United States

**Abstract:**

Most petrels are nocturnal on land and use calls as the main channel of communication among them. Gadfly petrels, especially unpaired birds, use aerial calling during their courtship flights, but factors influencing this behaviour are poorly studied. The Cape Verde petrel (Pterodroma feae) is a gadfly petrel endemic of Cabo Verde, breeding secretively at low densities in the mountains, where they seldom vocalize. In contrast, they are extremely noisy during courtship flights, which normally occurs over the top of high mountain areas of difficult access, thus complicating the study of their call behaviour. In this study, we deployed sound recorders at the main courtship areas located at the four islands (Santo Antão, São Nicolau, Santiago and Fogo islands) where Cape Verde petrels breed to shed a light on the courtship behaviour. Sound recorders were programmed to register sounds up to 48KHz from sunset to midnight for 5 min recording intervals every 5 minutes for a minimum of 2 months of continuous recording. We evaluated how the call behaviour was influenced by the hours since the sunset and the moon cycle and how it varied by island and throughout the breeding season. We found a lower number of calls in nights with high moonlight intensity, typically in the previous days to full moon and during the first hours after sunset. There were important differences across islands, probably reflecting distinct bird abundances. The peak of callings occurred during the pre-laying and hatching periods, probably matching the main courtship periods, i.e., before laying and after early breeding failure. The Cape Verde petrels are being threatened by light and noise pollutions and by the construction of anthropogenic infrastructures at the study courtship areas. The use of sound recorders can facilitate the monitorization of seabirds&#39; activity with low economical and logistic effort, the assessment of the impact of on-land threats and help seabird conservation management.

**Authors:**

Teresa Militão¹, Júlia Pujol-Casado¹, Manuel Rodríguez¹, Jacob González-Solís¹

¹University of Barcelona

3rd World Seabird Conference

Courtship activity of the secretive Cape Verde petrel: a multi-locality approach using sound-recorders

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:**

Most petrels are nocturnal on land and use calls as the main channel of communication among them. Gadfly petrels, especially unpaired birds, use aerial calling during their courtship flights, but factors influencing this behaviour are poorly studied. The Cape Verde petrel (Pterodroma feae) is a gadfly petrel endemic of Cabo Verde, breeding secretively at low densities in the mountains, where they seldom vocalize. In contrast, they are extremely noisy during courtship flights, which normally occurs over the top of high mountain areas of difficult access, thus complicating the study of their call behaviour. In this study, we deployed sound recorders at the main courtship areas located at the four islands (Santo Antão, São Nicolau, Santiago and Fogo islands) where Cape Verde petrels breed to shed a light on the courtship behaviour. Sound recorders were programmed to register sounds up to 48KHz from sunset to midnight for 5 min recording intervals every 5 minutes for a minimum of 2 months of continuous recording. We evaluated how the call behaviour was influenced by the hours since the sunset and the moon cycle and how it varied by island and throughout the breeding season. We found a lower number of calls in nights with high moonlight intensity, typically in the previous days to full moon and during the first hours after sunset. There were important differences across islands, probably reflecting distinct bird abundances. The peak of callings occurred during the pre-laying and hatching periods, probably matching the main courtship periods, i.e., before laying and after early breeding failure. The Cape Verde petrels are being threatened by light and noise pollutions and by the construction of anthropogenic infrastructures at the study courtship areas. The use of sound recorders can facilitate the monitorization of seabirds' activity with low economical and logistic effort, the assessment of the impact of on-land threats and help seabird conservation management.

**Authors:**

Teresa Militão¹, Júlia Pujol-Casado¹, Manuel Rodríguez¹, Jacob González-Solís¹

¹University of Barcelona

poster

**Abstract:**

The Southern Ocean provides important breeding and foraging habitats for numerous marine predators, many of which rely on Antarctic krill Euphausia superba as their main prey item. Krill are also the target of a commercial fishery, which has the potential to reduce prey availability to dependent predator species. Alternatively, krill-dependent predators and the krill fishing industry may co-exist with no negative impacts if krill is abundant and catch limits account for predator requirements. In order to manage the krill fishery in such a way as to limit potential negative impacts on marine predators it is important to identify areas which are important to krill-dependent predators. We have developed a suite of habitat models, to predict the density distributions of 14 species of krill-dependent predators including penguins (3 species), procellariform seabirds (8 species) and cetaceans (2 species) during austral summer. Additionally, we have estimated the total krill consumption by each predator species by collating energy requirements and diet composition from the scientific literature. By combining species-specific estimates of krill consumption with species distributions predicted from our habitat models we have created a series of spatially explicit estimates of krill consumption across the Antarctic Peninsula and South Shetland Islands. We found high inter-specific variation in the spatial distribution of krill consumption, and some overlap between predator consumption and the krill fishery. However, understanding the possible impacts of the fishery on marine predators remains challenging due to important gaps in our understanding. These include i) spatio-temporal mismatches between predator data and the krill fishery, ii) the impact of krill transport, downstream impacts and replenishment rates, iii) disruption of krill swarms, and iv) seasonal variation.

**Authors:**

Victoria Warwick-Evans¹, Luciano Dalla Rosa², Jefferson Hinke³, Norman Ratcliffe¹, Jarrod Santora⁴, Eduardo Secchi², Elisa Seyboth², James Waggitt⁵, Phil Trathan¹

¹British Antarctic Survey, ²Federal University of Rio Grande, ³NOAA, ⁴University of California Santa Cruz, ⁵Bangor University

Competition or coexistence? Krill utilisation by marine predators and the krill fishing industry

**Abstract:**

The first preliminary estimates of seabird bycatch mortality from certain fishing gears of the UK-registered fishing fleet in UK and adjacent waters (Northridge et al., 2020) suggest considerable mortalities for some species. Here we present the results of a Population Viability Analysis (Miles at al., 2020) that estimates the relative population gains that UK seabirds could theoretically achieve if these estimated levels of mortality were to be eliminated by bycatch mitigation measures (and assuming no other pressures are operating). Preliminary results indicate that bycatch mitigation would benefit great cormorant and northern fulmar the most, resulting in a population increase after 25 years of approximately 2% and 7%, respectively (assuming a density-dependent response in growth rate with increased population size). Regional breakdowns identified potentially even greater gains. As part of international efforts, we summarise work undertaken by the UK fishing industry, in partnership with governments and scientists, to reduce bycatch. We conclude by exploring evidence gaps, related challenges and potential solutions.

**Authors:**

James Miles¹, Matt Parsons², Catharine Horswill³

¹University of Southampton, ²Joint Nature Conservation Committee, ³ZSL Institute of Zoology and University College London

Estimating seabird population responses to bycatch mitigation in UK fisheries

**Abstract:**

Quantifying spatial and temporal variations in the distribution of seabirds is a fundamental component of their conservation. A common approach uses vessels or aircraft to record animals along transect lines, and species distribution models or geostatistical interpolation to produce density surfaces. However, individual surveys cannot record distributions at annual, seasonal and continental scales. The tendency to use spatiotemporally explicit information when constructing density surfaces also produces outputs representing instantaneous distributions at the time of surveys or the intensity of survey effort, rather than overall distributions. This study uses a combination of methods to produce density surfaces of 12 species at a monthly and 10km resolution over 30 years in the north-eastern Atlantic. First, 1.6 million kilometers of surveys were collated from 15 sources. Second, ecologically informed species distribution models based on relevant environmental variables were developed. This approach produced sensible estimations of seasonal distributions. These widely applicable approaches provide inputs into a range of complementary analyses into ecosystem-level processes, as well as management strategies aiming to identify and mitigate impacts on populations.

**Authors:**

James Waggitt¹, Peter Evans¹

¹Bangor University

Ecologically informed distribution maps for seabird communities in the north-eastern Atlantic Ocean

**Abstract:**

European shags (Gulosus aristotelis) are vulnerable to disturbance by boats and to bycatch in gillnet fisheries and the population is in decline. Intensified coastal development, e.g. aquaculture and kelp harvesting, pose potential additional threats that call for impact assessments and marine spatial planning. As European shags breed in numerous colonies scattered along the coastline, it is a challenge to identify and protect the most critical foraging habitats. Even with existing knowledge about the location of the colonies, it remains an implausible task to document the habitat use for each and every colony, although this is highly relevant information for management purposes. Predicting foraging areas of a given population based on the tracking information from birds in other colonies could be a solution to this dilemma. Here, we analysed tracking data from five different European shag colonies spread along the Norwegian coast over a latitudinal gradient of more than 1700 km: Hornøya (70°23'N, 31°09'E), Røst (67°26'N, 11°54'E), Sklinna (65°12'N, 10°59'E), Runde (62°23'N, 5°36'W), and Jarstein (59°09'N, 5°10'E). Minimum two and maximum ten years of tracking data existed for each colony. For each colony we identified the foraging areas and their environmental characteristics (depth, presence/absence of kelp forest, bottom substrate...) and quantified the consistency in foraging areas between years. We then predicted the foraging areas of a given colony based on the results from the other colonies and compared the modelled results with the true data to test the performance of the predictions. Our research will contribute to strengthen our understanding of the foraging ecology of European shags, and help identify the most important foraging areas required for their conservation. More generally, our results can help to improve the use of tracking data for marine spatial planning.

**Authors:**

Nina Dehnhard¹, Signe Christensen-Dalsgaard¹, Jenny Mattisson¹, Arnaud Tarroux¹, Tycho Anker-Nilssen¹, Svein-Håkon Lorentsen¹

¹Norwegian Institute for Nature Research (NINA)

Multi-year and multi-colony tracking of European shags ? towards better predictions of foraging habitats within and between colonies

**Abstract:**

The effects of intraspecific competition on seabird foraging movements are relatively well studied, but the impacts of predation are less well known. Many seabirds are apex predators, but the small size of storm petrels puts them at risk of predation by other seabirds. Predation risk has a strong influence on the nesting location and breeding behaviour of storm petrels but does predator avoidance also reduce the potential foraging area available to these small species? We have GPS tracked European Storm Petrels (Hydrobates pelagicus) breeding on Mousa, Shetland, UK between 2014 and 2018. Using data on predator distributions and remotely-sensed environmental data, including sea-surface temperature and wind speed, we investigate the relative influence of a variety of factors on storm petrels' movements and at-sea distributions. We provide new insights into the at-sea ecology of one of the world's smallest seabirds.

**Authors:**

Zoe Deakin¹, James Waggitt², Peter Evans², Rob Thomas¹, Renata Medeiros¹, Frank Hailer¹, Mark Bolton³

¹Cardiff University, ²Bangor University, ³Royal Society for the Protection of Birds

A quiet corner of the playground? The influence of predator distributions, intraspecific competition and environmental conditions on the movements and marine distribution of European Storm Petrels

**Abstract:**

The Caribbean region supports 23 extant breeding species of seabirds on nearly 900 colonies and breeding sites. Despite the large area, numerous species and colonies, conservation concern for many species, and proximity to the USA, surprisingly little is known about the ecology of seabirds in this region particularly during the nonbreeding season when birds are away from colonies for extended periods of time. We used geolocators to track the movement patterns of White-tailed Tropicbirds (Phaethon lepturus) breeding in the Bahamas. Although basic use areas at sea have been described for the species, here we assess the level of fidelity to use areas from five consecutive years of tracking data from two individuals tagged at the same colony in the Exumas. During the breeding season tropicbirds consistently frequented the northern Bahamas but also used waters adjacent to Cuba. During the nonbreeding season individuals dispersed north but also were frequently located east of Bermuda and in waters towards the mid-Atlantic ridge. Each bird showed a relatively high degree of fidelity to use areas among years. There was also a relatively high degree of overlap between the two individuals each year. Furthermore, use areas often overlapped with the location of the Sargasso Sea, an ocean gyre system in the western north Atlantic that concentrates sargassum, spawning and subadult eels, and other large marine vertebrates. Our data suggest that tropical seabirds in the north Atlantic may not only wander throughout pelagic waters but also may frequent specific marine regions where productivity is enhanced.

**Authors:**

Patrick Jodice¹, Will Mackin², Autumn-Lynn Harrison³, Yvan Satge⁴, Bradley Wilkinson⁴

¹USGS/Clemson University, ²Terra Mar Applied Sciences, ³Smithsonian Conservation Biology Institute, ⁴Clemson University

High site fidelity in a tropical seabird during the nonbreeding season: a 5-year case study

**Abstract:**

The Olrog's Gull (Larus atlanticus) is endemic to the Atlantic coast of southern South America and a species regionally listed as threatened, with the bulk of its diet comprised by crabs, at least in breeding sites and some non-modified wintering areas. Here we evaluate the effect of the group size and sex variability on the foraging behavior of wild immature gulls during the non-breeding season in Mar Chiquita coastal lagoon, Argentina. Birds were captured, sexed and banded during the 2016 non-breeding season. Foraging behavior was quantified by focal observations made on banded individuals, the size of the foraging group, and the size and type of preys were recorded. Foraging parameters estimated were (1) foraging effort (capture attempts per minute), (2) capture rate (prey obtained per minute), and (3) foraging efficiency (consumed biomass per minute). Males spent more time performing agonistic behavior than females (GLMM: z=2.43, p<0.05). The time spent resting and the foraging effort increased significantly with group size (GLMM: z=2.03, p<0.05; z=2.20, p<0.05, respectively). Males showed a preference for larger crabs (Ordinal Mixed Model-OMM, z=1.99, p<0.05) and captured smaller crabs (OMM, z=-2.03, p<0.05) at a higher capture rate (GLMM, z=2.09, p<0.05) with the increase of group size. Also, the duration of receiving agonistic behavior, size of prey and the foraging effort (LRT: χ2=4.92, P<0.05; χ2=9.73, P<0.05; χ2=4.97, P<0.05, respectively) were affected by individual identity. The present study is the first one addressing foraging variability for Olrog's gulls with individuals of known identity. We corroborate the hypothesis that both, intrinsic and extrinsic factors affect the foraging behavior of the Olrog's gull. Results illustrate what we can learn from modeling individual variation in the study of foraging behavior.

**Authors:**

Francisco Zumpano¹, Melina Castano¹, Favero Marco¹, Garcia German¹

¹Instituto de Investigaciones Marinas y Costeras (IIMyC), UNMdP - CONICET, Rodriguez Peña 4046 Nivel

Sex and group size variability affecting the foraging behavior of Olrog's gulls (Larus atlanticus)

**Abstract:**

Parental investment is any action of the parents that generates costs in their biological efficacy, but benefits their offspring. In birds it shows at any stage of reproduction: egg laying, incubation and chick rearing. Hatching asynchrony (HA) and egg size dimorphism (ESD) generate an intra-clutch hierarchy that affect growth and survival of Magellanic penguin's chicks. In our study colony (Ría Deseado, Argentina; 47°45'S, 65°53'W) females in a better body condition lay larger second eggs but also, both parents´ condition determine nestling growth. Therefore, parental body condition can mask the effect of the egg volume and HA on intra clutch hierarchy. Using a cross-fostering experiment we were able to disentangle the effect of HA and ESD from parental body condition. We found that hatching asynchrony had a negative effect on last-hatched chicks, but this disadvantage was mitigated by egg size dimorphism in their favor. Moreover, females in good condition invest more in second than in first chicks, which, added to a greater investment by foster fathers, leading to offspring fledging in good condition. On the contrary, for the first-hatched chicks, we found that body condition of the biological father was an important factor for their growth. We conclude that raising more than one chick seems to be a decision based on parental condition throughout the breeding season.

**Authors:**

Nahuel Marchisio¹

¹CONICET

Intra-clutch factors affecting growth and fledgling success of Magellanic penguin chicks: A cross fostering experiment

**Abstract:**

Animal personality is defined as consistent between-individual differences that are stable across contexts and persist through time. These between-individual differences can result in divergent foraging behaviour and reproductive success and influence how individuals respond to environmental change, with the potential to alter population dynamics. Although personality has been found in numerous taxa throughout the animal kingdom, few studies have focused on seabird species. This study aimed to determine whether personality can be identified in razorbills (Alca torda) from the family Alcidae. Three tests of personality were carried out on chick-rearing razorbills (n=31) during 2021 in coastal Newfoundland, Canada, to quantify the frequency of personality traits along the shy-bold continuum. Personality tests involved quantifying behavioural responses to extraction from the rock crevice breeding site and to a period of restraint, along with human ratings of boldness for each individual. Preliminary findings suggest these methods may be successful at identifying personality in this species, as razorbills exhibited a wide range of behavioural responses along the shy-bold continuum along with individual consistency between tests. Personality was investigated in relation to reproductive success, breeding site complexity and previous overwintering distribution. The next steps include repeating personality tests on these same individuals in subsequent years to test behavioural consistency across time and contexts (i.e. varying prey availability) and further relating these personality differences to variation in reproductive success and foraging/ movement patterns during the breeding and non-breeding season. This study represents a first step in quantifying personality in this alcid species, which will inform intraspecific response diversity and, thus, the ability of razorbills to cope with future environmental change.

**Authors:**

Matthew Legard¹

¹University of Manitoba

Courtship activity of the secretive Cape Verde petrel: a multi-locality approach using sound-recorders

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