United States

**Abstract:**

Introduction of exotic mammals like rats is one of the leading causes of island biodiversity loss, particulary for seabirds. Rat eradication generally has positive effects on seabirds but the demographic processes explaining these effects are not always understood. In this talk, we will present the evolution of the seabird community of Tromelin island (western Indian Ocean) after brown rats (Rattus norvegicus) eradication. Before rats introduction, in the XVIIIth century, 10 seabirds species were breeding on the island, totalling hundreds of thousands of pairs. In 2005, at the time of rat eradication, only 2 species (red-footed boobies (Sula sula) and masked boobies (Sula dactylatra)) were still breeding, totalling less than 400 pairs. In 2019, 15 years after rat eradication, 7 seabird species totalling more than 3000 pairs breed on the island. We determined the demographic parameters (breeding success, survival rate) of the two species that were still breeding in 2005 with capture-mark-recapture data. We built a matrix population model to estimate their annual population growth rate. This rate was 1.04 for red-footed boobies and 1.02 for masked boobies, which is in accordance with the observed growth. We estimated the carrying capacity of the island, as the maximum number of pairs that can breed on the island, knowing the area of favourable habitats. Carrying capacity was 18000 pairs for red-footed boobies and 27000 pairs for masked boobies. A density dependant matrix population model suggest that these populations could reach these value in 3 and 5 centuries, respectively. However these predictions should be interpreted with caution as the model does not include factors that may impact the growth of the populations : prey abundance, seabird induced changes in vegetation cover, interspecific competition and sea level rise which will reduce the area of suitable habitat, and increase the frequency of flooding events.

**Authors:**

Merlène Saunier¹, Matthieu Le Corre¹, Gabrielle Dicque¹, Maud Berlincourt¹, Morgane Manoury¹, Jean Hivert², Luc Gigord², Sabine Orlowski³, Florent Bignon³, David Ringler³

¹UMR ENTROPIE, university of Reunion Island, ²CBNM-CPIE Mascarin, ³TAAF

3rd World Seabird Conference

Demographic effects of rat eradication on a tropical seabird community

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:**

Haematologic analyses can reveal the physiological condition of birds, who are known to efficiently disguise symptoms of stress and disease. However, interpretation of such analyses requires species-specific baseline data, which are lacking for most free-living seabird species. We provide baseline reference data for several haematological parameters in Northern gannets (Morus bassanus) and combine this with telemetry and dietary data to understand the links between haemotologic condition and foraging behaviour. Blood samples were collected from breeding Northern gannets in July 2017 (n = 15) and 2018 (n = 28), which were also equipped with GPS tags. Smears were prepared for performing blood cell counts, including immature erythrocyte and microcyte percentages, total and differential leucocyte counts, heterophil:lymphocyte (H:L) ratio, and total thrombocyte count; the remaining blood was used for stable isotope analysis, and foraging behaviours were inferred from the recovered tag data. Blood cell counts revealed that the sampled birds were highly stressed and some showed an immune response, evident from the abnormal leucocyte counts and H:L ratio. There were no sex-related differences in haematological parameters or diet, in contrast to foraging parameters where females undertook longer trips than males and spent proportionately more time in search behaviours. The percentage time spent actively foraging was negatively correlated with the percentage of eosinophils. While there was no direct link between haematologic condition and diet, one bird feeding at a relatively low trophic level undertook exceptionally short foraging trips and showed abnormal blood cell counts. This suggests a link between haematologic condition and foraging ecology that can be employed in assessing seabird health.

**Authors:**

Zaraa Malvat¹, Sharon Lynch¹, Ashley Bennison¹, Mark Jessopp¹

¹University College Cork

Evidence of links between haematologic condition and foraging behaviour in Northern gannets (Morus bassanus)

**Abstract:**

Threatened species recovery is made challenging by a lack of clarity in the problems to be solved by groups of stakeholders, their competing management objectives and the diverse management alternatives that might be proposed. These factors are compounded by uncertain outcomes of interventions in data-poor species. Structured Decision Making (SDM) is a powerful process that works through these challenges, providing a framework to use appropriate scientific tools and allowing managers to make the best choice. Whilst SDM is widely used in resource management, its application to species recovery is rare. We used SDM to assist the Tara iti Recovery Group to develop a recovery plan for New Zealand's (NZ) rarest breeding bird. Tara iti, or NZ fairy tern (Sternula nereis davisae), has approximately 10-12 breeding pairs with little population growth over the last decade and no clear direction in what to do to promote population recovery. Working with multiple stakeholders, including the decision makers of NZ government and Māori (NZ's indigenous people), we identified fundamental objectives and a range of management alternatives. Using available data and expert elicitation, we predicted the consequences of each alternative on each objective, including building a set of stage-based population projection models. We addressed the biological uncertainty around novel alternative solutions, particularly for tern species, such as captive rearing and reintroduction, and compared these to more conventional field management alternatives. We then solved the optimal choice based on the decision-makers' values and risk attitudes. My research demonstrates how SDM provided a platform for all voices to be heard, and how its values-led approach is key to robust decision making for conservation of threatened species.

**Authors:**

Thalassa McMurdo Hamilton¹, Stefano Canessa², John Ewen³

¹Institute of Zoology, ZSL; UCL, ²University of Ghent, ³Institute of Zoology, ZSL

A structured approach to recovery planning for NZ's rarest breeding seabird

**Abstract:**

Diseases affect a large number of seabird species worldwide annually, and can cause high mortalities that are potentially conservation-threatening. The impacts of such mortality events on southern African seabirds is shown by the death of 1300 common terns due to avian influenza in 1961 and the death of over 14000 Cape cormorants due to avian cholera on Dyer Island in 2004/05. More recently, the 2017/18 outbreak of the H5N8 strain of avian influenza in domestic poultry and wild birds caused the death of more than 7500 seabirds in South Africa. The outbreak of avian influenza in South Africa has demonstrated the need for continuous disease surveillance and the need for outbreak preparedness plans in order to intervene as early as possible and prevent pathogens from spreading among seabird colonies. The Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) is a leader in Seabird disease surveillance and treats up to 2500 seabirds annually, of which 1500 are African penguins. The health and pathology research conducted at SANCCOB is ongoing and currently involves data collection, analysis, write-up and publication of data on work that has been done in the last 15 years at SANCCOB. This work functions as passive disease surveillance as well as providing information for evaluating disease risk to the seabird populations. We will highlight the gaps in the current monitoring and preparedness regarding seabird diseases and propose the establishment of an on-going disease surveillance programme. Improved outbreak response plans through expanded efforts to conduct post-mortem examination, laboratory tests for pathogens known to be of high conservation concern are needed to assist South African government (DEA), managing conservation authorities (Cape Nature and SANParks) and the state veterinary services in the development of a contingency plan for disease outbreaks in seabird colonies.

**Authors:**

Albert Snyman¹, Katta Ludynia¹, David Roberts¹

¹The Southern African Foundation for the Conservation of Coastal Birds (SANCCOB)

Bridging the gap: disease surveillance, response and planning for seabirds in South Africa

**Abstract:**

European Seabirds at Sea (ESAS) work was initiated in 1979 by various European institutions carrying out seabird distribution surveys at sea. The group achieved a standardization method of data collection, conducted large-scale ship-based surveys in the North Sea, established a joint ESAS database, published distribution maps, identified IBAs and carried out joint research projects. In the past decades, Seabirds at Sea work in Europe had a stronger national focus related to the implementation of marine protected areas and impact assessments regarding offshore windfarms. Joint activities ceased and comprehensive entries into the joint ESAS database were not continued after 2011. Recent years, however, have seen various new initiatives for joint Seabirds at Sea work. Under the impulse of the Dutch WOZEP research program, the ESAS database has undergone a major update with Dutch, Belgian and German data and a thorough restructuring of the data model. The updated version will soon be migrated to ICES Data Centre. The future database will provide the opportunity to hold ship-based as well as aerial survey data from different survey schemes. Importantly, the ESAS database will be more widely available to the research community, in line with the ICES open access data policy. There have also been renewed efforts for large-scale surveys and joint database analyses. In the Baltic Sea and southern North Sea, national at-sea survey efforts from 10 different countries were combined and synchronized to carry out a synoptic large-scale winter survey in early 2016 (with similar efforts in 2020/2021). Applying species distribution models, final products will comprise large-scale distribution maps and updates of population estimates to assess the current situation of seaducks and other species of high conservation concern. In addition, historical data as well as new data collections will flow into indicators assessing the marine environmental status according to regional sea conventions (OSPAR, HELCOM & MSFD) and feed into marine spatial planning.

**Authors:**

Nicolas Vanermen¹, Ainars Aunins², Volker Dierschke³, Stefan Garthe⁴, Mark Lewis⁵, Moritz Mercker⁶, Ib Krag Petersen⁷, Martin Poot⁸, Eric Stienen¹, Andy Webb⁹, Nele Markones¹⁰

¹Instituut voor Natuur- en Bosonderzoek (INBO), ²University of Latvia, ³Gavia EcoResearch, ⁴University of Kiel, ⁵JNCC, ⁶bionum, ⁷University of Aarhus, ⁸Statistics Netherlands (CBS), ⁹HiDef Aerial Surveying Ltd, ¹⁰Federation of German Avifaunists

The whole is more than the sum of its parts - joint European Seabirds at Sea activities

**Abstract:**

Seabird breeding distributions are often examined at the level of individual species, but many seabirds nest at multispecies sites. We explored the metacommunity structure of Antarctic Peninsula seabirds, which live in a simple environment, well-suited to examining occupancy patterns. Site-specific breeding status for every member of the metacommunity was modeled by a series of multi-state Bayesian occupancy models, using 22 years of data on species detection. Several lines of evidence, including the absence of significant coherence, lack of clustered assemblages in ordination and geographic space, and high dissimilarity of neighboring sites, led to the conclusion that this metacommunity was structured by a stochastic colonization process. This pattern is consistent with expectations from the neutral theory of biodiversity, although here is likely driven more by site fidelity and colonization history than is usually assumed. However, comprehensive abundance data for the guild of pursuit-divers showed strongly non-overlapping patterns in the regional concentration of population size, indicating that deterministic factors play a larger role in subsequent colony growth. Our study demonstrates the value of taking a multi-species approach to the study of seabird breeding distributions, and highlights the need for continued collection of comprehensive abundance data when possible.

**Authors:**

Michael Schrimpf¹, Heather Lynch¹

¹Stony Brook University

Range limits, breeding distributions, and the role of stochasticity in structuring the Antarctic Peninsula seabird metacommunity

**Abstract:**

Rocas Atoll (3°52′S 33°49′W) is the only atoll in the South Atlantic Ocean, located approximately 260 km off the Northeast coast of Brazil. Despite its small surface (two islets with a combined area of 0.36 km2), Rocas Atoll is home to approximately 150,000 seabirds. Five species breed on the atoll: Black Noddy (Anous minutus), Brown Noddy (Anous stolidus), Sooty Tern (Onychoprion fuscatus), Masked Booby (Sula dactylatra), and Brown Booby (Sula leucogaster). Additionally, small numbers of Red-footed Booby (Sula sula) and Magnificent Frigatebird (Fregata magnificens) also roost on the islets. In June 2017, blood was collected from the tarsus (Suliformes) or jugular vein (Charadriiformes) of 214 seabirds: 26 A. minutus, 42 A. stolidus, 46 O. fuscatus, 33 S. dactylatra, 27 S. leucogaster, 20 S. sula, and 20 F. magnificens. Thin blood smears were freshly prepared, fixed with methanol, stained with Rosenfeld-Giemsa, and examined under the microscope. Two blood parasites were detected: Babesia sp. in Brown Booby (prevalence = 44%) and Haemoproteus sp. in Magnificent Frigatebird (prevalence = 10%). Although a previous study had detected DNA of Haemoproteus sp. in the blood of Brown Noddy, this parasite was not seen in this species' blood smears. Leukocyte profiles were generally similar across species and age groups, with the following averages (mean ± S.D.): heterophils 40.3%±15.9%, lymphocytes 53.8%±15.9%, monocytes 4.2%±3.9%, eosinophils 1.7%±3.0%, and basophils 0%±0.1%. The proportion of eosinophils was highest in S. dactylatra and S. leucogaster, especially in adults, suggesting a higher exposure to helminth parasites. The heterophil-to-leucocyte ratio, an indicative of physiological stress, was higher in adults than in chicks and immatures in most species, with the exception of A. stolidus where an opposite pattern was noted. This is the first hematological study of seabirds at Rocas Atoll, and is part of a broader health survey program that aims to identify pathogens and health challenges that may bear significance for seabird conservation at Brazil's oceanic islands.

**Authors:**

Ralph Vanstreels¹, Daniela Mariani², Renata Hurtado¹, Veridiana Galizia³, Maurizélia Silva⁴, Jean Ramos Silva²

¹Institute of Research and Rehabilitation of Marine Animals, ²Universidade Federal Rural de Pernambuco, ³Autonomous veterinarian, ⁴Instituto Chico Mendes de Conservação da Biodiversidade

Hematology and blood parasites of seabirds at Rocas Atoll, Brazil

**Abstract:**

Migration is common throughout the animal kingdom, while individuals often move to areas of high productivity, travelling long distances can be costly. Hence, the migration season can influence individual fitness as it is key in acquiring the energy required for reproduction. Recent studies have highlighted the important interaction between migration and breeding behaviour and identified so called ?carry-over? effects where behaviour in one period affects the behaviour in the other. In this study, we examine the foraging effort of Wandering albatrosses (Diomedea exulans) during migration and breeding to determine their effect on fitness. Using seven years of tracking data from a population on the Crozet Islands we examined the importance of age and sex on foraging effort (i.e. flight duration and take-offs). We found the foraging effort was greater for females and decreased with age. Past reproductive successes had an influence on the foraging effort during migration, which subsequently had an effect on the reproductive successes in the next breeding season. Birds with lower energetic costs before the breeding season were more successful breeders. Overall, the breeding season was more costly. This study highlights the importance of linking both seasons when trying to understand the life-history of the wandering albatross.

**Authors:**

Milena Cairo¹, Samantha Patrick¹, Henri Weimerskirch²

¹University of Liverpool, ²Centre d'Etudes Biologiques de Chizé, CNRS;Université de La Rochelle

The foraging effort of the Wandering albatross (Diomedea exulans) during breeding and migration seasons

**Abstract:**

Seasonal and annual climate variation is linked to fluctuations in resource abundance and/or distribution. In adverse conditions, animals with flexible foraging behaviours are more likely to find enough of these resources to sustain both self-maintenance and reproduction. In light of rapid habitat changes due to global warming and habitat degradation, plasticity in foraging behaviour has important implications for population trajectories. Here, the foraging behaviour of four sub-Antarctic albatross species was investigated from 2015/16 to 2017/18, a period that was characterized by pronounced climatic variability. Over three breeding seasons on Marion Island, GPS dataloggers were deployed on incubating wandering (WA), grey-headed (GHA), sooty (SA) and light-mantled (LMA) albatrosses to track there at-sea distribution. The response of birds to environmental variability was investigated by quantifying changes in their foraging behaviour along two axes: spatial distribution, using kernel density analysis, and foraging habitat, using generalised additive models and Bayesian mixed models. Our results suggest that during incubation, the albatross species have different foraging strategies and levels behavioural flexibility when responding to environmental variability. The WA appear as foraging habitat generalist, with individuals foraging in different habitats during a foraging trip. In contrast, the three smaller albatrosses exhibited interannual differences in foraging habitats. The generalist habitat-use of the WAB and differential habitat use of the GHA, DMA and LMA suggests that these species might be resilient to predicted changes in climate. Future investigations of marine predator response to environmental variability are likely to benefit from coupling information on foraging behaviour with demographics. This will allow for better understanding of the link between behavioural plasticity and population responses.

**Authors:**

Tegan Carpenter-Kling¹, Ryan Reisinger², Florian Orgeret¹, Maelle Connan¹, Pierre Pistorius¹

¹Marine Apex Predator Research Unit (MAPRU), Institute for Coastal and Marine Research, FitzPatrick I, ²Centre d'Etudes Biologiques de Chizé, UMR 7372 du CNRS-La Rochelle Université

Faithful nomads and flexible faithfulness: foraging behaviour of four sympatric albatross species in a dynamic environment

**Abstract:**

Seabirds and fisheries often compete for the similar pelagic resources, i.e. forage fish. Fisheries management, where present, normally focuses on maximizing long-term harvest (BMSY), which may or may not be compatible with conservation of fish-eating seabirds. We investigate the compatibility between different fisheries management targets and seabird productivity using a bio-energetic model that mechanistically links fish abundance with seabird foraging and energy expenditure. We parameterize the model for a large colony of common murres Uria aalge and razorbills Alca torda in the Baltic Sea (57° N, 17° E) and show that current fisheries management targets for their main prey, sprat Sprattus sprattus and herring Clupea harengus allows for further seabird population growth. This finding is consistent with observed increases in abundance of both species. We validate the model with regards to seabird-driven depletion of prey around the colony, using an unmanned surface vessel (USV) equipped with a broadband echo-sounder. The USV, a sailing drone remotely operated via satellite communication, was used for 40 days around the colony in 2019 with plans for re-deployment in April - July 2020. It provides continuous measurements of acoustic backscatter which is translated into area, time and depth specific biomass estimates for the forage fish. We discuss how USV technology in combination with seabird biologging and bio-energetic modelling can provide estimations of prey needed to sustain important seabird colonies, relevant to forage fish management.

**Authors:**

Jonas Hentati Sundberg¹, Agnes Olin², Natalie Isaksson³, Tom Evans⁴, Per-Arvid Berglund⁵, Aron Hejdström⁶, Olof Olsson⁷

¹Swedish University of Agricultural Sciences, ²University of Strathclyde, ³University of the highlands and islands, ⁴Marine Scotland, ⁵Baltic Seabird Project & Swedish Museum of Natural History, ⁶Baltic Seabird Project, ⁷Stockholm University

Sustainable fisheries for seabirds: Defining prey density thresholds through a combination of bio-energetic modeling, bio-logging and an unmanned surface vessel

**Abstract:**

Quantifying the foraging ecology of seabirds is key to understanding the population dynamics of both predator and prey. Generalist populations can show wide within-population variation in their diet, whereby some individuals exploit a narrower trophic niche compared to the total niche of the population. Understanding the role of individual variation and specialisation within populations is challenging but it is valuable for improving our knowledge on population dynamics and predator-prey interactions. Great black-backed gulls, Larus marinus, are generalists, although wide variability in diet is found between individuals of the same population. They regularly include other seabirds in their diet and, occasionally, specialise on them. They can therefore negatively impact seabird populations, as previously demonstrated in Larus and Stercorarius species. Despite this, the foraging ecology of Great Black-backed Gulls has not been thoroughly studied. In this study we plan to use a multi-technique approach including bio-logging and biochemistry to quantify gull habitat use, foraging energetics, and diet. We are also exploring the effects of sex and age-class on these parameters. Lastly, we are building on previous research at the study colony on the Isle of May (south-east Scotland), which has shown that a proportion of gulls specialise on sympatrically breeding Atlantic puffins Fratercula arctica and European rabbit Oryctolagus cuniculus. We use these findings to improve our understanding of Great Black-backed Gull foraging ecology and potential impacts on prey populations.

**Authors:**

Samuel Langlois¹, Francis Daunt², Jared Wilson³, Nina O'Hanlon⁴, Elizabeth Masden⁴

¹University of the Highlands and Islands, ²Centre for Ecology and Hydrology, ³Marine Scotland Science, ⁴Environmental Research Institute

Demographic effects of rat eradication on a tropical seabird community

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Demographic effects of rat eradication on a tropical seabird community

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Evidence of links between haematologic condition and foraging behaviour in Northern gannets (Morus bassanus)

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Can AI revolutionize seabird feeding watches?

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