United States

**Abstract:**

Increasingly in seabird research, individual differences in life history traits are being described within populations of both pelagic and nearshore species. Among these traits is partial migration, whereby some individuals relocate from the breeding grounds on a seasonal basis while others remain sedentary year-round. Importantly, as described by obligate partial migration, individuals can alternate between sedentary and migratory strategies on an interannual basis. Despite the relatively widespread incidence of partial migration in avian species, mechanistic causes underlying this behavior remain poorly understood, especially in tropical and subtropical systems. We evaluated three competing hypotheses driving partial migration in brown pelicans (Pelecanus occidentalis) tracked with GPS transmitters in the South Atlantic Bight, USA. These include (1) competitive release (i.e., intraspecific competition for limited resources drives migration of subordinates), (2) fasting endurance (i.e., individuals unable to meet energetic demands will migrate), and (3) thermal tolerance (i.e., migratory probability is directly influenced by thermal extremes). We evaluated these hypotheses in relation to intrinsic factors such as sex, body condition, and reproductive status and extrinsic factors such as environment, climate, and a measure of anthropogenic food subsidy. While prior evidence suggests that pelican migration in other parts of their global range (e.g. Gulf of Mexico) is influenced by density dependence, we highlight differences in colony sizes, behavior, and coastal geomorphology in the South Atlantic Bight that play a role in determining migratory probability for this region. We subsequently modeled how migration probability may change under various climate change scenarios along with concomitant changes in non-breeding distribution, and underscore the need to examine drivers of animal movement throughout the range of a given species.

**Authors:**

Bradley Wilkinson¹, Patrick Jodice²

¹Clemson University, ²USGS South Carolina Cooperative Fish and Wildlife Research Unit

3rd World Seabird Conference

Brown pelicans as a model of partial migration in nearshore seabirds

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!

poster

**Abstract:**

While the problem of plastic pollution in the oceans has received wide media and public attention in the last decade, the scientific basis for our knowledge of its effects and consequences is still limited, despite meeting the irreversibility and global ubiquity criteria of being a planetary boundary threat. Since 2005, the Adrift Lab has studied the impact of plastics pollution on shearwaters (Ardenna spp) in Australia with an aim to understand the nature, extent, and consequences of plastics for the birds and their island ecosystems. We have employed a variety of tools, including contaminant analysis, nutritional biochemistry, histology, and blood chemistry combined with annual surveys of the frequency and intensity of plastic pollution, focusing on Flesh-footed Shearwaters (Ardenna carneipes) on Lord Howe Island. Here, we review the progress in knowledge around how plastics may be affecting individuals, populations, and communities. Birds with more plastics tend to have slower growth rates, higher contaminant burdens, altered physiology, and show tissue damage to the gastrointestinal tract compared with less-affected individuals. Birds also transport considerable volumes of plastic to the island and deposit it through regurgitation, and decomposition of carcasses. As one of the longest-running plastics monitoring research programmes in the world, we are able demonstrate the annual variability in plastic ingestion, and leverage this knowledge to begin to explore the broader effects of plastics on marine wildlife.

**Authors:**

Alexander Bond¹, Jennifer Lavers², Ian Hutton³

¹Natural History Museum, ²University of Tasmania, ³Lord Howe Island Museum

The shearwater and the bottlecap: understanding the broader impacts of plastic ingestion on seabirds

**Abstract:**

Plastic circulates at sea threatening marine megafauna. Southern Giant Petrels (SGP, Macronectes giganteus) are known to consume plastic, but the source and accumulation areas of marine litter remain unknown. The goal of this study is to understand how foraging behavior of SGP will impact their risk of plastic ingestion by mimicking the circulation of floating debris. We tracked 34 adult and juvenile birds using either PTTs or GPS, from Arce (45°00'S; 65°29'W) and Gran Robredo Islands (45°80'S; 66°03'W). To mimic plastic circulation at sea we employed the output of 15 years of daily-forcing simulations using ROMS-Agrif. We designed lagrangian simulations of particles (individual based model) using off-line particle-tracking model. Simulations incorporate physical characteristics of plastic that reaches the area from coastal cities and ships. Dual foraging strategy was recorded for all breeding birds. During short trips (N=108, recorded with GPS), both sexes foraged at 38.5 ± 12.9 km from the colony. During long trips (N= 60), males mainly foraged along the coast at 382 ± 65 km from the colony, while females moved to the shelf break and the middle shelf (459 ± 58 km). Throughout austral fall and winter, adults remained on the Patagonian shelf, but juveniles moved north using the shelf break as a corridor. The drift model showed how simulated particles generated a plastic corridor along the Patagonian shelf until reaching the Malvinas-Brazil confluence, concurring with juveniles' migration path. Accumulation hot spots occurred in the mid shelf and along the shelf break with a strong seasonal variation, overlapping with breeding females. Litter coming from cities and fisheries accumulated near the colony, corresponding with adult foraging areas during short trips, which may explain the 50 to 73% of plastic items found in chicks' diet. Our results showed that marine litter dispersed by ocean circulation, will threat SGP, depending on sex, age class, and breeding stage. Understanding where marine organisms come into contact with plastic, could help elucidate negative effects at population-levels to design management strategies that mitigate this environmental issue.

**Authors:**

Gabriela Blanco¹, Mariano Tonini², Gallo Luciana¹, Flavio Quintana¹

¹Instituto de Biologia de Organismos Marinos - CONICET, ²Instituto Andino Patagonico de Tecnologias Biologicas y Geoambientales - CONICET

Sex, age class, and foraging strategy of the Southern Giant Petrel might influence the hazard of plastic ingestion on the Patagonian shelf

**Abstract:**

Bycatch of seabirds in longline fisheries includes mortalities (during setting) and live captures (mainly during hauling). The proportion of injured live-caught birds that later die is unknown, complicating efforts to quantify impacts of fisheries, particularly as live-capture rates will probably increase with vessels adopting night setting as a mitigation measure. Over a 26-year period at South Georgia, foul-hooking indices - birds with embedded hooks or entangled among 10 000s checked at the colony - were broadly similar in wandering albatrosses and giant petrels, an order of magnitude lower in black-browed albatrosses and nil in grey-headed and light-mantled albatrosses. This likely reflected differing degrees of overlap with fisheries and interaction with gear during hauling. Indices peaked in the early 2000s, then declined, broadly corresponding with changing fishing practices - the lagged effect of a seasonal fisheries-closure, introduction of a new fishing system, reduced effort in some demersal fisheries, general improvements in bycatch mitigation - indicating that foul-hooking indices at colonies can reflect relative risk for different species over time, and be a useful adjunct to vessel-based monitoring of live-capture rates. Taking into account age and status when reported, and annual survival probabilities in the wider population, subsequent survival of live-caught and released wandering albatrosses was around 40% of that expected for the wider population. This has major implications for ecological risk assessments that seek to determine the impacts of fisheries on seabirds, as most do not currently consider deleterious impacts of live capture.

**Authors:**

Richard Phillips¹, Andrew Wood¹

¹British Antarctic Survey

Variation in live-capture rates of albatrosses and petrels in fisheries, post-release survival and implications for monitoring and management

**Abstract:**

Plastic pollution ingestion by seabirds is an increasing environmental problem even in remote areas such as the Arctic, yet knowledge on plastic pollution ingestion by several Arctic seabirds is limited, making it difficult to assess trends. We examined plastic pollution ingestion by northern fulmars (Fulmarus glacialis), black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia) and black guillemots (Cepphus grylle) in the Canadian Arctic to assess species-specific and temporal differences in plastic ingestion over ten years. Seventy-two percent of fulmars and 15% of kittiwakes ingested plastic, while guillemots and murres did not. The number and mass of plastic ingested by fulmars decreased between the two periods (2008 and 2018), but the frequency of occurrence of plastic ingestion did not change, although sample sizes were less than ideal. Future research with larger samples is recommended to reinforce these trends in plastic ingestion by Arctic seabirds.

**Authors:**

Julia Baak¹, Jennifer Provencher², Mark Mallory³

¹McGill University, ²Environment and Climate Change Canada, ³Acadia University

Plastic ingestion by four seabird species in the Canadian Arctic: Comparisons across species and time

**Abstract:**

Plastic presence in the world's oceans has increased dramatically over the past few years, becoming a threat to marine wildlife especially top predators such as seabirds. Therefore, it is crucial to monitor plastic levels in the marine environment to understand its impacts, not only on threatened species but also on other species. Our study evaluates plastic ingestion in guanay cormorants (Phalacrocorax bougainvillii) through pellet analysis at ten colonies along the Peruvian coast between 2018 and 2019. A total of 2,286 pellets were collected and analyzed, of which plastic debris was present in 162 (10.8%) pellets (N = 1497) consisting of mainly user plastics and varying in size from mega (>20 mm) to micro (1-5 mm) plastics (nano plastics were not assessed). Micro and meso plastic (5-20 mm) were most abundant with 67% and 23% by number, respectively and the most common plastic colour found was white (27% by number). There was a significant difference in the percentage by the occurrence of plastic across regions, founding the highest score of plastic on the central coast of Perú. We also found a significant relationship between the percentage occurrence of plastic debris in pellets and the presence of river mouths closer to the colonies. Plastic ingestion by guanay cormorants reveals that plastic has already been transferred into the Peruvian marine food web. This study is the first of its kind in the Peruvian marine environment and the results set a baseline for future studies of plastic pollution in the Peruvian sea.

**Authors:**

Isabella Diaz¹, Carlos Zavalaga¹, Bethany Clark²

¹Universidad Cientifica del Sur, ²BirdLife International

Guanay cormorant pellets (Phalacrocorax bougainvillii) as an indicator of marine plastic pollution along the Peruvian coast

**Abstract:**

Brown skuas (Stercorarius antarcticus lonnbergi) are opportunistic predators and scavengers. Here, we measured total mercury (THg) concentrations in blood samples from adult brown skuas (n = 82) from three breeding sites across a latitudinal gradient in the Southern Ocean (SW Atlantic region): (i) Bahía Esperanza/Hope Bay, Antarctic Peninsula; (ii) Signy Island, South Orkney Islands; and, (iii) Bird Island, South Georgia. Blood THg concentrations increased from high Antarctic to low Antarctic latitudes, such that Hg contamination was lowest at Bahía Esperanza/Hope Bay (mean ± SD, 0.95 ± 0.45 µg g-1 dw), intermediate at Signy Island (3.42 ± 2.29 µg g-1 dw) and highest at Bird Island (4.47 ± 1.10 µg g-1 dw). Blood THg concentrations were also related positively to δ15N values, reflecting the biomagnification process. Males had higher Hg burdens than females, likely reflecting deposition into the egg by females and potentially differences in trophic ecology. These data provide important insights into Hg transfer to Southern Ocean seabirds.

**Authors:**

William Mills¹, Andrés Ibañez², Paco Bustamante³, Ana Carneiro⁴, Stuart Bearhop⁵, Yves Cherel³, Rocío Mariano-Jelicich⁶, Rona McGill⁷, Diego Montalti², Stephen Votier⁸, Richard Phillips¹

¹British Antarctic Survey, ²Museo de La Plata (FCNyM-UNLP, CONICET), ³CNRS-La Rochelle Université, ⁴BirdLife International, ⁵University of Exeter, ⁶Universidad Nacional de Mar del Plata, ⁷Scottish Universities Environmental Research Centre, ⁸Heriot-Watt University

Latitudinal and sex differences in mercury contamination of brown skuas in the Southern Ocean

**Abstract:**

The study of the use of space in seabirds had increased exponentially due to the use of biologging devices and the statistical techniques to extract and analyze large datasets. One of these statistical techniques is the Hidden Markov Models (HMM), which allow the identification of different behaviors of birds during their trips. Currently, few studies have been carried out to evaluate the classification accuracy of HMMs at different sampling frequencies. In this sense, the goal of the present study is to quantify the effect of sampling frequencies on the identification of foraging areas using HMMs in two tropical seabirds (31 trips of Sula leucogaster and 16 trips of Phaethon aethereus), with different GPS sampling frequencies (1/min and 1/15min, respectively). In addition, in both species we used pressure sensor data where dives were identified, used to validate HMM results. To identify foraging states we fitted HMMs to GPS datasets from both seabirds. To validate the classification accuracy of the HMMs, the data classified as foraging were contrasted with the dives and were calculated the precision, sensitivity and specificity measures. Subsequently, kernel densities were estimated for foraging and dives datasets and the overlap between them was calculated as a proxy for overall accuracy. Results showed that the classification ability of the HMMs was 81% for S. leucogaster, while for P. aethereus it was 48%. On the other hand, the kernel overlap values of foraging and diving were higher than 95% for both species. The present study demonstrated that the classification ability of HMMs in data with low sampling frequency (i.e. 1/15min) could present a high error percentage at the individual level. However, the high kernel overlap value (>95%) shows that at the population level it is possible to use low sampling frequencies to identify foraging areas.

**Authors:**

Fiorella Vilela¹, Sophie Bertrand², Marcio A. Efe³, Leandro Bugoni⁴, Guilherme T. Nunes¹

¹Universidade Federal do Rio Grande do Sul, ²Institut de Recherche pour le Développement (IRD), ³Federal University of Alagoas, ⁴Universidade Federal do Rio Grande

Effort of sampling frequency on foraging trip segmentation in tropical seabirds

**Abstract:**

The migratory behaviour of the Yelkouan Shearwater, a seabird endemic to the Mediterranean Sea and classified 'Vulnerable' according to IUCN criteria, remains poorly understood to date. While Yelkouans of various Mediterranean origins (Malta, France, Greece) have been sighted occasionally from summer to autumn as far as the Black Sea, others have been observed in the southern Mediterranean waters. Here we describe for the first time the post-breeding journeys of 11 adults from a colony in Lastovo Archipelago, central Adriatic (Croatia) which we equipped in late June 2021 with ultra-light GPS-GSM loggers that are still active at the time of this writing. The results display a strong variability in the journeys of individuals from the same nesting site. In the space of only six weeks, three adults had already traveled over 2500 km, following the same route although days apart, to reach the pelagic waters of the Black Sea. At least one of them was tracked all the way till the entrance of the Azov Sea - a major spawning ground for anchovies. Others stopped their journey - for weeks at least - in islands of the Aegean Sea, home to many yelkouan nesting colonies. Other individuals kept foraging between the Italian and Croatian coasts of the Adriatic Sea, while others limited their flights to the vicinity of their nests in the Lastovo archipelago. Our preliminary conclusions underline the similarity of the long, rather precise, migratory route followed by the yelkouans to reach the Black Sea. Our study raises many further questions: to begin with, what is the precise stimulus that triggered the start of their respective migration?

**Authors:**

Loriane MENDEZ¹, Sven Kapelj², Paula Moschella¹, Frederic Briand¹

¹CIESM (Mediterranean Science Commission), ²Association BIOM

The summer migration of the Yelkouan Shearwater (Puffinus yelkouan) from a single island in Croatia

**Abstract:**

The likelihood of conservation strategies being successful increases when the varying ecologies of an animal during all life-history stages are considered, particularly during those which the animal is more vulnerable. For example, penguins are land bound and unable to feed for several weeks when they undergo their annual catastrophic moult. If they are unable to accumulate sufficient fat stores before and after this critical life history stage, they are unlikely to survive or it could have adverse carry-over effects into the following breeding season. Over the past 20 years, the population of the Endangered African penguin Spheniscus demersus has followed the declining trend in the availability of their main prey, sardine Sardinops sagax and anchovy Engraulis encrasicolus. Subsequently, to improve prey availability, conservation efforts have focused on spatial management strategies to reduce resource competition with purse-seine fisheries during the breeding season. To date, these spatial management strategies have not considered the spatial distribution of the penguins during other critical life-history stages. Using GPS tracking data collected between 2012 and 2019, we identify important foraging areas for pre- and post-moult African penguins at three of their major colonies: Dassen Island and Stony Point (Western Cape) and Bird Island (Eastern Cape). The at-sea distribution of non-breeding adults (c. 600 km from colony) was far greater than that observed for breeding birds (c. 40 km from colony) and varied considerably between sites, years and pre- and post-moult stages. However, waters within 20 and 40 km of their breeding colonies were intensively used and represent important foraging areas to non-breeding birds. Our findings identify important marine habitats for non-breeding African penguins and provide support for the expansion of fisheries-related spatio-temporal management strategies to help conserve African penguins outside the breeding season.

**Authors:**

Tegan Carpenter-Kling¹, Andrew deBlocq¹, Christina Hagen¹, Craig Harding², Taryn Morris¹, Lorien Pichegru³, Peter Ryan², Jennifer Roberts², Ross Wanless¹, Alistair McInnes¹

¹BirdLife South Africa, ²University of Cape Town, ³Nelson Mandela University

Surviving catastrophe: important marine area use of non-breeding African Penguins supports proposed conservation strategies for breeding birds

**Abstract:**

Post-breeding migrations from temperate latitudes allow animals to improve survival by tracking food supplies and seeking out milder climatic conditions. In long-lived species such as seabirds, which have several years of immaturity before becoming breeders, successful migration is a key parameter influencing long-term population dynamics. Most seabird tracking studies have focused on adult behaviour during the breeding season but developments in tracking technology are now opening up opportunities for exploring behaviour during earlier life stages and larger-scale movements during migration. Adult Northern gannets show individual heterogeneity in the timing and route choice of their southerly migration as well as in their overwintering locations. However there is currently no data on the behaviour of juvenile gannets which fledge at approximately 13 weeks, after which they are entirely independent of their parents. Tracking their behaviour during this early life stage is vital for understanding dispersal and survival and may have consequences for conservation measures, which are currently based solely on data for adults. We attached Argos GPS-PTTs to 42 fledgling gannets on the Bass Rock, Scotland in 2018 and 2019. Here we present the first GPS and satellite tracking data for these birds during their initial few weeks at sea, providing new insights into the timing, route choices and staging grounds used by birds on their maiden migration.

**Authors:**

Jude Lane¹, Keith Hamer¹

¹University of Leeds

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The shearwater and the bottlecap: understanding the broader impacts of plastic ingestion on seabirds

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