United States

**Abstract:**

Seabirds are one of the most threatened groups of birds globally, and many seabird populations are experiencing severe declines. This is true in the Atlantic ocean where many seabird populations have undergone widespread breeding failures, highlighting the need for conservation action in this region. Identifying sites suitable for protection is one approach for seabird conservation. While breeding colonies are generally well protected across European countries, there remains a gap for important non-breeding and foraging sites. We analysed all available seabird tracking data for the Northeast Atlantic (www.seabirdtracking.org). This totaled 2,188 tracked individuals from 23 species, from 105 colonies across 11 countries in both the North and South Atlantic. We followed standardized methods of identifying marine hotspots based on tracking data and information on population abundance, in collaboration with more than 60 from researchers and data holders. We identified a seabird diversity and abundance hotspot in the middle of the North Atlantic, which was previously unknown. This area is an important pelagic foraging ground for at least 22 seabird species, including 7 globally or regionally threatened species. The area is particular important for migratory seabird species, with the highest concentrations occurring during the winter period (October-March) with up to 5 million individuals using the area. The spring summer period (April-September) saw the highest number of species using the area (n=21) and also saw large numbers of birds (up to 3.3 million), many as a stopover during trans-equatorial migrations. Protection of this &#39;seabird cafe&#39; comes under the remit of the Regional Seas Convention for the North East Atlantic (OSPAR), who are considering the site as a marine protected area. Protection of this site would require collaboration between all OSPAR parties, as well as competent authorities operating in the region.

**Authors:**

Tammy Davies¹, Ana Carneiro¹, Maria Dias¹

¹BirdLife International

3rd World Seabird Conference

Identification and protection of a seabird cafe in the NE Atlantic

Welcome Seabirders!  

Welcome to Virtual World Seabird Conference 3 - vWSC3! Whether you are in your office or lab, at home, in a coffee shop or bar poaching some wifi, or at a remote field site or research vessel – we are very excited to welcome you to the third ever World Seabird Conference. 

We would like to thank ALL of you for being so patient as WSC3 was scheduled, postponed, rescheduled, revised to virtual, and scheduled again. Throughout all those iterations there was one message that remained perfectly clear – seabirders were eager to meet and share their science. If we could not meet in person then virtual it would have to be, but a 3rd WSC was something everyone wanted. That support and commitment helped the WSU Board of Directors and Member Societies sort through all of the challenges they faced to plan and hold this conference. 

The list of those that need to be thanked is long and, while we plan on recognizing many during the live closing plenary, it is important to do so here in writing as well. 

The Australasian Seabird Group was our Local Host for our plan to meet in Hobart, Tasmania. They invested substantial time and effort to find venues and plan events that we unfortunately were not able to visit. Nonetheless we appreciate their work on behalf of WSC3 and encourage all of you to thank them when you see their members in Gathertown or elsewhere during our virtual meeting. Their willingness to host created the initial excitement for WSC3 and without that our vWSC would not have been possible.

We also wish to thank the Science Program Committee, the Virtual Committee, and the Early Career Scientist Committee for their hard work planning the logistics, events, and schedule for vWSC3. These committees also had to deal with changing parameters and short timelines that made what is always a challenging task even more challenging. The Travel Awards Committee also invested time and effort in developing procedures for awarding travel funds that ultimately would not be implemented. 

Our ability to shift from an in-person to a virtual meeting, and to do so in a way that would be financially feasible, was due to the effective efforts of The International Fundraising Committee and to our financial sponsors. The IFC raised funds to support WSC3 and then, through the good relationships they built with sponsors, ensured we could re-envision how those funds could be used to support a virtual conference that would be affordable and high-quality.

We all owe the WSU Board of Directors and the Representatives of the Member Societies a great deal of thanks. They are the ones who manage the WSU and, for the past 18 months, have had to have a series of challenging meetings and conversations, have had to make a series of difficult choices, have had to do all of that while considering the short- and long-term health of WSU and the World Seabird Conferences, and did this while also managing their own challenges at their day jobs. We are grateful for their diligence, patience, foresight, and throughout all of the meetings, their collegiality. Also – a 6-year term is quite a commitment!

There would not be a WSC3 without a successful WSC1 and WSC2. Thanks go to the Pacific Seabird Group for their support of WSC1 in Victoria, Canada, and to the African Seabird Group for their support of WSC2 in Cape Town, South Africa. In each of these endeavors and for our current conference we were fortunate to work with a dependable and trustworthy partner in Podium Conferences. Michelle Smith and Marischal de Armond have become valued members of our team and have not only helped us plan conferences but have assisted and advised the WSU Chairs and Board on issues above and beyond conference planning. 

As we embark on our vWSC3 week we extend to all of you our thanks for showing up, for being patient, and most importantly for the work you do with seabirds. We are all part of a unique, global community that shares an interest, a fascination, and a passion for birds that make a living in our world’s oceans. We have advanced the science, conservation, and management of seabirds as well the ecosystems they inhabit. We are consistently impressed and motivated by the work you do. 

The WSU formed in 2010 because we saw the need for a global organization to address challenges at a global level. Over the past 11 years WSU has grown, adapted, and evolved to become the community that this week is making vWSC3 a reality. Enjoy the week, appreciate and support the friends and colleagues you have made in the community, and if you see us in a virtual hallway please stop and say hello! 

Thank you for the opportunity to serve all of you and the WSU over the past few years,

Nicholas Carlile, Interim Chair, WSU<br>
Patrick Jodice, 2nd Chair of the WSU<br><br>

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Join us for four days of science, networking and virtual engagement with delegates from around the world!

**Abstract:**

Seabirds are one of the most threatened groups of birds globally, and many seabird populations are experiencing severe declines. This is true in the Atlantic ocean where many seabird populations have undergone widespread breeding failures, highlighting the need for conservation action in this region. Identifying sites suitable for protection is one approach for seabird conservation. While breeding colonies are generally well protected across European countries, there remains a gap for important non-breeding and foraging sites. We analysed all available seabird tracking data for the Northeast Atlantic (www.seabirdtracking.org). This totaled 2,188 tracked individuals from 23 species, from 105 colonies across 11 countries in both the North and South Atlantic. We followed standardized methods of identifying marine hotspots based on tracking data and information on population abundance, in collaboration with more than 60 from researchers and data holders. We identified a seabird diversity and abundance hotspot in the middle of the North Atlantic, which was previously unknown. This area is an important pelagic foraging ground for at least 22 seabird species, including 7 globally or regionally threatened species. The area is particular important for migratory seabird species, with the highest concentrations occurring during the winter period (October-March) with up to 5 million individuals using the area. The spring summer period (April-September) saw the highest number of species using the area (n=21) and also saw large numbers of birds (up to 3.3 million), many as a stopover during trans-equatorial migrations. Protection of this 'seabird cafe' comes under the remit of the Regional Seas Convention for the North East Atlantic (OSPAR), who are considering the site as a marine protected area. Protection of this site would require collaboration between all OSPAR parties, as well as competent authorities operating in the region.

**Authors:**

Tammy Davies¹, Ana Carneiro¹, Maria Dias¹

¹BirdLife International

technical paper

**Abstract:**

With expanding marine urbanisation, the introduction of man-made structures into our seas, a broader perspective on their ecological implications is timely to predict seabird responses to environmental change. Understanding the physical mechanisms characterizing seabird foraging sites can help predict how they may respond to altered hydrodynamics due to offshore structures. For instance, physical processes such as vertical mixing and sediment dynamics can be strongly modified through the introduction of anthropogenic installations into tidal seas. They can also lead to the generation of turbulent coherent structures such as complex three-dimensional wakes (von Kármán vortex streets). Similar to oceanic mesoscale features (e.g. fronts and eddies), small-scale features including shear lines, vortices and local upwellings can provide physical mechanisms to change prey vertical distribution and accessibility to surface foragers. We present some recent work showing that the wake of a surface-piercing tidal energy monopile in the UK promoted a localised and persistent foraging hotspot for terns (Sternidae), with numbers greatly exceeding counts at adjacent natural wake sites. The number of foraging terns was strongly coupled to peak flood tides, where strong vertical mixing within the wake, visualized using acoustic backscatter profiles, may have acted like a prey conveyor belt. We also summarise the physical characteristics from other tidally-driven foraging sites, including shallow upwellings. Tracked by hovering drones using machine learning, tern foraging was highly localised. Through analysis of individual flight trajectories, we can now extract track characteristics to provide more detailed information on e.g. flight speed and tortuosity to investigate foraging behaviour. For this, we also use the drone imagery to map the underlying surface velocity field using particle image velocimetry techniques, thereby capturing evolution of the highly dynamic physical features (vorticity, upwelling, downwelling). This novel approach enables investigation of associations between foraging behaviour and highly localised, dynamic flow features at each timestep to understand the ecological importance of hydrodynamic forcing.

**Authors:**

Lilian Lieber¹, Alex Nimmo-Smith²

¹Queen's University Belfast, ²The University of Plymouth

Understanding the association of localised seabird foraging and physical dynamics to help predict responses to environmental change

**Abstract:**

Breeding failure is expected to induce behavioural changes in central place foraging seabirds. Indeed, failed breeders do not have to regularly come back to their colony for reproductive duties and thus, they are not constrained anymore in their movements for the rest of the breeding season. Accordingly, they are expected to adjust their at-sea behaviour, travelling longer in distance and/or time to reach foraging grounds. They are also expected to use different foraging areas to decrease local intra-specific competition with successful breeders. However, so far, only few studies have investigated the effect of breeding failure on individual behaviour and distribution. In this study, we compared the at-sea behaviour and habitat use of successful and failed Indian yellow-nosed albatrosses nesting in Amsterdam Island, Southern Indian Ocean, during two chick-rearing periods. Failed breeders exhibited the same at-sea foraging behaviour, travelling as far and as long as successful breeders. They also spent the same amount of time on their nest between at-sea trips. Nevertheless, habitat models revealed a partial spatial segregation of failed breeders, which used specific foraging areas characterized by deeper and colder waters, in addition to the ones they shared with successful breeders. Our study stresses the importance of considering breeding failure when aiming at understanding the spatial distribution of individuals, especially in a conservation perspective.

**Authors:**

Aurore Ponchon¹, Amandine Gamble², Inkeri Ahtiainen¹, Jeremy Tornos³, Karine Delord⁴, Christophe Barbraud⁴, Justin Travis¹, Henri Weimerskirch⁴, Thierry Boulinier⁵

¹University of Aberdeen, ²University of California Los Angeles, ³CEFE-CNRS UMR 5175, ⁴CEBC-UMR 7372, ⁵CEFE-CNRS-UMR5175

Similar foraging behaviour but different habitat use between failed and successful breeding albatrosses

**Abstract:**

Top predators, such as seabirds, integrate information over multiple temporal and spatial scales, as well as trophic levels. Marine communities have changed greatly over the past century due to industrial fisheries, climate change and marine pollution. Here, we examine whether the fingerprint of such change can be observed in seabird eggs collected from Pacific Canada between 1968 and 2017. We examined a suite of six species of seabirds (Ancient Murrelet, Double Crested Cormorant, Leach's Storm Petrel, Great Blue Heron, Rhinoceros Auklet, Pelagic Cormorant) that inhabit the southern coast of British Columbia and vary in their habitat from the inshore to offshore. The six species overlapped considerably within a δ15N-δ13C biplot, but a multivariate analysis showed that amino acid-specific standard ellipses showed little overlap. Thus, each of the six species occupied their own isotopic hypervolumes (niches), but this was only apparent when considering more complex dietary indices than those available from bulk δ15N and δ13C alone. These hypervolumes did not change for five species, but showed a substantial shift in double-crested cormorants. For cormorants, there was a shift from pelagic to benthic prey consistent with a decline due to overfishing of Pacific herring. Thus, the diet of five species of seabirds was relatively constant over time, reducing niche overlap, but the species at the highest trophic level showed a marked change in diet in response to fisheries.

**Authors:**

Francis van Oordt¹, Kyle Elliott¹

¹McGill University

Changing diet in seabirds from Pacific Canada over 50 years: evidence from amino acid-specific stable isotope analysis

**Abstract:**

Understanding how populations within a species can vary their response to seasonal stressors across spatial and temporal scales provides insight into the adaptability of that species. One species where such information is desired is the red throated diver (RTD, Gavia stellata), whose non-breeding season ecology is relatively unknown. RTDs are also predicted to be facing ever-increasing pressures from anthropogenic activity, making improving our understanding of this species all the more imperative. Physiological and behavioural models allow such a fundamental understanding of the ecology of a species. Here we used a combination of Light-based Geolocator and Time-depth Recorder devices to reveal non-breeding location and behavioural time budgets for RTDs from three different populations: Iceland, Scotland and Finland. Using allometric scaling equations and the knowledge gained from the behaviour budgets, we constructed models to estimate the energy expenditure of RTDs for the first four months of the non-breeding period. Our results show differing migration strategies across the three populations, with populations being migratory, partially migratory and resident. We found that both behaviour budgets and energy expenditure varied spatially and temporally, with migratory populations showing the largest degree of temporal change in their behaviour budget. We also found that energy expended on thermoregulation varied across the sites and that populations were able to overcome this additional stressor through physiological and behavioural adaptions. Our study answers several important questions about RTD behaviour and energetics, as well as more broadly providing examples of divergent non-breeding season survival tactics across spatial scales. This new information will enable us to carry out further work to examine how constrained RTDs are and their ability to adapt to increased anthropogenic pressure.

**Authors:**

James Duckworth¹, Sue O'Brien², Ib Petersen³, Francis Daunt⁴, Aevar Petersen⁵, Logan Johnson⁵, Petteri Lehikoinen⁶, David Okill⁵, Roni Väisänen⁷, Jim Williams⁵, Stuart Williams⁵, Jonathan Green¹

¹University Of Liverpool, ²Joint Nature Conservation Committee, ³Aarhus University, ⁴UK Centre for Ecology & Hydrology, ⁵Independent, ⁶Avescapes, ⁷Aevscapes

Non-breeding behaviour and energy expenditure of red-throated divers (Gavia stellata)

**Abstract:**

Many seabird populations are rapidly declining. For numerous colonies, only recent and/or sparse monitoring data are available that do not consider the population's long-term variability when developing management strategies. In our study, we used a broad spectrum of landscape-scale paleoenvironmental approaches on dated lake sediment cores to examine millennial-scale dynamics from two of the world's largest colonies of vulnerable Leach's Storm-petrel (Hydrobates leucorhous) on Baccalieu Island and Grand Colombier Island, both located off the coast of Newfoundland, Canada. Available survey data demonstrates the storm-petrel colonies have declined since the 1980s, and may have stabilized by the early 2000s. However, little is known about the timing and cause of the colony declines, nor is there information on the natural long-term variability prior to the influence of anthropogenic stressors. Our reconstructed populations, based on limnological changes from seabird-derived nutrient and metal inputs preserved in sediments, corroborate the limited survey data that suggest a recent decline, and indicate large-scale fluctuations over millennial timescales. On Baccalieu Island, two distinct colony peaks were observed during the last 1,700 years, and on Grand Colombier Island we track at least four distinct peaks over 5,500 years. The asynchronous peaks and valleys in population size of the studied colonies, coupled with in-field observations and genetic analyses, provide evidence for recruitment and mobility of storm-petrels among colonies as key dynamics in the storm-petrel metapopulation. Based on our results, we emphasize that the recent decline in storm-petrels is real and requires immediate conservation action to understand the mechanism(s) driving the decline. Our long-term perspectives highlight the need for protected area networks to sustain natural population cycles. We demonstrate paleolimnological techniques have the potential to provide a long-term context for the size and persistence of seabird populations, which can lead to more realistic conservation strategies that take into account temporal demographic dynamics across a species' range.

**Authors:**

Matthew Duda¹, Gregory Robertson², Joeline Lim¹, Jennifer Kissinger³, David Eickmeyer³, Christopher Grooms¹, William Montevecchi⁴, Linda Kimpe³, Neal Michelutti¹, Jules Blais³, John Smol¹

¹Queen's University, ²Environment and Climate Change Canada, ³University of Ottawa, ⁴Memorial University of Newfoundland

Assessing millennial-scale changes in seabird colony size using paleoenvironmental techniques: Case studies of Leach's Storm-Petrels in Eastern North America

**Abstract:**

What are the forthcoming climate change impacts on the seabird community wintering in the North Atlantic? This is the question we addressed for five key species which represent 75% of all seabirds breeding in the North Atlantic (Alle alle, Fratercula arctica, Uria aalge, Uria lomvia and Rissa tridactyla), based on a multi-colony study. Specifically, we compiled tracking data for >1400 birds from 39 breeding colonies, to map their wintering distribution in the North Atlantic. We then modelled their energy requirements using NicheMapperTM, a mechanistic model which simulates heat exchanges between bird bodies and their surroundings based on species-specific morphological, physiological and behavioral characteristics. Further, we modelled seabird prey fields across the North Atlantic in winter, using Dynamic Bioclimate Envelope Models parametrized according to the methods of the Nereus Program. Information on seabird energy requirements and energy available through their prey were then merged using Resource Selection Functions, to obtain multi-species wintering energyscapes. Finally, we used HadGEM2-ES outputs for two climatic scenarios (RCP 2.6 and RCP 8.5) and two periods (2045-2055 and 2090-2100) to simulate future energyscapes for each species/colony, and to predict future winter distributions. Through this multidisciplinary approach using biologging, remote sensing, online databases and an array of modelling tools, we demonstrate how the North Atlantic seabird community may optimize its winter distribution under the influence of global warming. Notably, we speculate that a series of high-latitude species might become year-round Arctic residents in the near future. Our analyses illustrate how global warming may impact the biogeography of migratory species at multi-colony and community levels, and how seascape conservation and marine management should integrate these upcoming major changes.

**Authors:**

Manon Clairbaux¹, Jérôme Fort², Warren Porter³, Paul Mathewson³, William Cheung⁴, Hallvard Strøm⁵, Borge Møe⁶, Per Fauchald⁶, Sébastien Descamps⁷, Hálfdán Helgason⁷, Vegard Bråthen⁶, Benjamin Merkel⁷, Tycho Anker-Nilssen⁶, Ingar Bringsvor⁸, Olivier Chastel⁹, Signe Christensen-Dalsgaard⁶, Johannis Danielsen¹⁰, Francis Daunt¹¹, Nina Dehnhard⁶, Kjell Einar Erikstad⁶, Alexey Ezhov¹², Maria Gavrilo¹³, Yuri Krasnov¹², Magdalene Langset⁶, Svein Lorentsen⁶, Bergur Olsen¹⁴, Tone Reiersten⁶, Geir Systad⁶, Þorkel Þórarinsson¹⁵, Mark Baran¹⁶, Anthony Diamond¹⁶, Annette Fayet¹⁷, Michelle Fitzsimmons¹⁸, Morten Frederiksen¹⁹, H.Grant Gilchrist²⁰, Tim Guilford¹⁷, Nicholas Huffeldt¹⁹, Mark Jessopp¹, Kasper Johansen¹⁹, Amy-Lee Kouwenberg¹⁸, Jannie Linnebjerg¹⁹, Laura McFarlane Tranquilla²¹, Mark Mallory²², Flemming Merkel¹⁹, William Montevecchi¹⁸, Anders Mosbech¹⁹, Aevar Petersen²³, David Grémillet²⁴

¹University College Cork, ²LIENSs CNRS, ³University of Wisconsin-Madison, ⁴Canada Research Chair and the University of British Columbia, ⁵Norwegian Polar Institute, ⁶Norwegian Institute for Nature Research, ⁷Norwegian Polar Institute, ⁸BirdLife Norway, ⁹CEBC-CNRS, ¹⁰University of the Faroe Islands, ¹¹CEH, ¹²MMBI, ¹³Association Maritime Heritage, ¹⁴Faroe Marine Research Institute, ¹⁵Northeast Iceland Nature Research Centre, ¹⁶University of New Brunswick, ¹⁷University of Oxford, ¹⁸Memorial University of Newfoundland, ¹⁹Århus University, ²⁰Wildlife Research Division, Environment and Climate Change Canada, National Wildlife Research Centre, ²¹Bird Studies Canada, ²²Acadia University, ²³Icelandic Institute of Natural History, ²⁴CEFE CNRS

Climate change impacts on multi-species seabird wintering hotspots in the North Atlantic - An energyscape approach

**Abstract:**

The recent development of global databases to store data has facilitated the share of information between researchers. The field of marine conservation has been one of the most noticeable beneficiaries of such collaborations. Only now, with these multi-colony datasets that encompass numerous species and sometimes taxa (e.g. seabirds and marine mammals), are researchers able to understand the "big picture" of the importance of different marine areas, and build stronger cases to support and advocate for their effective protection. In this talk we show several examples of how the Seabird Tracking Database held By BirdLife International has been used to promote seabird conservation based on multi-colony analyses. We will give a particular focus on studies involving a large number of collaborators and that resulted in a practical conservation outcome, such as 1) the identification of a hotspot for 23 migratory species (from 105 colonies) in the North-East Atlantic, which resulted in an MPA proposal in the OSPAR convention area; 2) the identification of areas of high bycatch risk for albatrosses and petrels in the southern ocean, based on data from 36 colonies and used to inform Regional Fisheries Management Organizations on bycatch mitigation measures; and 3) the identification of Key Biodiversity Areas for the community of 10 seabird species breeding in multiple colonies at South Georgia and the South Sandwich Islands (SGSSI), where results were used to evaluate the role of the SGSSIMPA in covering the most important sites for the conservation of top marine predators breeding at this archipelago. This presentation will be focused on the challenges faced in collating data for a large number of species, the statistical methods to deal with different types of data and on the discussion of the existing conservation gaps that can be addressed with similar approaches.

**Authors:**

Maria Dias¹, Ana Carneiro¹, Tammy Davies¹, Jonathan Handley¹, Elizabeth Pearmain¹

¹BirdLife International

The importance of multi-colony and multi-species studies for seabird conservation

**Abstract:**

Understanding marine predator distributions is essential if we hope to arrest their catastrophic declines. In temperate and polar seas, predictable oceanographic features create productive hotspots and predator aggregations, which are suitable for designation as protected areas. In the tropics, however, oligotrophic conditions and weaker seasonal cues limit the tendency of marine predators to form lasting concentrations and thereby impede our ability to identify important at-sea areas. Here, we track the non-breeding movements of an assemblage of tropical seabirds (n = 365 individuals, from 10 species and 10 colonies) from across the Western Indian Ocean. These species dispersed widely during non-breeding, covering the entire tropical Indian Ocean, and spent no extended periods of residency in concentrated areas. Habitat selection models revealed divergent species-specific responses to a suite of environmental parameters. This in turn created even species richness with no clear hotspots, either when considering observed tracking data or extended to predicted distributions from colonies across species entire Indian Ocean range. When evaluating the marine protected area network in the region, areas of high species richness were not well captured by MPAs, even if predicted to be fully protected. Dispersive non-breeding movements of tropical seabirds in the Western Indian Ocean are in stark contrast to widespread patterns of biodiversity hotspots at higher latitudes and suggest that at-sea conservation of tropical marine predators requires re-consideration of traditional, spatial methods. This is crucial given the long-term erosion of tropical seabird assemblages but encouraging strides towards the conservation and restoration of colonies on land.

**Authors:**

Alice Trevail¹, Malcolm Nicoll², Robin Freeman², Matthieu Le Corre³, Jill Schwarz⁴, Pierre-Andre Adam⁵, Vincent Bretagnolle⁶, Licia Calabrese⁷, Chris Feare⁸, Audrey Jaeger³, Carl Jones⁹, Camille Lebarbenchon³, Ken Norris², Sabine Orlowski³, Patrick Pinet¹⁰, Virginie Plot³, Norman Rattcliffe¹¹, Gerard Rocamora¹², Nirmal Shah¹³, Stephen Votier¹⁴

¹University of Exeter, ²The Zoological Society of London, ³Université de la Réunion, ⁴University of Plymouth, ⁵Island Conservation Society, ⁶Centre d'Etudes Biologiques de Chize (CEBC-CNRS), ⁷Independent Researcher, ⁸WildWings Bird Management, ⁹Durrell Wildlife Conservation Trust, ¹⁰Parc national de La Réunion, ¹¹British Antarctic Survey, ¹²University of Seychelles, ¹³Nature Seychelles, ¹⁴Heriot-Watt University

Diffuse patterns of at-sea movements by tropical seabirds

**Abstract:**

Species distributions are shifting poleward in response to climate change, but not all with the same pace or pattern. In particular, colonial predators may struggle to keep pace with prey because colony formation is rare. Despite its importance, little is known about the complex process of range shifting in colonial animals. Seabirds provide a useful model, as they are tied to land in the breeding season, but their marine prey is not. Existing colonies provide defence, mates and information, but also cause intense competition for food, which is reflected in high foraging effort as individuals must travel further and search for longer. As such, smaller colonies can expand more quickly than larger colonies, particularly if nearby foraging grounds attract recruits. The presence of nearby colonies also increases foraging effort due to competition, suggesting a possible benefit to being at range margins. Here we examine foraging trip duration and range, using data obtained from bird-borne loggers, to quantify effort across a large latitudinal gradient (48.15°N to 71.23°N) in the northern gannet Morus bassanus. This wide-ranging marine predator provides a rare example of a well-documented poleward-shifting seabird. We collated data representing 850 breeding gannets from 20 of the 54 currently occupied colonies. Trip duration and range both increased substantially with colony size. However, after controlling for colony size, trip duration and range also decreased significantly with latitude suggesting suitable conditions for gannets on the northern edge of their range but poor conditions at the southern edge. Lower foraging effort at the expanding range margin may allow distribution shift in colonial species in response to environmental change if the barriers to colony formation can be overcome.

**Authors:**

Bethany Clark¹, Freydís Vigfúsdóttir², Sarah Wanless³, Keith Hamer⁴, Thomas Bodey⁵, Jez Blackburn⁶, Sam Cox⁷, Stefan Garthe⁸, David Grémillet⁹, Amélie Lescroël¹⁰, William Montevecchi¹¹, Pascal Provost¹², Ewan Wakefield¹³, Stephen Votier⁵

¹BirdLife International, ²University of Iceland, ³Centre for Ecology and Hydrology, ⁴University of Leeds, ⁵University of Exeter, ⁶British Trust for Ornithology, ⁷Centre d'Etude Biologique de Chizé, ⁸Kiel University, ⁹University of Montpellier, ¹⁰Point Blue, ¹¹Memorial University of Newfoundland, ¹²Ligue pour la Protection des Oiseaux, ¹³University of Glasgow

Reduced foraging effort at the expanding range margin could facilitate poleward shift in a colonial seabird, the Northern gannet Morus bassanus

**Abstract:**

Understanding the migratory patterns of seabirds is vital to developing integrated conservation strategies that account for demographic processes and sources of risk throughout the annual cycle. As year-round residents throughout their coastal marine breeding and wintering ranges, Brown Pelicans (Pelecanus occidentalis) have historically been considered non-migratory. Over the past ten years, however, year-round GPS tracking of pelicans captured at multiple breeding colonies across their eastern North American range has revealed complex variation in migratory patterns and propensity among individuals, colonies, and geographic regions. This presentation will synthesize data gained from several large-scale, multi-colony telemetry studies to examine how individual characteristics, intraspecific interactions, and environmental variation interact to drive migratory patterns in this unique nearshore seabird species. Using network analyses and risk modeling, we will further assess the potential consequences of migratory heterogeneity for key ecological and demographic processes, including metapopulation structure, individual interactions, and risk exposure. Our results advance ecological understanding of partial migration, as well as identifying locations and periods of elevated vulnerability as targets for conservation and restoration action.

**Authors:**

Juliet Lamb¹, Yvan Satge², Caroline Poli³, Bradley Wilkinson², Autumn-Lynn Harrison⁴, Patrick Jodice⁵

¹University of Rhode Island, ²Clemson University, ³University of Florida, ⁴Smithsonian Conservation Biology Institute, ⁵U.S. Geological Survey

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