy of attention. The theoretical and empirical analysis of the urban planning of this secondary city and emerging metropolis can help conceptualize the way the future is imagined through an array of spatial practices. Relatively little attention has been paid to the way in which secondary cities engage futurity in their everyday lives and on their territory [START_REF] Bunnell | The prospects of elsewhere: engaging the future through aspirations in Asia[END_REF].

The intersection between aspirational urbanism and project-based urbanism

The process of "secondary metropolization" described above (Franck et al., 2012: 18) is based on the notion of "aspirational urbanism" [START_REF] Appadurai | The capacity to aspire: culture and the terms of recognition[END_REF][START_REF] Appadurai | The future as cultural fact: Essays on the global condition[END_REF][START_REF] Bunnell | Urban aspirations and Asian cosmopolitanisms[END_REF]. According to Appadurai, urban aspirations are an important driver of urban transformation, usually incrementally, and they are never simply individual (Appadurai, 2013: 67). In accordance with Bunnell, "a focus on aspirations thus enables us to get at the human driving force of urban change, both radical and mundane". The appropriation of individual and collective urban aspirations has been made possible in Danang through consolidated local politico-economic structures that displace both the present and the future [START_REF] Shin | Whither progressive urban futures? Critical reflections on the politics of temporality in Asia[END_REF]. Urban aspirations can be shared and negotiated by everyone -authorities, technocrats, planners, developers, political elites -and take shape according to the complexities of the context. Metropolization is understood as a dynamic and unfinished process generated by internationalization and the input of foreign direct investment (FDI). To further Danang's urban development, a new configuration of urban planning stakeholders has been formed through a network of domestic and overseas companies as well as governmental players (e.g., state-owned enterprises, government-linked companies), working closely together "to turn aspirational Asian urbanism into actionable plans" [START_REF] Shin | Asian Urbanism[END_REF] through project-based urbanism. This paper seeks to reveal not only neglected dimensions of the urban transformation of secondary cities such as Danang, but also opens up new theoretical perspectives of the multi-faceted experience of urban futurity. Several driving forces play a fundamental role in the metropolization of a secondary city like Danang. Historically, the exclusive economic zone constituted the "backbone" of this dynamism. Today, Danang Municipal Authority focuses on tourism, new trans-provincial roads, transnational development corridors and the international port. Finally, real estate development has become the driving force behind the production of residential stock and the reconfiguration of regional infrastructures. Are we witnessing a new stage in the process of metropolization of this secondary city, differing in nature and intensity from the processes involved in major urban centers? Until recently, this project-based urban development was mainly financed by the Vietnamese State, which wished to reinforce the country's southern structure by providing the Central region with a real economic capital.

In order to finance this aspirational urbanism and the urban development projects, there has now been a shift towards the "privatization of planning" [START_REF] Shatkin | City and the bottom line: urban megaprojects and the privatization of planning in Southeast Asia[END_REF], and the production of vertical forms of urban development, especially in the coastal area [START_REF] Shin | Vertical Accumulation and Accelerated Urbanism: The East Asian Experience[END_REF]. This vertical urbanism is linked to "processes of speculative urbanism" (op. cit.).

Metropolitan emergence of secondary cities: the case of Danang within Vietnam

Historical and political construction of a new urban centrality

Danang is a coastal city on the north-south axis of Vietnam's road, rail, sea and air transport systems (fig. 2). In the early Middle Ages, Danang was in strong competition with the southern province of Hoi An for fishing activities and maritime trade, but after the 15th century, technical progress in the construction of deep-draught ships quickly pushed Danang to the forefront of strategic ports for trade and warfare [START_REF] Duong | Histoire de la ville de Danang. Danang : Essai collectif[END_REF]. In the 18 th century, optimizing the natural advantages of the site, Danang became the largest commercial port in the central region of the country. Thanks to the imperial Nguyen dynasty, it became a base for the defense of the country. During the French colonial period, the peninsula was identified as a gateway to the Far East, playing a fundamental role in the first phase of the expansion of the city -then called Tourane. Thus, the architecture, the organization of the streets (Cornudet Act) and functions at the beginning of the 20th century were oriented towards the development of craft, industrial and commercial activities. In 1967, Danang was the political and military center for the South-Vietnamese Government and for the American army. Initiated by the U.S. Marines, the city is equipped with a military-industrial complex and modern infrastructure: a former military airport now converted to an air terminal, port and industrial areas, hangars and warehouses, road construction. Communications infrastructure and banking services then developed for companies involved in the production of oxygen, acetylene, detergents and textiles. However, as a tactical zone and border city on the 17th parallel during the devastating Vietnam War, Da Nang was confronted with a massive influx of refugees from the countryside resulting in large slum areas, and for several decades Danang lost its status of economic center. Until Doi Moi (reform) was introduced in 1986, Danang remained an under-developed provincial city. In 1996, the province of Nam Danang was divided in two, and Danang became a municipality under the direct control of central Government. The city then focused on its tourism potential to ensure its economic development.

The development of tourism in Danang: an indicator of emergence

For Gabas and Losch (2008: 25), the notion of "emergence", which changes constantly and has no standard definition, involves an implicit representation of the world; it expresses recognition of the status of a new entrant to the big league. Following this definition, Figuière et al. (2019: 10-11) observed that emergence is polysemous, multilevel and ephemeral in nature. In order to examine its benefit as a tool to understand the course of development of Danang city, it is necessary to define the indicators of emergence, which also change shape over time [START_REF] Bérenger | L'émergence : un processus évolutif et protéiforme[END_REF]. Here, we use the development of tourism as an index of the emergence of Danang.

The development of tourism has led to spatial transformations associated with planning and development strategies [START_REF] Kadri | La mise en tourisme : un concept entre déconstruction et reconstruction[END_REF] and urban policies (Cazes & Potier, 2002). The recent rise of Danang is largely due to the commitment of the former dignitary Nguyen Ba Than, but also to the involvement of numerous international and local stakeholders [START_REF] Philip | Danang, nouveau dragon économique du Vietnam[END_REF]The Economist, 2015).

Through his role as facilitator, Nguyen Ba Thanh established a direct line of communication between tourism industry stakeholders, the public sector, and local communities, recognizing their interdependence. He created a coalition of key stakeholders, including official tourism organizations in the domains of accommodation and the restaurant sector, as well as tourism and transport intermediaries. Not only did he have regular up-to-date information about tourists and the State resources provided to the tourist sector, he also had the power and the influence needed to obtain details of investment planning for infrastructure work and tourism development projects [START_REF] Hoang | Factors affecting the decision of the selection of foreign tourists for a tourist destination: A study in Danang City, Vietnam[END_REF].

The work of Nguyen et al. (2018) reveals the contribution of Nguyen Ba Thanh to a shared vision and the pragmatic construction of a consensus on the plans, objectives and actions to develop tourism in Danang (London, 2015). This action for cooperation between stakeholders in the sector was decisive, given the low level of confidence in private enterprises at the time and the political decision-makers' lack of knowledge of the tourist industry (Ibid., 2018). Today, air and sea transport infrastructure facilitates tourist access to Danang. First, the airport, located 5 km from the city center and with its two terminals, one for domestic and one for international flights, has become the third largest airport of the country with more than 1.5 million passengers per year (Iata, 2019). The airport management authority aims to increase the number of direct flights operated by international airlines, mainly from accommodation capacity increased four-fold, from 8,700 to more than 35,900 beds. Coastal development for tourism is the result of investment by both franchised international professionals and local independent entities. Two trends can be identified, creating a socio-spatial divide: luxury hotels or massive condo-hotels with 200 to 400 rooms on the sea front (e.g., Mélia, Sheraton, Hilton), and homestay and more modest hotels on the other side of the coast road.

In 2018, there were 7.6 million visitors to the city per year, of whom 60% were Vietnamese and 40% foreign (figures of the Danang Tourist Department, March 2019). However, tourism development is not limited to the visible metamorphosis characterized by urbanization and scheduled infrastructure construction [START_REF] Richins | Environmental, cultural, economic and socio-community sustainability: a framework for sustainable tourism in resort destinations[END_REF]; it also has a considerable effect on the Danang population, and it has been the vector of funding that has added to the transformation of the city. Spatially, this approach led to the creation of the Danang Hi-Tech Park (DHTP) in 20104 . Situated north west of the urban area, close to the motorway, new housing areas and the future industrial port, this multipurpose project combines office space, manufacturing and logistics zones, transportation facilities, a residential area, and recreational activities. With a surface area of 1,200 hectares, DHTP should become a catalyst of industrial R&D. Although the project appeared to have stalled, the Deputy Prime Minister, Vu Duc Dam, nonetheless declared at a recent business seminar that the Vietnamese Government had chosen DHTP as a pilot zone for the development of start-ups and innovation [START_REF] Le | Danang seeks investment in Hi-Tech Park[END_REF]. At the same time, the Danang PC increased its partnerships with leading metropolises, such as Tokyo, Seoul and Hong Kong where there were already collaborations in other domains (banking, urbanism, etc.), hoping to obtain assets in terms of the knowledge economy. Finally, twenty-three "third places" have been created since 2016 (fig. 7), revealing the emergence of a bottom-up, collaborative trend contributing to the creative economy (field work and interviews, February to May 2019). These third places come in different forms, with an increasing number of coworking spaces (22 in total) and a fablab. Their business strategies are also different, depending either on foreign ICT firms such as Samsung in S-Hub, shared-office developers such as Regus IWG, semi-public investment for the Municipal Library, or private commercial bottom-up management for the Enouvo Coworking Space. The coworking spaces also vary between multiple users at The Embassy (downtown café-restaurant) to occupancy of a whole floor in the Indochina Riverside Office Tower.

The challenge of technological innovation and strategic urban alliances

Finally, the type of building and neighborhood they occupy varies according to the geographical location; for example, the heritage and cultural district in the Hai Chau district on the left bank of the Han River, the central business district, or the affluent European and Korean expatriate neighborhood north of Thanh Khe. The managers of these coworking spaces seek to create synergies with other similar spaces in the cities of Can Tho and HCMC, to join national-level collaborative networks, and to create international partnerships, for example with the University of Arizona.

Strategies and stakeholders of aspirational urbanism

Danang is regularly ranked at the top of several lists [START_REF] Philip | Danang, nouveau dragon économique du Vietnam[END_REF]: it has exceeded the average rate of annual growth in Vietnam for 20 years; it ranks 5 th on the Provincial Competitiveness Index5 (with 67.65 out of 100 points), above Hanoi (in 9 th position, 65.40 points) and HCMC (10 th position, 65.34 points) (Vcci-USaid, 2018;[START_REF] Linh | Indice de compétitivité provinciale 2012 : les nouvelles figures de proue[END_REF]; one of the most livable places in Asia. These results are based on several factors, linked both to the political situation and to the personality of Nguyen Ba Thanh. His temperament, together with a favorable political situation, enabled him to take initiatives for successful management of the city. For example, in 1997 he was able to take advantage of a national agreement whereby the State allowed greater flexibility in the application of national policies at the local level (Ngoc, 2015). The members of the PC were also president and vice-presidents of the People's Council, making it easier to transfer the suggestions and political solutions to the administration. In 2004, he created the Danang Young Officials Club, composed of rising civil servants under 40 years of age and who he considered to have the potential to occupy local management posts, replacing former civil servants [START_REF] Nguyen | Influences on the policy process in local government in Vietnam: the case of low-income housing policy in Danang City from 2005 to[END_REF].

Efficient operational planning

Between 1996 and 2020, the physical transformation of Danang was the result of gradual urban sprawl [START_REF] Dang | Sử dụng ảnh Landsat đa thời cứu biến đô của thành phố Đà Nẵng phục vụ quy hoạch bảo vệ môi trường đô thị[END_REF] in three main strips (fig. 3): the "core strip" corresponding to the central part of the city; the "mainland strip" on the western and southern coastal areas, and the "eastern strip", which is an outlying area of urban development. This transformation can be explained by a succession of aspirational policies enabling the development of transportation infrastructure and improvement of the spatial layout of the city. In 1997, in order to reduce the effects of the River Han that constituted a strong dividing line between the urban center and the outlying rural fringes, Nguyen Ba Than engaged firms for the construction of the swing bridge to connect the two banks (Hang, 2018: 102). This structure laid the foundation for the changes initiated by the City Development Master Plan in 2002 6 . Hang (2018: 96) described how a slum clearance plan was carried out to meet the everyday needs of the population, particularly along the River Han (Danang Ccco 2016). The municipal area was urbanized very rapidly, with the renovation of 600 roads, streets and alleys, and the construction of nine other bridges (fig. 4). [START_REF] Gueorguiev | Keeping your head down: Public profiles and promotion under autocracy[END_REF] attributed this morphological metamorphosis of Danang partly to the remarkable charisma of Nguyen Ba Than, and partly to his ability to convince private companies, public authorities and the inhabitants of the positive outcomes expected of these "Five No" and then "Three Have" programs 7 , which have since been cited as an example in Vietnam and picked up by international funders (World Bank, Asian Development Bank, JICA, etc.) (VietnamNews, 2017). In this way, 3,000 hectares of slums were cleared and replaced by new urban zones (Nguyen et al., 2018). share of GDP also rose (from 3.81bn euros in 2018 to 4.14bn euros in 2019); GDP per capita also rose to 3,680 euros 9 (Gso Danang, 2019: 5-6; 37).

Ambitious but unfinished metropolitan projects

The urban authorities are pursuing the previous strategy, aiming to make Danang a hub of regional expansion, and to position it among the leading Asian cities, following the example of urban development in Singapore (interview with an architect-urban planner of Danang, March 2019).

6 Decision N°465/QD-TTg dated 17 June 2002. 7 The 5-No campaign carried out in Danang from 2000 to 2005 had five components: no hunger, no illiteracy, no homelessness, no drug addiction and no crime. Drawn up in May 2005, the 3-Have policy aimed to ensure that all citizens had a home, that all workers had a job, and that all inhabitants had a civil lifestyle. 8 Foreign Direct Investment (FDI) increased from 400 million euros in 1997 to 790 million euros in 2006. 9 By comparison, GDP per capita in HCMC was €5,717. 10 However, the diversity of goals and a new team in the PC made it difficult to raise sufficient capital to complete the projects, and also resulted in a lack of leadership and consensus among the stakeholders.

The new Master Plan 2030 Vision 2050 (Dupi, 2013), adopted following cooperation with Japan (Jica, 2010) and Korea (Seoul Institute et al., 2013), promoted infrastructure development and urban programs, but without the funds required to carry out many projects (field study, March 2019;Afd, 2017). Spatially, this plan shows the desire to strengthen the existing centrality of the Hai Chau district, through the creation of an original skyline, and to develop the outlying district of Hoa Vang through scientific and university functions [START_REF] Nguyen | Réflexion sur la structure de l'espace urbain de Danang[END_REF]. In Hai Chau, the headquarters of the municipal council and the administrative center have been rebuilt and expanded on the original site, the hospital has been modernized, and a cultural and sports center has been created. Through this new plan (fig. 5), the PC encouraged the construction of Capital Square, comprising office buildings for banking, business and insurance, commercial centers and recreational areas. In this way, from 2014 to 2019, the townscape was transformed by the first emblematic 34-storey tower housing the headquarters of the municipal council, and by an increasing number of skyscrapers. The development of the Hoa Vang district, which should change its use from secondary residential to a new gateway to Danang, is one of the many unfinished projects in 2019 seeking funding. Regarding means of transport outside the city, there was an ambitious plan to move, resize and redesign infrastructure systems for a huge future (interview with an operations manager of Danang city-10 Land-for-Infrastructure (LFI) or Doi dat lay ha tang in Vietnamese, is a public-private partnership (PPP) created to remedy the lack of public funds for the infrastructure systems essential for development (transport, telecommunications, water, drainage, energy). Authorized since the Land Law amended by decision no. 10/1998/QH10 of 2 December 1998 on PPPs, the LFI makes it possible for land adjacent to the infrastructure or located elsewhere in the city to be conceded to the private companies that construct them, who can then sell them or use them for commercial and residential purposes. This tool, based on the idea of mutual benefits, is increasingly prevalent in Vietnamese cities, such as HCMC [START_REF] Nguyen | Land for infrastructure in Ho Chi Minh City : land-based financing of transportation improvement[END_REF].

province, April 2019), involving relocating the passenger railway station in the pericentral district of Lien Chieu, moving the military airport in Chu Lai district, separating freight and tourism functions in the river and sea ports, construction of 7 new nautical resorts, 8 bus rapid transit (BRT) lines, and 3 metro lines.

In August 2019, with a view to promoting a sustainable and livable lifestyle (interview with a member of the Danang PC, February 2019), the city appointed a Singaporean consultant, Surbana Jurong, to design a new plan based on the generic model of green cities, like many South Asian and Chinese cities (Lorain & Curien, 2018;[START_REF] Leducq | Green city model as an urban strategy: Hanoi between international practices and local assemblage[END_REF]. This approach seems to be a response to the sudden drop in urban investments, a way of attracting new property developers and private capital.

Through resolution no. 393/QD-TTg of 18 March 2020, the Prime Minister, Nguyen Xuan Phuc, validated the changes to the Danang Master Plan 2030-2050 so that the development policies of the city-province could be included in the national strategy of socio-economic development for the whole of Vietnam.

Collaborative urban design trial

The collaboration of citizens, as stakeholders, in the planning and local government policy-making process aims to encourage people to put their tacit knowledge or user expertise toward the benefit of their city's development. Still very limited in Vietnam, the use of the participatory urban planning tool in Danang is socially and organizationally innovative, going beyond the call for fund-raising to improve the city's image in the late 1990s. For instance, citizens were invited to take part in the ideas competition for the twenty-one urban projects launched as part of the Danang Master Plan 2030-2050.

However, the urban authorities of Danang are only partially successful in achieving this goal of inclusive urban planning. In fact, the city shows signs of an economic down-turn, highlighted by several experts (Gso Danang, 2019), and it is increasingly exposed to the challenge of strong environmental constraints that need to be overcome.

Increasing number of challenges to overcome unfinished metropolitan aspirations

Extending the literature on South-East Asian studies, this section identifies at least three main elements that explain the gap between the theoretical and planned transformation of Danang, a secondary city of Vietnam, into a real regional metropolis. Desynchronized urban planning, and the gap between public policies and private interests, also show the failure of aspirational urbanism.

Uncertainty about the budget situation

During the period 2004-2016, Danang was given strong budgetary support by the State, enabling it to invest up to 32% of its GDP for infrastructure construction (Gso Danang, 2019: 37). Nevertheless, there was little land available to attract investors, and the revenue from land tax, which represented 40% of the overall revenue base for the period 2005-2010, now only accounts for 10% (Ibid., 2019;[START_REF] Bony-Cisternes | Collectivités locales et développement urbain au Vietnam : approches juridiques et pratiques de la décentralisation[END_REF]. Moreover, faced with increased fiscal pressure from the Government and financial recentralization, Danang has seen a 17% drop in its fiscal revenue. This situation has slowed down flood control measures and development of the DHTP.

Greater environmental risks

While tourism development can be an asset [START_REF] Cosaert | Le tourisme au centre du Vietnam. Des atouts importants, une mise en valeur délicate[END_REF], the number and size of sea-front hotels is exacerbating coastline erosion [START_REF] Son | Sạt lở nghiêm trọng hàng trăm mét bờ biển Đà Nẵng[END_REF][START_REF] Ngoc | Generative forces shaping the traditional city: the case of Hoi An, Vietnam[END_REF]. Poor drainage in the 100-meter coastal strip also prompted the Minister for Construction to observe that the current system of waste water collection and treatment does not meet the needs of the growth of tourism and urban services in the Danang region (Van, 2019). And yet the city is vulnerable to climate change, with increased tropical storms, depressions and typhoons (Ihmen, 2013). The continuing rise in sea level is leading to salinization of the rivers and more and more floods and landslides. Further away, the district of Son Tra, 10 km from the city center, regularly experiences a shortage of drinking water. In 2019, the private Danang Urban Environment Joint Stock Company supplied homes and hotels from tank trucks at an exorbitant price [START_REF] Chau | khách sạn, chung cư cao cấp ở Đà Nẵng phải mua nước sinh hoạt giá cao gấp 10 lần[END_REF]. The PC sought solutions that preserved tourism more than biodiversity. However, tourist accommodation projects that had for a time been considered in the Son Tra nature reserve were halted because they did not comply with the project for recognition as a Unesco World Heritage site [START_REF] Lippold | Resource assessment and development impact on douc population at Son Tra Nature Reserve. Vietnam[END_REF]. Over and above tourism, it is current urbanization that is causing the problems of ecosystem balance due to poorly controlled urban sprawl and persistent poor practices, such as the use of rare virgin land.

Desynchronized spatial planning

As stressed by the director of the Danang Department of Natural Resources and the Environment, nearly all the environmental protection black spots are due to a lack of spatial planning [START_REF] Dinh | Đà Nẵng đang gánh hậu quả từ quy hoạch không dự báo. 1thegioi[END_REF]. This is due to economic interests, and there is no strategy to monitor the pace of urbanization and projects, which leads to constant, arbitrary adjustments. The lack of synchronism and long-term vision results in illegal and constant modification of the destination of land made available to private investors [START_REF] Cafeland | La planification urbaine manque de visibilité et les conflits fonciers sont de plus en plus complexes, 28 august[END_REF]. Indeed, the Land-for-Infrastructure tool is not clearly regulated, while it has become a key factor of the growth of property investment around the transport corridors, fed by the flow of capital from South Korea, Japan and continental China [START_REF] Sehyung | The neighborhood effects of new road infrastructure: Transformation of urban settlements and resident's socioeconomic characteristics in Danang, Vietnam[END_REF]. Danang has neither the human resources for managing technical and environmental issues, nor the appropriate regulation and strategic planning tools.

Regarding the DHTP, which is one of the pillars of development of Danang, there has been an accumulation of delays resulting in a low rate of occupation of approximately 25.2%. Likewise, in the Hoa Khanh industrial zone, problems of electricity and water supply and recurring floods have also slowed growth [START_REF] Chan | Nẵng: có giải pháp ổn định giá thuê đất lâu dài trong các khu công nghiệp, khu công nghệ cao[END_REF]. Moreover, companies are faced with a lack of stability of land rental costs in the business parks, which are adjusted every year by the industrial and high-tech park management board.

The rapid increase in condo-hotel projects comfortable real-estate income for the Vietnamese investors Vingroup or Sungroup, the developer of the vast Ba Na Hills resort, while displacing lower-income households. Projects like Sunrise Bay give the impression that the city has been privatized to the benefit of real-estate groups, who are alone in their ability to finance the DHTP, air and maritime infrastructure, or the extension of the new KDTM urban zones that figure in the Master Plan 2030-2050. Nevertheless, several real-estate projects have been abandoned following protests by the people of Danang about increasing socio-environmental inequalities [START_REF] Tuoi | Đà Nẵng nhiều lần ra 'tối hậu thư' vẫn khó thu hồi 30 khu đất vàng. 12 février[END_REF].

For example, fishing areas have been reduced, leading many fishermen to lose their jobs (fig. 8), and residents have observed the increasing scarcity of open public spaces.

Conclusion

This article highlights the urban metamorphosis of Danang, a secondary city, through the lens of a strategy of emergence and aspirational urbanism. The interplay of various stakeholders led to economic and land policies encouraging several forms of centrality: regional and urban, touristic and economic, technological and digital. However, Danang, which now holds a key position in Vietnam, has two major weak points: unpredictable development of plans and projects, and poor regulation leading to ecosystem degradation. At the same time, while financial internationalization has opened up new horizons for financing infrastructure systems, it has also added to dependence on Foreign Direct Investment (FDI), partly explaining why growth-generating projects have been subject to fluctuating development and delays of several years. This paper thus aims to fill a gap in the literature regarding the urban planning of secondary cities, with theoretical and practical implications. Recently, the very large private developers in Hanoi and HCMC have also started investing in road infrastructure and in property and commercial projects, taking advantage of Danang's public metropolitan action to boost their own growth strategy. Further research on Danang's capacity to become a regional metropolis should examine the means whereby the urban authorities can go beyond local policies and the central

Fig. 1 .

 1 Fig. 1. View of urban landscape transformation Source: Authors, 2019.

Fig. 2 .

 2 Fig. 2. Danang in the urban hierarchy of Vietnam Source: Authors, 2021.

  Southeast and East Asia (Seoul with Korean Air and Asiana Airlines; Guangzhou and Beijing with China Southern Airlines; Singapore and Osaka with Jetstar Asia Airways; as well as regular flights to Tokyo, Macau, Hong Kong, Bangkok and Singapore). Recently, Qatar Airways opened a flight from London and Paris to Danang via Doha. Secondly, the Tien Sa terminal in the deep-sea harbor serves 145,000 cruise passengers per year (Danang Port Authority, 2019). Between 2011 and 2019,

  Another strategic focus of the Master Plan 2030-2050 was to make Danang a modern, smart city based on the development of Information and Communication Technologies (ICT), which have existed in the city since the installation of the American military/industrial complex during the Vietnam War. The aim was to encourage the implementation of digital technology, both for urban management and to support local economic development. In 2010, the Danang PC established several partnerships with international leaders in the software sector, positioning their region at the cutting edge of digital technologies. A memorandum of understanding on digital cooperation was signed by Danang City and IBM Vietnam. In 2011, with the support of Intel, Danang joined the Open Data Centre Alliance (ODCA) to connect all municipal data online. In 2012, as part of the World Bank's Ecocities program, it entered into a partnership with CISCO Systems for technological management of flows (goods, people, information). Likewise, trade agreements were also concluded with Vietnamese companies in the sector (VNPT, Viettel) to optimize electricity and telecommunication networks and to make Wi-Fi accessible throughout the area. In this way, by 2014 Danang had become one of the three pilot cities of the Vietnamese Government's smart city plan(Leducq et Scarwell, 2018b: 307; Courmont & Le Galès, 2019), alongside Hanoi and HCMC.

Fig. 7 .

 7 Fig. 7. Three types of coworking spaces: (a) IT incubator, (b) traditional business diversification, and (c) based on relational collaboration, in the central district of Thanh Khe Source: Authors, 2019.

Fig. 3 .

 3 Fig. 3. Urbanization of Danang between 1996 and 2020

Fig. 4 .

 4 Fig. 4. Network of roads and bridges connecting the districts of Danang City: (a) Yet Kieu, road to the seaport, (b) Cau Rong, Dragon bridge, (c) Cau Thuan Phuoc, northern bay of Danang Source: Authors, 2019.

Fig. 5 .

 5 Fig. 5. Renovated city center with (a) high-rise building, and (b) the iconic city hall square Source: Authors, 2019.

Fig. 6 .

 6 Fig. 6. Location of urban and property projects in the Master Plan 2030-2050 Source: Authors, 2020.

Fig. 8 :

 8 Fig. 8: Decrease in fishery activities Source: Authors, 2019.

Vietnamese provinces are governed by a People's Council elected by the citizens, assisted by a People's Committee (PC), which is the executive arm. This local organization is modeled on that of Central Government.

Decision No.1979/QD-TTg of 28 October 2010.

Created in 2005 by the Vietnam Chamber of Commerce and Industry (VCCI) and the United States Agency for International Development (USAID), the index is revised annually for the

provinces of Vietnam. It measures the ease of doing business for companies and investment possibilities. Its ultimate aim is to enable the provinces to identify their strengths and weaknesses, in order to draw up policies for investment, job creation and sustainable development.

power of Hanoi. It would also be useful to analyze the emergence of new alliances that focus on mobilizing the financial resources required to carry out the projects, while also contributing to better acquisition and integration of technical and human skills for efficient management of a coast that is under pressure.

This work was supported by the Regional Council of Centre-Loire Valley through the research program COWORK-CVL.


Manon Clairbaux
email: clairbauxm@gmail.com

Paul Mathewson

Warren Porter

Jérôme Fort

Hallvard Strøm

Børge Moe

Sebastien Descamps

Hálfdán Helgason

Vegard S Bråthen

Benjamin Merkel

Tycho Anker-Nilssen

Ingar S Bringsvor

Olivier Chastel

Signe Christensen-Dalsgaard

Jóhannis Danielsen

Francis Daunt

Nina Dehnhard

Kjell Einar Erikstad

Alexey Ezhov

Maria Gavrilo

Yuri Krasnov

Magdalene Langset

Svein H Lorentsen

Mark Newell

Bergur Olsen

Tone K Reiertsen

Geir Systad

Thorkell L Thórarinsson

Mark Baran

Tony Diamond

Annette L Fayet

Michelle G Fitzsimmons

Morten Frederiksen

Hugh G Gilchrist

Tim Guilford

Nicholas P Huffeldt

Mark Jessopp

Kasper L Johansen

Amy Lee Kouwenberg

Jóhannis F Linnebjerg

Heather L Major

Laura Mcfarlane Tranquilla

Mark Mallory

Flemming R Merkel

William Montevecchi

Anders Mosbech

Aevar Petersen

David Grémillet
email: david.gremillet@cebc.cnrs.fr

North Atlantic winter cyclones starve seabirds

Each winter the North Atlantic Ocean is the stage for numerous cyclones, the most severe ones leading to seabird mass-mortality events called 'winter wrecks' 1-3 . During those,

thousands of emaciated seabird carcasses are washed ashore along European and North American coasts. Winter cyclones can therefore shape seabird population dynamics [START_REF] Frederiksen | The demographic impact of extreme events: stochastic weather drives survival and population dynamics in a long-lived seabird[END_REF][START_REF] Guéry | Winter extratropical cyclone influence on seabird survival: variation between and within common eider Somateria mollissima populations[END_REF] by affecting survival rates as well as the body condition of surviving individuals and thus their future reproduction. However, most often the geographic origins of impacted seabirds and the causes of their deaths remain unclear [START_REF] Morley | The seabird wreck in the Bay of Biscay and Southwest Approaches in 2014 : A review of reported mortality[END_REF] . We performed the first ocean-basin scale assessment of cyclone exposure in a seabird community, by coupling winter tracking data for ~1500 individuals of five key North Atlantic seabird species (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla) and cyclone locations. We then explored the energetic consequences of different cyclonic conditions using a mechanistic bioenergetics model [START_REF] Porter | Method and system for calculating the spatialtemporal effects of climate and other environmental conditions on animals[END_REF] and tested the hypothesis that cyclones dramatically increase seabird energy requirements. We demonstrated that cyclones of high-intensity impacted birds from all studied species and breeding colonies during winter, but especially those aggregating in the Labrador Sea, the Davis Strait, the surroundings of Iceland and the Barents Sea. Our broadscale analyses suggested that cyclonic conditions do not increase seabird energy requirements, implying that they die because of the unavailability of their prey and/or their inability to feed during cyclones. Our study provides essential information on seabird cyclone exposure in a context of marked cyclone regime changes due to global warming [START_REF] Christensen | Climate phenomena and their relevance for future regional climate change[END_REF] . Keywords: At-sea distribution, Cyclones, Energy expenditure, GLS tracking, Seabird migration, Seascape ecology

Results

Cyclone-induced seabird mortality adds to other threats such as habitat loss, invasive species or interactions with fisheries, contributing to the general downward trend of the global seabird community [START_REF] Grémillet | Persisting worldwide seabird-fishery competition despite seabird community decline[END_REF] and making them one of the most threatened bird groups [START_REF] Dias | Threats to seabirds: A global assessment[END_REF] . It is therefore essential to understand the causes of seabird mortality during cyclones, and to identify factors contributing to contrasting spatio-temporal mortality patterns at the seabird-community level.

Multiple seabird species from different breeding colonies may inhabit different wintering areas [START_REF] Frederiksen | Migration and wintering of a declining seabird, the thick-billed murre Uria lomvia, on an ocean basin scale: Conservation implications[END_REF][START_REF] Fayet | Ocean-wide drivers of migration strategies and their influence on population breeding performance in a declining seabird[END_REF] , and this may strongly affect the composition of seabird winter wrecks. In this context, community-wide analyses are lacking due to the technical difficulties of studying seabirds wintering far out at sea under harsh conditions.

Winter cyclone exposure of the North Atlantic seabird community

The North Atlantic Ocean and adjacent seas (100°W-100°E, 30°N-90°N, see Figure S1) is the stage for numerous winter cyclones (October to February) (see Figure S2), which are defined by the National Hurricane Center, as large-scale air masses that rotate around a center of low atmospheric pressure. Their locations between 2000 and 2016 were obtained from climatic reanalysis data (see STAR Methods). Using the Dvorak storm classification [START_REF] Dvorak | Tropical cyclone intensity analysis using satellite date[END_REF] we sorted them across their duration into one of the four classes of cyclone intensity defined (see STAR Methods). Calculating, for each month, the average number of cyclones of each category for each 250 km grid cell, we demonstrated that a limited number of localized low intensity cyclones (Class 1 and 2) occurred mainly in the Baffin Bay, the Gulf of Maine and the Mediterranean Sea regions (see Data S1A). Class 3 cyclones were more numerous and widespread, particularly in October and November, and mainly occurred in the Baffin and Hudson bays, the Davis Strait, the Labrador Sea, east off Newfoundland, around Iceland and in the Barents Sea. Finally, Class 4 cyclones were observed in all winter months off west Iceland, the Norwegian coast and in the Barents Sea, whereas the Davis Strait and the Labrador Sea were only affected by Class 4 cyclones between December and February.

Winter bird locations were obtained from Global Location Sensors (GLS) deployed and retrieved during the breeding season on 1532 individuals from 39 breeding colonies across the North Atlantic Ocean (see STAR Methods and Table S1). We approximated core use areas for each colony and species during the winter months, calculating monthly utilization distributions (UD) with the BRB-MKDE software ( 14 , see STAR Methods). To conclude on seabird cyclone exposure, we overlapped cyclone locations with core wintering areas of different seabird species and populations (see Figure 1, Data S1A-S1F), before calculating an average cyclone exposure index (see Figure 2 and STAR Methods).

Low intensity cyclones (Class 1 and 2) showed limited overlap with the seabird community.

However, birds from all species and colonies were likely to encounter Class 3 and 4 cyclones during winter, with substantial inter-annual variability in the mean number of such events occurring within seabird core use areas (Figure 1 and Data S1B-S1F). Notably, seabirds from Canadian, Greenlandic and Icelandic colonies were exposed to Class 3 and 4 cyclones in the Davis Strait, the Labrador Sea and off Newfoundland, while Norwegian and Russian seabirds were likely impacted by those occurring in the Barents Sea. In contrast, Class 3 cyclones were fewer in the mid-west Atlantic Ocean and were more likely to spare seabirds wintering there (see Data S1A). Due to major seabird aggregation and the marked presence of Class 3 and 4 cyclones, areas such as the Labrador Sea, the Davis Strait, the vicinity of Iceland and the Barents Sea are predicted as sources of major winter wrecks (Figure 2).

Seabird energy requirements under cyclonic and non-cyclonic conditions

Necropsies suggest that seabirds are lean after being exposed to high-intensity cyclones [START_REF] Morley | The seabird wreck in the Bay of Biscay and Southwest Approaches in 2014 : A review of reported mortality[END_REF][START_REF] Jones | Physical condition of auks beached in eastern britain during the wreck of february 1983[END_REF] and that the resulting mortality can be aggravated by mercury contamination [START_REF] Fort | Mercury in wintering seabirds, an aggravating factor to winter wrecks?[END_REF] .

Yet, we do not know whether they starve due to abnormally high-energy expenditure linked to harsh climatic conditions [START_REF] Fort | Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic[END_REF] , because of reduced foraging profitability and energy inputs, or because both these constraints synoptically affect their energy balance. Recent research has shown that seabirds wintering in the North Atlantic Ocean track environmental gradients to remain in an energetic steady state [START_REF] Amélineau | Energyscapes and prey fields shape a North Atlantic seabird wintering hotspot under climate change[END_REF][START_REF] Fort | Biologging, remotelysensed oceanography and the continuous plankton recorder reveal the environmental determinants of a seabird wintering hotspot[END_REF][START_REF] Clairbaux | Meeting Paris agreement objectives will temper seabird winter distribution shifts in the North Atlantic Ocean[END_REF] , but how winter cyclones affect this delicate balance remains mysterious.

To test the hypothesis that cyclones dramatically increase seabird energy requirements, we modeled species-specific, monthly energy requirements for each winter between 2000 and 2016 on a 1000km*1000km area off North Newfoundland (see Figure S1), using the mechanistic model Niche Mapper TM (Porter & Mitchell, 2006, see STAR Methods) under four intensities of cyclones and under non-cyclonic conditions (see STAR Methods).

Following the protocol used by Grémillet and colleagues [START_REF] Grémillet | Cormorants dive through the Polar night[END_REF] , we calculated how many days each of the five studied species could fast before dying, when exposed to Class 2, Class 3 and Class 4 cyclones in the studied area (see STAR Methods). Statistical analyses revealed several significant differences (Kruskal-Wallis, p<0.05) in seabird energy requirements (see Table 1) between the six categories of conditions tested (Class 1 to 4 cyclones, non-cyclonic conditions with usual seabird flight/diving activities, non-cyclonic conditions with cyclonic seabird flight/diving activities). In a very limited number of cases, cyclonic conditions led to increases (up to 36%) in seabird energy requirements in comparison with non-cyclonic conditions with cyclonic flight/diving activities (post hoc Dunn's test, p<0.05). Surprisingly, we found that seabird energy requirements were generally similar or lower during cyclones, compared to non-cyclonic conditions (see Figure 3 and Data S1G-S1K). In particular, for little auks and black-legged kittiwakes, energy requirements were generally significantly lower during Class 2, 3 and 4 cyclones than during non-cyclonic conditions experienced with usual flight/diving activities (post hoc Dunn's test, p<0.05). Those differences were not significant for deep divers (except for Atlantic puffins in October and December under specific cyclonic conditions) (see Table 1). Further, seabird energy requirements were not significantly different during Class 1 cyclones than for non-cyclonic conditions experienced with usual flight/diving activities (post hoc Dunn's test, p<0.05).

Energy requirements under Class 2, Class 3 and Class 4 cyclones were not significantly different (see Data S1G-S1K) and these classes were therefore pooled when calculating fasting endurance. Between October and December, average fasting endurance was 2.2 days (+/-0.1) for little auk and 6.5 days (+/-2.5) for Atlantic puffins while black-legged kittiwakes, Brünnich's guillemots and common guillemots could fast 8.4 days (+/-0.5), 7.3 days (+/-0.06) and 8.1 days (+/-0.1), respectively. With winter's advance, these durations dropped respectively to 1.6 days (+/-0.1), 4.6 days (+/-0.6), 6.4 days (+/-0.5), 5.9 days (+/-0.6) and 6.3 days (+/-0.7), between January and February.

Discussion

We demonstrated that seabirds wintering in areas such as the Labrador Sea, the Davis Strait, the vicinity of Iceland and the Barents Sea, are particularly exposed to cyclones.

Crucially, our broad-scale analyses led us to reject our hypothesis: climatic conditions experienced by seabirds during cyclones generally did not enhance their energy requirements.

These results suggest that seabird mortality during winter high intensity cyclones is likely caused by starvation due to the unavailability of prey and/or their incapacity to feed.

Mechanistic insights into storms impacts on seabirds

Our surprising conclusion regarding death causes in seabirds exposed to cyclones is in agreement with a study conducted on greater flamingos (Phoenicopterus roseus) during cold spells in the Camargue, France 22 : Thousands of flamingos died, not because of hypothermia but due to inaccessible food in frozen salt pans. Conversely, our results contrast with former modeling work which pointed to weather-induced energetic bottlenecks in seabirds wintering in the North Atlantic Ocean [START_REF] Fort | Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic[END_REF] . Birds were predicted to experience markedly higher thermoregulatory costs in December, because of lower air and water temperatures, and higher wind speeds. Yet this previous study investigated seabird energetics at the scale of months, whereas cyclones affect them at the scale of days. In this context, little auks appear as particularly vulnerable to fasting induced by cyclones, because of low lipid reserves and high mass-specific energy expenditure, likely explaining extensive and recurrent winter wrecks on North American coasts near their main wintering grounds [START_REF] Stenhouse | Winter distribution and wrecks of little auks (dovekies) Alle a.alle in the Northwest Atlantic[END_REF][START_REF] Lucas | Beached bird surveys on Sable Island, Nova Scotia, 1993 to 2009, show a decline in the incidence of oiling[END_REF] . Other species were predicted to cope with relatively longer fasts, but remain vulnerable to prolonged cyclonic conditions especially at the end of winter. Therefore, recurrent cyclones affecting a specific area/seabird population are predicted as strong drivers of winter wrecks. What exactly prevents seabirds from feeding during cyclonic conditions remains unclear. One possibility is that cyclones may enhance water turbidity, decrease underwater light intensity, and perturb prey patches and vertical migration. Potentially disrupting water stratification, cyclones may modify prey aggregation and negatively impact seabird foraging efficiency [START_REF] Meyer | Oceanic thermal structure mediates dive sequences in a foraging seabird[END_REF] .

Therefore, this 'washing-machine effect' could strongly affect seabirds feeding within the 50 upper meters of the water column, such as black-legged kittiwakes and little auks in our study. Further, cyclones and associated disturbances alter underwater soundscapes and thus constrain the detection of acoustic cues by seabirds, being from conspecifics, prey or predators [START_REF] Hansen | Great cormorants (Phalacrocorax carbo) can detect auditory cues while diving[END_REF][START_REF] Thiebault | First evidence of underwater vocalisations in hunting penguins[END_REF] . Prey could also occur deeper in the water column during cyclones as already observed for some elasmobranchs or teleosts [START_REF] Udyawer | Variable response of coastal sharks to severe tropical storms : environmental cues and changes in space use[END_REF][START_REF] Patterson | Movement of tagged red snapper in the Northern Gulf of Mexico[END_REF] , but how this impacts pursuit-diving species such as puffins and guillemots, is not known. By continuing to dive during cyclones, deep divers such as guillemots and puffins potentially take the risk of using energy reserves in an attempt to track inaccessible prey. However, common and Brünnich's guillemots have been observed switching their diet during strong winds, from schooling fish to amphipods or smaller sandeels, potentially targeting prey that required less underwater searching [START_REF] Elliott | Windscapes shape seabird instantaneous energy costs but adult behavior buffers impact on offspring[END_REF][START_REF] Finney | The effect of weather conditions on the feeding behaviour of a diving bird, the common guillemot Uria aalge[END_REF] .

Alternatively, cyclones may shift alcids away from their preferred prey patches and into unprofitable foraging habitats [START_REF] Wiley | The effects of hurricanes on birds, with special reference to Caribbean islands[END_REF] . Overall, even if starvation may be the main driver of seabird winter wrecks, we cannot exclude others causes of mortality, such as drowning [START_REF] Morley | The seabird wreck in the Bay of Biscay and Southwest Approaches in 2014 : A review of reported mortality[END_REF] , or collision with reefs and rocky coastlines (Mark Baran, personal comm) or inland stranding [START_REF] Wiley | The effects of hurricanes on birds, with special reference to Caribbean islands[END_REF] .

Potential limitations

Despite these advances, we recommend caution in interpreting our results as they are based on reanalyzed environmental data and on thermodynamic modeling. Notably, measuring empirical data is nearly impossible during cyclones. This calls for the use of modeling approaches to characterize these climatic events and their energy consequences for seabirds, but also constrains model outputs. This lack of in-situ measurements influenced NicheMapper TM simulations in two main ways. First, the behavior of pelagic seabirds is hard to assess under cyclonic conditions, and the animal module mainly relies on the assumption that North Atlantic seabirds significantly reduce flying and/or diving during cyclones. On a worldwide scale, while many seabird species exhibit avoidance behavior seeking coastal shelter and/or reducing activity levels during high-intensity cyclones [START_REF] Wilkinson | Tropical cyclones alter short-term activity patterns of a coastal seabird[END_REF] , others, such as great frigatebirds (Fregata minor) take advantage of cyclonic winds to save energy while gliding over thousands of kilometers [START_REF] Weimerskirch | Frigate birds track atmospheric conditions over months-long transoceanic flights[END_REF] . Such extreme gliders, which occur in the tropics and Southern Ocean, are rarer in the North Atlantic, an area dominated by alcid species in terms of abundance [START_REF] Barrett | Seabird numbers and prey consumption in the North Atlantic[END_REF] . This seabird family, which is morphologically adapted to using its wings for underwater propulsion, has high wing-loading, and very limited capacity to ride strong winds. Thus, cyclonic conditions dramatically increase flight costs in alcids [START_REF] Elliott | Windscapes shape seabird instantaneous energy costs but adult behavior buffers impact on offspring[END_REF] , and therefore tend to prevent them from flying.

Second, since direct measurements of environmental data during cyclones were lacking at the spatio-temporal scales needed for our analyses, we depicted cyclonic conditions in the microclimate module using a limited number of reconstructed data at a broad scale, potentially missing other relevant differences between non-cyclonic and cyclonic conditions.

Finally, due to a lack of available information, we only modeled the effects of temperature, wind speed and reduced activity on heat loss and energy requirements during cyclones, omitting other variables such as wind gust speed, water velocity, wave height, as well as other conditions potentially affecting seabird thermoregulation and thus their energy requirements.

For example, localized wind gusts, sea spray and high-speed precipitation could all reduce plumage insulation, thereby increasing seabird heat loss and energy requirements. Further, tall waves could require the birds to dive more frequently, increasing energy requirements. Thus, current predictions on seabird energy requirements during cyclones should be interpreted as likely conservative estimates. However, given the current lack of information, mechanistic models remain important tools to explore potential impacts, and to generate hypotheses that could be further investigated. Additional direct measurements could help to refine these modeling approaches and evaluate initial assumptions. For example, deploying electronic devices to study North Atlantic seabird 3D movements during cyclones is a key objective for future research, which will allow testing our assumption that these animals are less active under passing cyclones. Such deployments will also help infer additional energetic costs in seabirds floating across rough seas, especially if they try to dive under each wave and/or to stay in the same area rather than drifting away with surface currents (up to 2.5 m.s -1 under Class-4 cyclones [START_REF] Chang | Observed nearsurface currents under four super typhoons[END_REF] ). Finally, future efforts will allow researchers to take into account inter-and intra-individual morphological, physiological and behavioral variability across winter in seabird energetic modeling, improving output accuracy.

Despite these limitations, our study provides essential new knowledge, notably on the vulnerability of wintering seabirds to high intensity cyclones in the Labrador Sea, off Newfoundland, off southern Greenland, around Iceland, off the Norwegian coast and in the Barents Sea. These results are supported by the numerous seabird winter wrecks observed across years on beaches close to those areas [START_REF] Camphuysen | A review of the causes, and consequences at the population level , of mass mortality of seabirds[END_REF][START_REF] Morley | The seabird wreck in the Bay of Biscay and Southwest Approaches in 2014 : A review of reported mortality[END_REF][START_REF] Stenhouse | Winter distribution and wrecks of little auks (dovekies) Alle a.alle in the Northwest Atlantic[END_REF][START_REF] Lucas | Beached bird surveys on Sable Island, Nova Scotia, 1993 to 2009, show a decline in the incidence of oiling[END_REF][START_REF] Mcfarlane Tranquilla | High Arctic sea ice conditions influence marine birds wintering in Low Arctic regions[END_REF] (and Flemming Ravn Merkel personal communication about Brünnich's guillemot wrecks in south Greenland). Yet, as GLS-tracking is based on individuals who survived the non-breeding period, we cannot exclude the possibility that wrecked individuals wintered in different locations with higher cyclone exposure, even though seabirds are highly gregarious, also at sea. Further, the localization and study of winter wrecks on beaches is impacted by oceanic currents carrying seabird carcasses, and by the accessibility of these beaches to observers. This potentially leads to spatiotemporal mismatches between seabird wrecks as perceived by researchers and the general public, and areas of major winter high intensity cyclone impacts on seabirds offshore. Such a mismatch may explain why we found limited overlap between seabird winter distributions and cyclones in the Eastern Atlantic, despite the fact that large winter wrecks have regularly been recorded along the shores of Western Europe.

Seabird storm exposure under climate change

It is well-established that seabirds experience direct and indirect negative stressors from global warming [START_REF] Sydeman | Climate change and marine vertebrates[END_REF] . Since the 1970s, the frequency and intensity of the strongest tropical cyclones in the North Atlantic have increased markedly [START_REF]Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team[END_REF] . Considering future North Atlantic cyclone regimes, there are still uncertainties but model outputs predict some common features: There will be fewer cyclones in the future, but the frequency of the strongest ones is predicted to increase with global warming [START_REF]Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team[END_REF] . Moreover, cyclone tracks will likely shift northwards under climate change [START_REF] Tamarin-Brodsky | Enhanced poleward propagation of storms under climate change[END_REF] , increasing the storminess of Western Europe 41 and of the high Arctic [START_REF] Akperov | Future projections of cyclone activity in the Arctic for the 21st century from regional climate models (Arctic-CORDEX)[END_REF][START_REF] Benestad | Climate change and projections for the Barents region: What is expected to change and what will stay the same?[END_REF] . Since storm activity is positively correlated to the magnitude of seabird wrecks [START_REF] Tavares | Environmental predictors of seabird wrecks in a tropical coastal area[END_REF][START_REF] Tavares | Mortality of seabirds migrating across the tropical Atlantic in relation to oceanographic processes[END_REF] and the North Atlantic Ocean seabird community is also predicted to shift northwards, following its prey base [START_REF] Beaugrand | Prediction of unprecedented biological shifts in the global ocean[END_REF] , we infer that this community will become even more susceptible to mass mortality caused by winter wrecks. This might be particularly marked in areas such as the Bay of Biscay, the North Sea, the Norwegian and the Barents Seas. In this context, our study provides an essential conceptual and methodological framework to identify the vulnerability of specific populations to cyclone events at the scale of the North Atlantic Ocean.

Figures Figure 1: Average number of cyclones within the core use areas of common guillemot from different colonies between 2000 and 2016 in October.

Colonies abbreviations: Bjørnøya (BJ), Cape Gorodetskiy (CG), Faroe Islands (FI), Grimsey (GR), Hjelmsøya (HJ), Hornøya (HO), Jan Mayen (JM), Langanes and Skjalfandi (LaS), Latrabjarg (LA), Sklinna (SK). Error bars correspond to standard deviations capturing the variation between years. Results for other species, colonies and months are provided in Data S1B-S1F. Tables Table 1:

STAR Methods

Resources Availability

Lead contact

Further information and requests for resources and reagents should be directed to and will be fulfilled by the lead contact, Manon Clairbaux (clairbauxm@gmail.com).

Materials availability

This study did not generate new unique reagents.

Data and code availability

• Environmental variables, bird and cyclone location are publicly available online.

Physiological, behavioral and morphological characteristic of the species studied are available in the Table S2.

• All original code has been deposited at (http://dx.doi.org/10.17632/rzszr9fpt4.1) and is publicly available as of the date of publication. DOIs are listed in the key resources table.

• Any additional information required to reanalyze the data reported in this paper is available from the lead contact upon request.

Experimental Model and Subject details

We focused on the winter distribution of five seabird species (little auk (Alle alle),

Atlantic puffin (Fratercula arctica), common guillemot (Uria aalge), Brünnich's guillemot (Uria lomvia) and black-legged kittiwake (Rissa tridactyla)). These species, which account for ca. 75% of the total number of seabirds breeding along the North Atlantic Ocean [START_REF] Barrett | Seabird numbers and prey consumption in the North Atlantic[END_REF] are also among the most severely hit by winter high-intensity cyclones [START_REF] Camphuysen | A review of the causes, and consequences at the population level , of mass mortality of seabirds[END_REF][START_REF] Farque | Échouage massif d'oiseaux marins durant l'hiver 2014 sur la façade atlantique[END_REF] . Bird locations were obtained from Global Location Sensors (GLS) deployed and retrieved during the breeding season for 1532 individuals from 39 breeding colonies across the North Atlantic Ocean (see Figure S1 and Table S1). Birds were caught at the nest according to ethical approval from each country's appropriate organization.

Method details

Locations and characteristics of North Atlantic cyclones during winter

According to the National Hurricane Center, cyclones are defined as large-scale air masses that rotate around a center of low atmospheric pressure. Their locations were obtained from the 'Northern Hemisphere Cyclone Locations and Characteristics from NCEP/NCAR Reanalysis Data, Version 1' online dataset [START_REF] Serreze | Northern Hemisphere Cyclone Locations and Characteristics from NCEP/NCAR Reanalysis Data[END_REF] . Locations were calculated using the updated Serreze (1997) [START_REF] Serreze | Icelandic low cyclone activity: Climatological features, linkages with the NAO, and relationships with recent changes in the Northern hemisphere circulation[END_REF] algorithm on daily Sea Level Pressure from the National Center for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR)

Reanalysis data set in a 250 km grid. We focused on winter cyclones (October to February) in the North Atlantic and adjacent seas (100°W-100°E, 30°N-90°N) between 2000 and 2016.

Using the Dvorak storm classification [START_REF] Dvorak | Tropical cyclone intensity analysis using satellite date[END_REF] on the cyclone central pressure we defined four classes of cyclone intensity (> 1009 hPa = Class 1; 1005-1009 hPa = Class 2; 987-1005 hPa = Class 3; < 987 hPa = Class 4) and classified each cyclone in the studied area across its duration. Finally, for each month, we calculated the average number of cyclones of each category that occurred between 2000 and 2016 for each 250 km grid cell.

Winter distribution of seabirds

Two locations per day were obtained through the recorded light levels by Global

Location Sensors for each individual with an accuracy of +/-200 km [START_REF] Lisovski | Geolocation by light: Accuracy and precision affected by environmental factors[END_REF][START_REF] Phillips | Accuracy of geolocation estimates for flying seabirds[END_REF] . We focused on locations acquired during the winter period (October to February) and removed locations obtained during the two weeks on either side of the equinoxes [START_REF] Lisovski | Geolocation by light: Accuracy and precision affected by environmental factors[END_REF] as well as spurious locations and those falling on land. For each species, we then calculated monthly utilization distributions (UD) for each individual using the BRB-MKDE software ( 14 , March 2018 version for location in decimal degrees with hmin=250 km) before averaging by seabird colony and species. To avoid that some individuals drive the UD of the colony, we performed a kernel stability analysis and for each month, we only considered individuals which had a sufficiently large number of locations to satisfy this stability criteria. To perform this stability analysis we calculated for each individual and for each month (n/4) UD, with n the total number of locations (after quality and equinoxes checks) for the individual and month considered: the first UD was calculated with 4 locations, the second 8, the third one 12, etc.

until the total number of locations was included. Then, for each individual and for each month, we calculated the percentage of overlap between each UD and the UD obtained considering all the locations. Finally, for each species, we plot for each month the individual percentage of overlap against the number of locations included in the UD calculation and we visually determined the minimum number of locations needed to reach a high overlap percentage for the maximum of individuals. This threshold was set at 30 locations for little auks and black-legged kittiwakes and was set at 20 locations for Atlantic puffins, common and Brunnïch's guillemots. Therefore individuals having less locations than the number needed wasn't considered when averaging UD by colony and species.

We then used 25% utilization kernels to approximate areas of core use for each colony and species during the winter months (see Data S1A). For each month, we calculated the average number of cyclones of each category that occurred between 2000 and 2016 within each colony core use areas (Figure 1 and Data S1B-S1F). Finally, we interpolated each colony's UD on a 250 km grid before calculating, for each pixel, the following cyclone exposure index (CEI) for each wintering month:

( , ) = ( , ) × ( , )
where NC(i,j) is the average number of cyclones between 2000 and 2016 within the pixel i for the month j and UDT(i,j) is the sum, all species considered, of average UD of each colony for the pixel i and the month j. The monthly cyclone exposure indexes were then averaged to obtain a unique index for the wintering period (see Figure 2).

Modeling seabird energy requirements under non-cyclonic and cyclonic conditions

We used the mechanistic model Niche Mapper TM 7 to calculate energy requirements for each species under cyclonic and non-cyclonic conditions for each wintering month. Niche

Mapper TM is based on a microclimate model and an animal module: the microclimate model calculates hourly environmental conditions for the near surroundings of the bird and the animal module uses the resulting outputs together with bird morphological, behavioral and physiological properties to estimate the metabolic rate needed by the bird to maintain its body temperature at a given time with a specific behavioral time budget. We focused on a 1000 km

x 1000 km area off North Newfoundland (see Figure S1) where the five seabird species aggregate during winter. This area experienced numerous cyclones during the winter months between 2000 and 2016 (see Figure S3). For each of them, we extracted environmental were sourced from the literature (see Table S2) and obtained through dedicated measurements. Specifically, we set the proportion of time spent flying per day during winter under non-cyclonic conditions to 9%, 11.8%, 5.7% and 4.5% for little auks, black-legged kittiwakes, Atlantic puffins and guillemots, respectively [START_REF] Fort | Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic[END_REF][START_REF] Mcknight | Winter dispersal and activity patterns of postbreeding black-legged kittiwakes Rissa tridactyla from Prince William Sound, Alaska[END_REF][START_REF] Shoji | Foraging behaviour of sympatric razorbills and puffins[END_REF][START_REF] Burke | Taking the bite out of winter : Common murres (Uria aalge) push their dive limits to surmount energy constraints[END_REF] . Further, under those conditions, we considered that those species spent respectively, 24%, 18.8%, 16.9% and 16% of the day diving during winter [START_REF] Fort | Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic[END_REF][START_REF] Fort | Energetic consequences of contrasting winter migratory strategies in a sympatric Arctic seabird duet[END_REF][START_REF] Mcknight | Winter dispersal and activity patterns of postbreeding black-legged kittiwakes Rissa tridactyla from Prince William Sound, Alaska[END_REF][START_REF] Dunn | Effects of body size, sex, parental care and moult strategies on auk diving behaviour outside the breeding season[END_REF] . Feather reflectivity was measured with a double beam spectrophotometer (CARY 5000 UV-VIS-NIR, Agilent, USA) with a deuterium-tungstenmercury light source. We used an integrative sphere to measure spectral and diffuse reflectance with a 1 nm resolution across all wavelengths between 300 and 2500 nm. This range covers approximately 98% of the solar spectrum that reaches the Earth's surface.

Reflectance spectra relative to a Spectralon white standard were then computed with the Cary WinUV software. For each species, measurements were made on one ventral and dorsal patch for six individuals. We then calculated the reflectivity of each sample following the methods of Medina et al. [START_REF] Medina | Reflection of near-infrared light confers thermal protection in birds[END_REF] . For each species, the results were averaged across patches. Other morphological properties such as body dimensions were measured on adult bird carcasses of five Atlantic puffins and four black-legged kittiwakes collected on Ré Island (France) during February 2014. All Niche Mapper input data are available in Table S2.

There is limited information about the behavior of seabirds under cyclonic conditions. Yet, we benefited from personal field observations performed by a wide range of North Atlantic seabird experts (e.g., most authors of this publication, as well as Dr. Kyle Elliott and Prof Sarah Wanless, see Table S3). Those led us to assume that the seabird species considered in our study react to winter cyclones by reducing their flight activity to zero when wind speeds exceed 15 m.s -1 (corresponding to cyclones of Class 2, 3 and 4). In surface-feeding blacklegged kittiwakes, we also assumed that conditions experienced, when wind speeds exceed this threshold, precluded them from diving and feeding. Further, for little auks diving in the upper 30 m of the water column [START_REF] Amélineau | Where to forage in the absence of sea ice? Bathymetry as a key factor for an arctic seabird[END_REF] , we assumed that birds are also severely impacted by those cyclonic conditions, as the water here is too perturbed for them to dive and prey on zooplankton. In contrast, deeper diving species such as puffins and guillemots, which can dive down to 75 and 250 m, respectively [START_REF] Burger | Diving depths of Atlantic puffins and common murres[END_REF][START_REF] Chimienti | Taking movement data to new depths: Inferring prey availability and patch profitability from seabird foraging behavior[END_REF] , may still manage to feed [START_REF] Finney | The effect of weather conditions on the feeding behaviour of a diving bird, the common guillemot Uria aalge[END_REF] . Therefore, seabirds were modeled as resting at the surface of water when they did not fly and/or dive. Moreover, flight and diving activities were assumed to remain unchanged under cyclone of Class 1 (for which wind speeds are below 13 m.s -1 , see above).

Using climatic, morphological and behavioral information as stated above, we modeled species-specific, monthly energy requirements for each winter between 2000 and 2016, under four intensities of cyclones and under non-cyclonic conditions. To disentangle the effects of changes in behavior (decreased flight/diving activities) and of weather conditions on bird energy requirements during cyclones, we also calculated those requirements for each species under non-cyclonic conditions, setting behavioral parameters as those displayed during a cyclone with wind speed > 15 m.s -1 .

Estimation of fasting endurance

Fasting endurance was calculated for each species under Class 2, Class 3 and Class 4 cyclonic conditions in the studied area off Newfoundland for each winter months using the method described in [START_REF] Grémillet | Cormorants dive through the Polar night[END_REF] . In this particular context, we assumed that none of the species could feed under cyclonic conditions even if deep divers continued diving. The energy requirement to be supplied was calculated previously using Niche Mapper TM (see above). The amount of energy available was calculated as the masses of lipids and proteins that could be metabolized during a prolonged fast (95% and 25%, respectively [START_REF] Belkhou | Energy contribution of proteins and lipids during prolonged fasting in the rat[END_REF] ), converted into energy (caloric equivalents 39.3 and 18.0•kJ•g -1 , respectively [START_REF] Schmidt-Nielsen | Animal physiology, adaptation and environment[END_REF] ). The body fat and protein contents of each species are indicated in Table S2. Integrating daily body component losses through an iterative procedure, we calculated the maximal duration of fasting that lipid and protein reserves could sustain before one of them was used up. We assumed that lipids and proteins accounted for 75 and 25% of the energy expenditure until 3/4 of lipid reserves were used. They then accounted for 63 and 37%, respectively [START_REF] Belkhou | Energy contribution of proteins and lipids during prolonged fasting in the rat[END_REF][START_REF] Cherel | Relationships between nutrient storage and nutrient utilisation in long-term fasting birds and mammals[END_REF] .

Figure 2 :

 2 Figure 2: Mean cyclone exposure index across the North Atlantic Ocean during winter. See STAR Methods for details on index calculation.

Figure 3 :

 3 Figure 3: Average energy requirements for little auks (A) and Atlantic puffins (B) in the studied area off Newfoundland for each wintering month under cyclonic and non-cyclonic conditions between 2000 and 2016. Error bars were halved for clarity reasons and correspond to standard deviations capturing between-year variation. Results for other species are presented in Data S1G-Data S1K.

  Results of Kruskal-Wallis tests. Comparisons were made between mean energy requirements per conditions tested (Class 1 to 4 cyclones, non-cyclonic conditions with usual seabird flight/diving activities, non-cyclonic conditions with cyclonic seabird flight/diving activities), for each species and each month. Statistical significant results (p<0.05) are indicated in bold. χ2, Chi square; df., degrees of freedom; p, p.value. Outputs of the corresponding Dunn post hoc test are presented in Data S1G-S1K.

  characteristics (sea surface temperature, air temperature and relative humidity), before averaging the values obtained by intensity class for each winter month (see FigureS4) to parameterize the microclimate module of Niche Mapper TM . For each cyclone, we extracted Once we had parameterized the microclimate model of Niche Mapper TM , we parameterized its animal module to obtain seabird daily energy requirements. As this module had already been parameterized to model energy expenditure in little auks, Brünnich's guillemots and common guillemots[START_REF] Fort | Thermodynamic modelling predicts energetic bottleneck for seabirds wintering in the northwest Atlantic[END_REF][START_REF] Fort | Energetic consequences of contrasting winter migratory strategies in a sympatric Arctic seabird duet[END_REF] , we re-used most Niche Mapper TM input values. Missing values and values required to parameterize Niche Mapper TM for black-legged kittiwakes and Atlantic puffins,

	corresponding sea surface temperatures using the NOAA High Resolution SST dataset
	provided	by	the	NOAA/OAR/ESRL	PSL
	(https://psl.noaa.gov/data/gridded/data.noaa.oisst.v2.highres.html#detail) 51 .	The
	corresponding air temperature and relative humidity were extracted from the NCEP/NCAR
	Reanalysis dataset previously used to define cyclone locations (see above). We set the wind
	speed of each cyclone according to its intensity (5-13 m.s -1 = Class 1; 13.1-17 m.s -1 = Class 2;
	17.1-32.5 m.s -1 = Class 3; > 32.6 m.s -1 = Class 4) using the Dvorak classification 13 . We then
	averaged the values obtained by intensity class to calculate mean environmental characteristic
	of each class for each winter month between 2000 and 2016. Finally, for each year, non-
	cyclonic conditions were defined by calculating the daily mean characteristics of each month
	using the same environmental dataset after excluding cyclone days. Wind speeds were
	obtained from the NCEP/NCAR Reanalysis data set. All environmental data used were
	interpolated in a 250 km grid. Mean environmental conditions encountered during cyclonic
	and non-cyclonic events are presented in Figure S4.

Acknowledgements

We warmly thank the many fieldworkers involved in this study. Data collection in Norway, including Svalbard and Jan Mayen, was supported by the Norwegian seabird program SEAPOP (www.seapop.no/en). Thanks to the SEATRACK-program for making tracking data available for the analyzes (http://seatrack.seapop.no/map/). Fieldwork on little auks in Northwest Greenland was funded by the Bureau of Minerals and Petroleum, Greenland Government. The work on the Isle of May was also supported by the Natural Environment Research Council (Award NE/R016429/1 as part of the UK-SCaPE programme delivering National Capability). The New Brunswick Wildlife Trust Fund provided funding for GLS tags on Machias Seal Island. We thank the University of New Brunswick, the Federal Government of Canada, the Government of Greenland and the Danish Ministry of Environment and Food. Thanks to the Polar Continental Shelf Program of Natural Resources Canada (Grant 213-08), and core funding from Environment and Climate Change Canada. Thanks also to the French Polar Institute Paul Emile Victor for funding the ADACLIM program (IPEV program 388 to D. Grémillet et J. Fort) and the ORNITHO-ENDOCRINO program (IPEV program 330 to O. Chastel). We thank Simon Benhamou and Benjamin Robira for their help with BRB-MKDE, Doris Gomez, Christine Andraud and Aurélie Tournié for their valuable help regarding feather reflectivity measurements and Katherine Brownlie for carcass measurements. We thank Kyle Elliott (McGill University, Canada) and Sarah Wanless (Center for Ecology and Hydrology, UK) for their help when assessing the seabird behavior during cyclones and Antoine Chabrolle for our discussion regarding winter wreck phenomena. This is a contribution to the Excellence Chair ECOMM funded by the Region Nouvelle Aquitaine.

Author Contributions

Conceived and designed the project: D.G., J.F, M.C. Software developers and data providers:

Declaration of interests

The authors declare no competing interests.

Quantification and Statistical Analysis

Monthly mean energy requirements per condition tested (Class 1 to 4 cyclones, non-cyclonic conditions with usual seabird flight/diving activities, non-cyclonic conditions with cyclonic seabird flight/diving activities) were compared for each species using a Kruskal-Wallis test (Table 1). When this test was significant (p<0.05), a posthoc Dunn's test was conducted (p values adjusted with the Benjamini-Hochberg method) to conclude on the difference between energy requirements experienced under cyclonic and non-cyclonic conditions (Data S1G-S1K).

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