United States

**Abstract:**

Marine ecosystems are complex, with interconnected natural and anthropogenic drivers influencing spatiotemporal patterns of marine predators. Resource availability is a key factor driving seabird movement and distribution, but information on prey availability is difficult to obtain at useful scales for understanding predator ecology. By using new techniques for estimating prey availability from digital aerial survey data, which capture the location and size of surface-level forage fish shoals, and estimating forage fish occupancy from bottom trawl survey data, we have new methods to describe prey availability for seabirds. This study explores links between seabirds and prey availability by examining Northern Gannets (Morus bassanus) movement in the U.S. Atlantic during the non-breeding season. Using satellite telemetry data from adult and juvenile Northern Gannets (n=75), we employed hidden Markov models to examine behavior states in relation to forage fish availability and environmental covariates. Here, we tested the importance of four types of environmental covariates: static (e.g., depth), dynamic (e.g., sea surface temperature), frontal (e.g., sea surfaced temperature fronts), and behavior-modulating (e.g., wind speed) in Northern Gannet transitions between behavioral states (resident and transiting). Our results suggest that static and dynamic environmental variables played significant roles in movement behavior, with chlorophyll a and depth influencing transitions between resident and transiting states. While frontal features were not as important overall, sea surface temperature fronts specifically played a role in facilitating behavioral transitions. While we expect many of these environmental covariates to be related to forage fish availability, the next step is to use the forage fish occupancy and availability estimates to determine if they improve our understanding of Northern Gannet behavior. Disentangling trophic relationships is critical to understanding the mechanisms driving seabird behavior and space use, particularly in ecosystems that are rapidly changing due to climate and energy development.

**Authors:**

Julia Gulka¹, Evan Adams¹, Alicia Berlin², Kevin Friedland³, Andrew Gilbert¹, Chandra Goetsch¹, William Montevecchi⁴, Matthew Perry², Iain Stenhouse¹, Kate Williams¹

¹Biodiversity Research Institute, ²U.S. Geological Survey, Patuxent Wildlife Research Center, ³National Marine Fisheries Service, ⁴Memorial University

3rd World Seabird Conference

Assessing trophic links, individual movement, and habitat use of non-breeding Northern Gannets

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!

technical paper

**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

Identification and protection of a seabird cafe in the NE Atlantic

**Abstract:**

Although Herring Gull (Larus argentatus) and Lesser Black-backed Gull (L. fuscus) are listed as Birds of Conservation Concern in Ireland, populations are thought to be increasing in urban areas, with associated concerns over the perceived nuisance they pose. Despite this, nothing is known about how individuals use the urban environment in Northern Ireland and how this may differ from their declining coastal counterparts. We used GPS GSM tags to track Herring and Lesser Black-backed Gulls nesting in Belfast during the breeding season to investigate their space-use and identify areas of potential human-gull conflict, providing information to the Northern Ireland Environment Agency and Agri-Food and Biosciences Institute. Comparison was made with Herring Gulls from a nearby natural-nesting population. Time-In-Area and resource selection function analysis showed that roof-nesting gulls of both species predominantly used urban areas, travelling on average 4km from their nests. Individuals showed preferences for foraging in specific areas that were consistent between years, minimising overlap in their space use. In contrast, Herring Gulls from the natural-nesting population travelled further, exploiting agricultural habitats as well as urban areas. Although gulls have the ability to travel large distances to find food, gulls tracked around Belfast did not travel far from their nests and tended to focus their time in urban areas. Our tracking data show that urban areas in Northern Ireland provide safe nesting habitats for gulls and food resources which are used throughout the breeding season, both by roof-nesting individuals and by those from natural-nesting populations. The presence of foraging gulls within the urban environment may be a symptom of poor waste management in certain areas and these are issues that can be addressed to minimise human-gull conflict issues in the future as urban gull populations increase across the island of Ireland.

**Authors:**

Katherine Booth Jones¹, Chris Thaxter¹, Gary Clewley¹, Shane Wolsey¹, Phil Atkinson¹, Niall H. Burton¹

¹British Trust for Ornithology

How GPS tracking and monitoring are informing human-gull conflict issues in Belfast.

**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:**

Arctic terns undertake the longest migration on earth, travelling from their breeding grounds in high latitudes of the northern hemisphere, to the overwintering grounds in Antarctica. This declining species covers distances greater than 90,000 km per year, travels across the planet's vast oceans and encounters more daylight than any other animal. Iceland provides important breeding grounds for arctic terns with 20-30% of the global population returning here annually; during four breeding seasons from 2018 to 2021 we deployed more than 100 biologgers at a large colony. These accelerometers, activity loggers and GPS tracking devices will reveal, with unprecedented accuracy, the flyways used by migrating arctic terns, the locations of key stopover sites, and activities in the Southern Ocean. We will identify the conservation landscape over this epic migration: highlighting areas where human conflict may occur, areas that are protected, and highlight locations that may need protection. The wind conditions that arctic terns encounter will be modelled, and we will determine whether they are using trade winds to aid the migratory flights. Activity loggers will identify how long they spend on the wing, and whether they are foraging on route or flying continuously to known foraging locations. We hypothesise that the migratory routes will be a mixture of those followed by tracked birds from The Netherlands and Greenland. How the routes and behaviours relate to morphology and sex will also be discussed.

**Authors:**

Joanne Morten¹, Julian Burgos², Lee Collins³, Sara Maxwell⁴, Eliza-Jane Morin⁵, Nicole Parr¹, William Thurston⁶, Freydís Vigfúsdóttir⁷, Matthew Witt¹, Lucy Hawkes¹

¹University of Exeter, ²Marine and Freshwater Research Institute, ³N/A, ⁴University of Washington, ⁵University of Westfjords, ⁶Met Office, ⁷University of Iceland

Unravelling the foraging behaviour of the world's longest migrant

**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:**

Tracking individuals on repeated migratory journeys is proving key to understanding the evolutionary forces shaping migratory systems. The extent of between- and within- individual variation in migratory routes, timings, and stopovers of various species has important implications for the understanding of how migratory systems may alter in response to environmental changes. However, this approach has received little attention for seabirds wintering in the tropics, where individuals are often thought to perform less consistent migrations due to the lack of seasonally predictable food resources. Using a 10-year light level geolocator tracking dataset, comprised of 70 individuals with multiple consecutive non-breeding migrations, we will examine the between- and within- individual variation in migratory routes and timings of a tropical seabird, the Round Island petrel. This population of petrels in the Indian Ocean is a three-way hybrid complex consisting of one species from the Atlantic (Pterodroma arminjoniana), two species from the Pacific (P. heraldica and P. neglecta), and inter-specific hybrids. These tracking data reveal extraordinary levels of individual variation in ocean movements, with petrels undertaking non-breeding migrations to different areas across much of the Indian Ocean. Preliminary analysis on a small number of individuals has shown consistent individual differences in the start and end dates of petrel migration, and the routes taken. This, together with the fact that birds can be found breeding on Round Island all year round, means that individuals are potentially exposed to a very wide range of environmental conditions and human-associated impacts, with potentially important consequences for breeding success, survival and, ultimately, the status of this population.

**Authors:**

Kirsty Franklin¹, Ken Norris², Jennifer Gill¹, Norman Ratcliffe³, Simon Butler¹, Nik Cole⁴, Carl Jones⁴, Simeon Lisovski⁵, Kevin Ruhomaun⁶, Vikash Tatayah⁷, Malcolm Nicoll²

¹University of East Anglia, ²Zoological Society of London, ³British Antarctic Survey, ⁴Durrell Wildlife Conservation Trust, ⁵Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, ⁶National Parks and Conservation Service, ⁷Mauritian Wildlife Foundation

Between- and within- individual variation in the migration of a tropical seabird, the Round Island petrel

**Abstract:**

The Arctic Skua Stercorarius parasiticus is the most rapidly declining breeding seabirds species in the UK, with losses of around 82% since the mid-1980s being reported. Typically these species obtain the vast majority of their food via kleptoparasitism of other seabirds around their breeding territories, many of which are also showing losses although not to the same extent. They are also long distance migrants, with ringing recoveries from the UK being reported across the whole extent of the Atlantic. To help provide some insight into the mechanisms underlying these dramatic changes, we instigated a tracking programme to look at foraging behaviour during the breeding season as well as the migration routes and wintering location at two colonies in Scotland - Fair Isle and Rousay. Arctic Skuas from Fair Isle, which have tended to have poor hatching success, were travelling up to 200 km away from the colony during incubation. Long foraging ranges are indicative of low food availability and similar routes were also recorded by target host species in recent years. Whereas birds from Rousay, which usually have had higher breeding success, generally travelled shorter distances during the same period. Birds from Rousay which successfully fledged chicks tended to forage up to 70 km to the north-west of the colony in an area with specific oceanographic features and designated as a Marine Protected Area for larvae Sandeel - a key fish species. Unsuccessful birds tended to forage elsewhere. We will discuss why these differences should arise with respect to possible differences in foraging behaviours between individual birds. There was clear variation in bird's choice of wintering areas with individuals from the same colonies ranging from South America, Southern and Western Africa. Therefore conservation measures for birds in the UK might be best focused around their breeding colonies.

**Authors:**

Liz Humphreys¹, Sarah Harris², Helen Aiton¹, David Aiton¹, Chris Thaxter², Dawn Balmer², Calladine John¹

¹British Trust for Ornithology, Scotland, ²British Trust for Ornithology

Year round movements of the Arctic Skua - understanding drivers of change in a declining species

**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

Assessing trophic links, individual movement, and habitat use of non-breeding Northern Gannets

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Assessing trophic links, individual movement, and habitat use of non-breeding Northern Gannets

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Identification and protection of a seabird cafe in the NE Atlantic

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Development and delivery of a citizen science seabirds at sea monitoring programme

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