United States

**Abstract:**

Habitat partitioning, wherein species that occupy the same geographic areas select different locations or resources, is considered key to the coexistence of closely related sympatric species. However, partitioning can be difficult to observe in natural settings due to the complexity of measuring niche breadth across relevant environmental features. Sea ducks, which overlap extensively throughout the annual cycle and utilize similar marine areas during non-breeding, provide an opportunity to apply concepts of habitat partitioning to understand how multiple species can effectively coexist while utilizing shared resources. We collected satellite telemetry data on annual cycle movements of over 500 individual sea ducks of five species (Black Scoter, Surf Scoter, White-winged Scoter, Long-tailed Duck, and Common Eider) from throughout eastern North America and the Great Lakes. To investigate marine habitat partitioning during the non-breeding season, we applied a multivariate habitat selection analysis and compared selectivity values across species, seasons, and environmental characteristics. Our results suggest that niche separation and habitat selectivity are strongest during the post-breeding molt and migration period, when highly productive habitats are spatially limited and individual mobility is restricted. During winter, species show strong preferences for productive nearshore marine habitats, but also overlap extensively in shared habitat areas. Conversely, during spring migration, species show little habitat selectivity or partitioning, suggesting that factors other than environmental covariates are driving habitat use. We discuss the conservation implications of seasonal variation in habitat partitioning and selectivity, and identify key multi-species habitat features used throughout the annual cycle.

**Authors:**

Juliet Lamb¹, Peter Paton¹, Jay Osenkowski², Scott McWilliams¹

¹University of Rhode Island, ²Rhode Island Department of Environmental Management

3rd World Seabird Conference

Seasonal habitat partitioning by sympatric sea ducks in eastern North America

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:**

Restricted breeding seasons are typical of most petrels, apart from some members of the genus Pseudobulweria. The Kermadec petrel Pterodroma neglecta, has been reported as both a winter and summer breeder but no substantive studies have corroborated this. Despite its wide distribution in 10 islands or island groups over the Pacific, the species' isolation on oceanic islands makes anything other than cursory reports possible. Here we investigate the breeding demography of Kermadec petrels over four years on Phillip Island (off Norfolk Island)in the South Pacific. The colony (ca. 50 breeding pairs) was visited for between 1 to >10 days approximately bi-monthly since January 2017. Most nesting attempts have been monitored with surveillance cameras and approximately 50% of breeding birds are currently fitted with Global Location Sensors (GLS). While seasonal peaks in breeding occur in the austral Spring and Summer, smaller numbers breed at other times of the year. While we observed most Kermadec Petrels did not alter the timing of egg-laying from season to season, a single example of delayed laying of 2.5 to 16 weeks in subsequent seasons was recorded. A comparison of core (50%) utilization distributions derived from GLS data indicates that Spring, Summer and Autumn breeders have significant proportions of overlapping habitat use, regardless of the time of year. Our results suggest that Kermadec Petrels use the same foraging areas despite seasonal changes in ocean temperatures and chlorophyll productivity. There are informal reports that the species may have a kleptoparasitic foraging strategy, which needs to be explored more fully. GLS studies are now underway to compare foraging locations between Kermadec petrel and other large (400- 600 g), strictly summer or winter breeding Pterodroma petrels in the South Pacific.

**Authors:**

Nicholas Carlile¹, Terence O'Dwyer¹, Luke Halpin²

¹NSW Department of Planning, Industry and Environment, ²Monash University

Year-round breeding of a Pterodroma petrel: how do they do it?

**Abstract:**

Adélie penguins (Pygoscelis adeliae) undergo complete molt shortly after the breeding season. Unlike most penguins, Adélies typically molt on the sea ice rather than on land, with molt lasting up to 3 weeks. Limited mobility and increased metabolic rate during this period create an energetic bottleneck and may be a critical period in the species annual cycle. The timing of molt may also play an important role in determining the start and route of the winter migration. We analyzed data from 120 recovered geolocating dive recorders that were deployed at two colonies on Ross Island, Antarctica. Devices were deployed over 3 winters (2017-2019) on individuals of known-age and breeding history at Cape Crozier (~300,000 breeding pairs) and Cape Royds (~2500 breeding pairs). Adélie penguins do not enter the water during molt so the timing and duration of molt was estimated from the recovered dive logs. We modeled molt timing in relation to several variables including colony, age, sex, breeding status, and breeding outcome. Results indicate molt timing did not differ between colonies but did vary significantly between years, with older individuals and successful breeders molting later. Finally, we examined the relationships between molt timing and the starting location of the winter migration.

**Authors:**

Annie Schmidt¹, Amelie Lescroel¹, Dennis Jongsomjit¹, Megan Elrod¹, Katie Dugger², Virginia Morandini³, Jean Pennycook⁴, David Ainley⁴, Grant Ballard¹

¹Point Blue Conservation Science, ²U.S. Geological Survey, Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries, ³Oregon Cooperative Fish and Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon St, ⁴H.T. Harvey and Associates

Carry-over effects of breeding on molt timing and migration starting location in Adélie penguins

**Abstract:**

Exploratory behavior represents an important way through which individuals collect information about the environment and learn its properties. Individuals may vary in the way they respond to novel stimuli, which may be due to the attributes of these stimuli. The complexity of shapes and colors are important characteristics that can influence the exploratory behavior. Here, we analyzed the exploratory behavior in the Olrog´s Gull Larus atlanticus, by examining how sex and object complexity influence object exploration. Nine adult birds (5 females, 4 males) were caught during the non-breading season in an urban area of the northern coast of Argentina. Birds were identified with leg bands and housed in outdoor aviaries. Each bird was presented with six different geometrical objects in a 15-min trial. Three simple objects had two-dimension geometric shapes without any irregularities. Three complex objects were a combination of two three-dimensional geometric elements with concavities and protruding elements. All objects were of plastic material of three different colors. All individuals approached the objects to less than 10 cm; six of them also contacted at least one object. There were no differences between sexes in the latency to approach the objects, latency at first contact and the total time of exploration (z=0.99, P=0.35; z=0.125, P=0.9; z=0.91, P=0.38; respectively). Twenty-four contact events with the objects were registered, from which 91.7% were made on complex objects, mainly the yellow and red objects. Regarding simple objects, only the yellow one was explored. This is the first study evaluating the explorative behavior of a South American Gull. We suggest that the preference of exploring the complex over the simple objects may indicate that this behavior was guided mainly by the need to extract information about the objects, and not by the potential risk associated to complexity. This first attempt to study the exploratory behavior of the Olrog´s gull is important to understand its response to the new stimuli faced in its environment.

**Authors:**

Melina Castano¹, Laura Biondi¹, Marco Favero¹, Germán García¹

¹Instituto de Investigaciones Marinas y Costeras

Object exploration in seabirds: Olrog's Gull (Larus atlanticus) as case of study

**Abstract:**

Over recent years, accelerometers have proven to be a powerful tool for the identification and quantification of animal behavior. Even though in seabird species this technique has allowed to identify activities such as diving, floating and flying, until now it has never been used to identify and analyze parental food provisioning events. In the present study, we applied the Support Vector Machine (SVM) algorithm to identify food provisioning behaviors from triaxial accelerometer data from breeding Imperial shags (Leucocarbo atriceps). A total of 15 breeding females were equipped with an accelerometer on the head which was programmed to record data at 50 Hz and left on the bird for less than 24 h. In order to label acceleration data, females were filmed during chick feeding and non-feeding events by means of a video camera. Fed chicks were categorized according to age in young and old (less and more than 7 days, respectively). Acceleration features from feeding and non-feeding periods were calculated using a sliding window of 1 s with a 0.98 s overlap. Finally, one SVM was run for each chick category, using a cost value of 1. SVMs correctly classified the feeding and non-feeding events in the 84 and 93% of the cases, for young and old chicks, respectively. However, the specific classification of food provisioning events (recall score), was correct for 79% of young and 95% of old fed chicks. Of the calculated features, those derived from the surge and heave acceleration axes and the pitch angle were the most important for distinguishing feeding from non-feeding behaviors. Our results suggest that accelerometry can be successfully employed to recognize food provisioning events in the Imperial Shag and can be applied in a wider spectrum of seabird species.

**Authors:**

María Monserrat Del Caño¹, Flavio Quintana¹, Giacomo Dell'Omo², Agustina Gómez Laich³

¹Instituto de Biología de Organismos Marinos (IBIOMAR), CONICET, ²Ornis Italica, ³Instituto de Ecología, Genética y Evolución de Buenos Aires (IEGEBA), CONICET

Triaxial accelerometry allows to determine chick feeding events in a marine bird

**Abstract:**

The global population of Leach's Storm-Petrels, the smallest and most abundant breeding seabird species in eastern Canada, has halved during the past 30 years. The largest colonies of these seabirds, located off the east coast of Newfoundland and Labrador, Canada, are experiencing the most dramatic declines. The International Union for the Conservation of Nature (IUCN) lists the species as Vulnerable. Fatal attraction to anthropogenic light is a known risk for seabirds globally and for Leach's Storm-Petrels in particular. Brightly lit oil and gas production platforms intersect the foraging paths of storm-petrels from the largest Newfoundland colonies, and the level of risk posed by attraction to these platforms is poorly understood. Using a GPS tracking dataset (2016 to 2020), we show considerable similarity in foraging trip distance, location, and behaviour among years and between chick and egg incubation periods. Although oil platforms were within the core foraging area of parental storm-petrels, owing to their constraints of nocturnality at the colony and in offshore foraging areas, they tended to transit rapidly past platforms during the day when light attraction is minimized. This research will help focus conservation research on risks outside the breeding season, during migration and winter.

**Authors:**

Sydney Collins¹, April Hedd², David Fifield², David Wilson¹, William Montevecchi¹

¹Memorial University of Newfoundland, ²Environment and Climate Change Canada

Foraging behaviour during the breeding season and associations with offshore oil platforms of Leachs Storm-Petrels

**Abstract:**

Magnetoreception is thought to provide some birds with an accurate compass bearing for orientation during migration, but how widespread the magnetic compass is across taxa remains unknown. Whilst night-migrating songbirds are known to make use of a light-mediated inclination compass in combination with celestial cues to control orientation during migration, evidence for a role of a magnetic compass is much more equivocal across other avian taxa. In Procellariiform seabirds, there is currently no evidence for a role of a magnetoreception during large-scale movements. Studies that have attempted to interfere with magnetoreception in Procellariiformes show that seabirds are able to navigate normally on foraging trips and home successfully from distant locations despite carrying jostling rare earth magnets, free to move unpredictably inside a box attached to the bird's head. However, despite these results from adult Procellariiform seabirds, a magnetic compass remains a possible candidate for movement control that is necessarily inherited, such as first-time migration without adults. We therefore investigated whether the initial orientation of Manx shearwater fledglings is in the direction of the over-wintering grounds (South), and whether this initial orientation might be under the control of magnetic cues, as is known for some songbirds. We used a previously established technique to disorient the magnetic sense in birds by attaching a box with a freely moving strong magnet to the heads of fledgling shearwaters. In order to observe its vanishing bearing, we also loosely attached a tiny LED to its back. Contrary to expectations, birds did not show a consistent southward direction and there was no difference between the magnetic and control treatment. However, the initial orientation of birds was predicted effectively by wind direction. Consequently, we propose that, during their first flight, inexperienced Manx shearwaters are blown off in a direction dictated by the wind.

**Authors:**

Martyna Syposz¹, Ollie Padget¹, Natasha Gillies¹, Joe Wynn¹, Tim Guilford¹

¹University of Oxford

Can a strong magnet disturb the initial orientation of fledgling shearwaters?

**Abstract:**

As seabirds forage for ephemeral and heterogeneously-distributed resources, they should benefit from dynamically adjusting their behaviour to current environmental conditions. Despite this, many species show consistent inter-individual differences in foraging tactics. One potential explanation is that individual differences in personality, and associated pace-of-life variation, means that bolder individuals benefit from investing in 'risky' strategies that afford short-term benefit at the expense of future survival, leading to consistent inter-individual differences in foraging tactics. Bold wandering albatross Diomedea exulans are known to invest preferentially in explorative foraging, thought to represent a high-risk, high-gain strategy, at the expense of patch exploitation, and vice versa for shy birds. Albatross foraging dynamics are highly wind-dependent, yet it is not known whether and how the decisions made by foraging albatross depend on the interaction of personality and wind conditions. Given that bolder birds allocate resources preferentially to current reproduction, we hypothesize that they will maintain high foraging effort irrespective of wind conditions; in contrast, shy birds should minimize energy costs by flying preferentially with prevailing winds. Using a combination of a 10-year, high-resolution GPS dataset, individual measures of boldness, and hidden Markov models, we explore whether personality predicts movement responses of albatross to changes in wind. We show that wind conditions predict propensity to forage or commute between patches in all personality types. Bolder individuals are more likely to transition to commuting behaviour, and shy birds more likely to transition to and maintain foraging, following expectations of the exploration-exploitation trade-off. Our study advances understanding of selection and maintenance of inter-individual behavioural consistency, and individual-level responses to environmental conditions. As changes in wind conditions are already having profound effects on albatross distribution, such information is essential to determine the capacity for populations to deal with future environmental fluctuations.

**Authors:**

Natasha Gillies¹, Henri Weimerskirch², Jack Thorley¹, Tommy Clay³, Lucía Martín López¹, Rocio Joo⁴, Samantha Patrick¹

¹University of Liverpool, ²Centre d'Etudes Biologiques de Chizé, ³University of California, ⁴Department of Wildlife Ecology and Conservation

Examining the interactive effects of boldness and wind conditions on foraging behaviour in the wandering albatross

**Abstract:**

Flight which harvests energy from a wind gradient - dynamic soaring - may allow animals and to move vast distances while expending little energy. Dynamic soaring is, however, difficult to empirically demonstrate. Here, we derive a new metric called horizontal wind effectiveness, a simple and general measure that summarises the effectiveness of a trajectory for harvesting energy from a vertical wind gradient. Using it, we find that Manx Shearwater (Puffinus puffinus), flap-gliding seabirds, consistently harvest energy by dynamic soaring, though not in an optimal manner. They do, however, more closely approach optimality when flying in more favourable conditions - stronger crosswinds. Using GPS, we further find that birds head in more favourable directions when the wind speed is stronger, though only during outbound flight when destination is less constrained. These results are consistent with the idea that small-scale dynamic soaring behaviour impacts large-scale distribution.

**Authors:**

Joe Wynn¹, James Kempton¹

¹University of Oxford

A flap-gliding seabird harvests energy by dynamic soaring, which influences its large-scale distribution

**Abstract:**

Modeling suitable habitats for biodiversity maintenance under changing environments may serve as an important tool for biological conservation purposes. Trindade and Martim Vaz is an oceanic archipelago located ~1.200km from the coast of Brazil, and has been under ecological succession since feral goat eradication, which have devastated its original vegetation. We modeled nesting habitat suitability of a surface-nesting seabird - the Masked Booby Sula dactylatra - at Trindade Is. and predicted its breeding distribution on the island. We mapped 44 active nests of S. dactylatra during the breeding seasons of 2017 and 2019, from October to November at Trindade Is. We fitted nest occurrence points in response to five topographical (Elevation, Slope, Insulation, Aspect and Flow Length) and two vegetation (Succession and Remnant) variables, using an Ensemble Species Distribution Model (ESDM) of four different algorithms: Boosted Regression Trees - GBM, Random Forests - RF, Generalized Linear Models - GLM, and Generalized Additive Model. We evaluated model accuracy based on two metrics: ROC and AUC, and tested for multicollinearity between variables using VIF test. Analyses were performed using the "biomod2" package in software R 3.6.1. Our models showed accuracy above 0.8 in both used metrics (ROC and TSS). Our results indicate areas of very high nesting habitat suitability along the Southwest and Northwest faces of Trindade Is., mostly in elevations varying from 200-400 m (Fig. 1). Elevation and Insulation were the variables that better explained S. dactylatra selection for nesting habitats, while Succession was the one that contributed less (Fig. 2). Since S. dactylatra depends on exposed rocky soils to nest, and that the successional vegetation of Trindade Is., that is already covering most of the Eastern faces, is likely to spread along the Western faces of the island, it is expected to reduce nesting habitat availability for this species in the coming decades.

**Authors:**

Victória Benemann¹, Leonardo Dorneles¹, Rosalinda Montone², Maria Petry¹

¹University of Vale do Rio dos Sinos, ²University of São Paulo

Potential nesting distribution of Masked Boobies (Sula dactylatra) breeding at the remote Trindade Island, western South Atlantic

**Abstract:**

The White-Tailed-Tropicbird (Phaethon lepturus Daudin, 1802) shows a complex life cycle that uses small areas of aggregation for breeding, for example, on remote South Atlantic islands. Long-term surveys focusing in microscale patterns on breeding colonies can provide specific answers about the behavioral ecology of the species. Thus, we focused on studying the occupation and spatial dynamics of P. lepturus. Monthly, from November 2018 to November 2019, White-Tailed-Tropicbirds were monitored by active search on the Chapeu Islet (25M, 564307.35 m E, 9572126.83 m S; 5886.96 m², elevation 9 m a.s.l., Aw Köppen-Geiger CC, limestone pinnacles geological formation), in Fernando de Noronha Archipelago, Brazil. When an active nest was found, we labeled and geo-referenced the site and marked the specimens with CEMAVE bands. We standardized a 23x25 m² grid over the study area and, from the Morisita Index (MI), it was obtained the spatial distribution and density values per month, which was related to the number of active individuals by simple linear regression (R v.3.6.1. software). 434 individuals with local breeding activity were identified during the studied time, 7.8% (n=34) of local fidelity and, of these, 47.0% (n=16) of nest fidelity, with mostly 7-8 months (n=13) time interval to return back to the islet. In all months, happened an aggregate distribution pattern (MI=3.34±0.72; p<0.05) and an inverse relationship between aggregation and the number of active individuals (F=11.29; p<0.05). By comparing natural history data of P. lepturus with other colonies can provide broader understanding of their population dynamics. The singularity of locations as Chapeu Islet provides specific resources to part of those seabirds species life cycle, connecting individuals that use a wider territorial scale.

**Authors:**

Lucas Santos¹, Ricardo Krul², Hellen Rocha¹, Patricia Serafini¹

¹Chico Mendes Institute of Biodiversity Conservation, ²Brazilian Institute for Conservation Medicine (Tríade)

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Year-round breeding of a Pterodroma petrel: how do they do it?

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