United States

**Abstract:**

Locating ample food for self-maintenance and reproduction is a key challenge for wild animals, with consequences for individual fitness and population processes. The methods that individuals employ to locate food are partially shaped by environmental conditions that often vary spatio-temporally. In avian species, rain can affect behaviour, impairing senses and increasing energetic costs. However, the consequences of rain on movement behaviour are largely unexplored. We investigated the influence of rainfall on the foraging behaviour of a tropical seabird, the magnificent frigatebird Fregata magnificens. They are highly efficient flyers that can spend long time aloft, tracking environmental conditions to find foraging opportunities. Uniquely among seabirds, frigatebirds lack feather waterproofing and cannot dive nor perch on the water surface. Their foraging behaviour should thus be highly sensitive to the effects of rainfall. We tracked the foraging movements of 33 chick-rearing adults from a population in the Cayman Islands, central Caribbean. We firstly investigated whether foraging individuals avoided areas with high rainfall. We then assessed the broad-scale effects of rainfall on trip characteristics. Finally, we investigated fine-scale behavioural responses to local variation in rainfall, using Hidden Markov models that accounted for possible confounding effects of wind speed. Frigatebirds did not avoid areas with high rainfall during foraging trips, nor did rainfall influence trip characteristics. However, rainfall decreased time devoted to foraging-related activities and increased time spent perching. Moreover, it affected flight mode, inducing birds to fly slower and at lower altitudes. Wind speed, which was not correlated with rainfall, had a distinct effect, with strong winds affecting night-time behaviours by decreasing time spent perching. Our results indicate that rainfall does not affect the spatial distribution of foraging frigatebirds but does alter fine-scale foraging behaviour through reducing flight activity. Frigatebirds appear to cope with frequent rainfall events in tropical oceans by reducing their activity levels. We suggest that ongoing environmental changes in this region, through increasing storm frequency and intensity, has the potential to impair foraging and indirectly affect the fitness of these apex predators.

**Authors:**

Federico De Pascalis¹, Rhiannon Austin², Jonathan Green², John Arnould³, Simona Imperio⁴, Jane Haakonsson⁵, Jacopo Cecere⁴, Diego Rubolini¹

¹University of Milan, ²University of Liverpool, ³Deakin University, ⁴ISPRA, ⁵Government of the Cayman Islands

3rd World Seabird Conference

Storm riders or hiders: rainfall alters foraging activity in a tropical seabird

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!

symposium

**Abstract:**

Gulls are highly flexible in their response to dynamic atmospheric conditions across a range of terrestrial and marine environments. With their generalist diets gulls are also able to forage in many human-impacted environments such as urban and agricultural areas or fisheries, which may then render them vulnerable to changes in human behaviour. Increasingly gulls are foraging inland, which offers a very different atmospheric landscape to the marine and coastal environments they are traditionally associated with. Sources of uplift used in soaring flight, such as thermals and orographic lift, are generally less common at sea, which could mean there is a greater potential of energetic savings for gulls that choose to fly inland. However much remains unknown regarding the degree to which gulls can respond to atmospheric dynamics at varying scales over sea or land, and the degree to which it affects their foraging decisions and flight energetics. We analyse the movements of lesser black-backed gulls (Larus fuscus) in relation to atmospheric uplift over sea and land, using high-resolution GPS and accelerometer measurements alongside advanced atmospheric modelling methods. We demonstrate some of the different ways in which sources of uplift such as thermal uplift are used by gulls to save energy in flight, and how flight behaviour differs between land and sea as a result of the atmospheric environment. Gulls spend far more time soaring over land than at sea , likely due to increased surface heating over land and more orographic lift produced by landscape heterogeneity. Nevertheless, certain scenarios at sea can generate suitable soaring conditions which gulls take advantage of. Overall we show how opportunistic use of atmospheric conditions helps to facilitate soaring flight, and how the differing atmospheric conditions over land and over sea influence the energetic cost of flight.

**Authors:**

Elspeth Sage¹, Willem Bouten¹, Kees Camphuysen², Judy Shamoun-Baranes¹

¹University of Amsterdam, ²Royal Netherlands Institute for Sea Research

Fine scale flight behaviour of gulls in response to dynamic atmospheric conditions over land and sea

**Abstract:**

A significant portion of the global population of Grey-headed Albatrosses (Thalassarche chrysostoma; Endangered) breed on sub-Antarctic Marion Island (46°53′ S 37°44′ E). Although most pairs breed on coastal cliffs, ca 4000 pairs breed on an inland ridge. These birds occasionally crash into the valley below the ridge, with birds either dying on impact or as a result of starvation if they are unable to take off again due to injury or absence of suitable wind conditions. We determined the number of birds affected and their distribution within the valley by counting carcasses and stranded birds in the valley on a regular basis between 2017 and 2019. Of the carcasses recovered, almost half are juveniles presumably killed during their first flight, with 41±23 killed per year (2.4% of chicks fledged each year). On average 45±21 adult carcasses were recovered each year, which represents 0.6% of the annual breeding population along the ridge, making wind-induced collision mortality a significant cause of death for a species that has a natural mortality rate of only ca 4% per year. Wind measurements taken in the area show this region is associated with high turbulence and gustiness. Simulations of wind around the ridge, using computational fluid dynamics (CFD), show that the flow over the area with the highest crash density is characterised by a concentrated down-draft under specific wind conditions. Although albatrosses are efficient at detecting and exploiting wind gradients at sea, operating near ground can be extremely risky, as these birds lack the power needed to respond to strong turbulence and downdrafts that are commonly associated with steep terrain. Crashes represent a source of mortality that is rarely considered. Further studies are needed to ascertain which wind conditions are most risky, whether they reduce the risk of crashing by avoiding taking off or landing under these conditions, and how the birds might be impacted by changing wind regimes. Simulating changes in wind speed and direction would aid in understanding the potential effects of wind as a factor of climate change on the local wind patterns and, subsequently, the population dynamics of Grey-headed Albatrosses breeding on Marion Island.

**Authors:**

Janine Schoombie¹, Stefan Schoombie², Kyle Goddard¹, Emily Shepard³, Peter Ryan⁴, Lelanie Smith¹, Ken Craig¹

¹University of Pretoria, ²Nelson Mandela Metropolitan University, ³Swansea University, ⁴FitzPatric Institute of African Ornithology, University of Cape Town

Wind-induced collision mortality in Grey-headed Albatrosses breeding on Marion Island

**Abstract:**

Technological advances in biologging in recent years have opened several new avenues to study the at-sea behaviour of seabirds. The efficiency and size of these loggers have been improved to such an extent that fine-scale behavioural data can be recorded for extended periods. This is particularly useful when studying the at-sea behaviour of far-ranging Procellariiformes, a task that is often logistically challenging. We used a combination of biologgers (GPS, video camera and inertial measurement units [IMUs]) to study the flight behaviour of several procellariiforms breeding on sub-Antarctic Islands in the southern Indian and Atlantic Oceans, in varying wind conditions. The IMUs (including tri-axial accelerometers and magnetometers) allowed us to infer fine-scale (40 Hz) movement patterns while the video cameras were used to ground-truth the IMUs and to extract bank angles from recorded flights. Dynamic soaring was identified through sinusoidal curves in magnetometer axes (independent of acceleration), while individual flaps were identified from the heave axis of the accelerometer. GPS loggers provided hourly location estimates, which were used to determine local wind conditions from satellite data. Albatrosses displayed dynamic soaring during most flights, with the duration of cycles decreasing and bank angles increasing with increasing wind speeds. By coupling flapping and roll angles we show that flapping, on occasion, occur at the upper turn of the dynamic soaring cycle, a period previous thought devoid of flaps. These results also suggest possible sexual differences, where males seem to flap more often than females and limit their take-offs to favourable wind conditions. This study shows how multiple fine-scale loggers can be used to gain insights on how seabirds of varying body sizes are able to travel vast distances in the dynamic Southern Ocean environment.

**Authors:**

Stefan Schoombie¹, Rory Wilson², Peter Ryan¹

¹FitzPatrick Institute of African Ornithology, ²Swansea University

Fine-scale flight: the effect of wind on flight patterns of dynamic soaring seabirds

**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:**

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

Brown pelicans as a model of partial migration in nearshore seabirds

**Abstract:**

Polar systems of avian migration remain unpredictable. Here we report on three related predatory seabird species that divided across four oceans following sympatric breeding at a central Canadian high Arctic nesting location. Using telemetry we tracked Pomarine Jaeger (Stercorarius pomarinus; POJA, n=1) across the Arctic Ocean to the western Pacific Ocean; Parasitic Jaeger (S. parasiticus; PAJA, n=4) to the western Atlantic Ocean, and Long-tailed Jaeger (S. longicaudus; LTJA, n=2) to the eastern Atlantic Ocean and western Indian Ocean. We also report on extensive nomadic movements over ocean during the post-breeding period (19,002 km) and over land during the pre-breeding period (5,578 km) by Pomarine Jaeger, an irruptive species whose full migrations have been a mystery. Understanding the routes and migratory divides of birds nesting in the Arctic region has implications for understanding both the glacial refugia of the past and the Anthropocene-driven changes in the future.

**Authors:**

Autumn-Lynn Harrison¹, Paul Woodard², Mark Mallory³, Jennie Rausch²

¹Smithsonian Conservation Biology Institute, ²Canadian Wildlife Service, ECCC, ³Acadia University

Sympatrically-breeding congeneric seabirds (Stercorarius spp.) from Arctic Canada travel to four oceans

**Abstract:**

Feathers play an important role in many aspects of avian ecology, including sexual selection, thermoregulation and flight. However, several external stressors can negatively impact plumage condition. Birds preen their feathers to maintain feather integrity throughout the year. For seabirds, preening is especially important to ensure waterproofing of the plumage. However, due to the difficulty of observing seabirds at sea, little is known of the time and energy expended in preening and how this may impact other activities in these species. In the present study, bird-borne video and tri-axial accelerometer data loggers were used to investigate preening in Australasian Gannets (Morus serrator) from two colonies in south-eastern Australia. Gannets spend a substantial proportion of their time at sea preening (25.5 ± 1.7%). No significant differences in preening activity were observed between the 3 years of study or between colonies. Average Vectorial Dynamic Body Acceleration (VeDBA, a proxy for energy expenditure) was significantly higher during preening (0.34 ± 0.02 g) than resting (0.25 ± 0.02 g), but less than for flying or foraging. These results highlight the importance of preening in terms of time and energy in this species. Furthermore, a positive relationship between the number of dives and at-sea preening suggests a negative impact of diving on plumage integrity and, thus, a potential additional time and energy constraint during periods of reduced food availability.

**Authors:**

Louarn Fauchet¹, Thomas Cansse¹, John P.Y. Arnould¹

¹Deakin University

The importance of preening behaviour in the at-sea time budget of Australasian gannets

**Abstract:**

Long-term monitoring data of seabirds have revealed the annual trend of mercury exposure in seabirds that are known to play a role of biovectors transporting methylmercury from the ocean to the land. However, it is unclear how wintering distribution and habitat affect the efficacy of seabirds as mercury biovectors. To address this issue, we tested whether seabirds that fly through and hence feed in regions of high [Hg] have a higher biovectors capability, and whether their at-sea behavior is more heavily impacted. To time exposure, we exploited the differential turnover rate of different bird tissues in storing Hg until they reach their colony in the Spring; to assess Hg biotransport, we sampled terrestrial plants at their colony; to assess wintering behavior, we monitored stable isotopes of nitrogen (δ15N; trophic position) and equipped birds with data loggers (geolocation and activity). By contrasting two areas on both sides of the North Pacific of high (Japan; n = 10) and low (Alaska; n = 11) Hg emissions and using the Rhinoceros auklet as a model species, we show that all sampled individuals have high [Hg] (0.3-11.4 μg g-1) that are ultimately deposited at their colony via feces. While exposure levels of auklet tissues were associated with environmental contamination levels during wintering, at-sea behavior was transient Alaskan birds, but long-lasting in Japanese birds. These results not only indicate that seabirds can be used as a tracer of large-scale Hg emission rates, but also that seabirds may suffer long-term behavioral changes when subjected to higher Hg during winter.

**Authors:**

Akiko Shoji¹, Kyle Elliott², Yutaka Watanuki³, Stéphane Aris-Brosou¹, Shannon Wheeler², Scott Hatch⁴

¹University of Ottawa, ²McGill University, ³Hokkaido University, ⁴Institute for Seabird Research and Conservation

Mercury biotransport by auklets: two-colony comparison

**Abstract:**

The remoteness of islands allowed for the evolution and maintenance of rich and endemic biodiversity, isolated from many pressures including anthropogenic ones. The increasing use of, and visitation to, these isolated territories by people (especially tourists) enables the investigation of how biodiversity reacts to novel pressures. Indeed, humans can have an indirect effect associated with their mere presence as wildlife responds to people as if they are predators. Seabirds for example rely on isolated, "low disturbance" areas to reproduce. They are one of the most threatened animal groups at a global scale and their risk of extinction is increasing faster than any other group of birds. We measured flight-initiation distances (FIDs) and monitored the breeding status of six seabird species breeding on tree islets of Coral Sea. We then developped a spatiality explicit sensitivity index considering both classical diversity metrics (species abundance and richness) and this behavioural metric of birds sensivity to human disturbance. Our prospective dataset first shows that seabirds sensivity to human disturbances varies between species and along their reproductive cycle. Shorter FID recorded during the most vulnerable stages of the reproduction, ie egg laying and chicks rearing, support the hypothesis of a 'sit and defend' strategy. Thereby, nest defence would likely be a better predictor of birds behavioural response than predation avoidance during critical reprodutive states. On the other hand, our spatially explicit index provides an innovative and promising sensibity metric by including seabirds behavioural responses to disturbances. In island contexts facing increasing pressures from human visitations and tourism, we believe that this index may address the need for conservation planning tools.

**Authors:**

Martin THIBAULT¹, Mike Weston², Andreas Ravache¹, Eric Vidal¹, Thomas Bouyard³

¹ENTROPIE (IRD), ²Deakin University, ³IRD

Flight-initiation response as a promising conservation planning tool on remote islets

**Abstract:**

In seabirds chick growth rates at early period would be determined survival of chicks after fledging. So, it is expected that parents with greater efforts provide more foods their chicks to be faster grow, especially at the early period. To determine this hypotheses we measured parental daily energy expenditure (DEE) of rhinoceros auklets Cerorhinca monocerata as parental effort and chick growth rates at early breeding stage (day of 5-20) at Teuri Island, Hokkaido, Japan in late May - July in 2018 and 2019. We measured daily energy expenditure (DEE) of parental birds at early chick stage (day of 14-19) using by doubly labelled water method and body mass of chicks daily until fledging. Chicks being greater grow at the early stage had larger body mass at fledging. However, there was no relationship between parental DEE and chick growth rates at the early period, and our hypotheses was not supported from the study. This result suggests that there is large individual variation in parental foraging efficiency; some parents could provide larger foods with greater DEE and others less foods with similar DEE to the former.

**Authors:**

Nao Nagatani¹, Masaki Shirai², Jumpei Okado¹, Yasuaki Niizuma³

¹Graduate school of Fisheries Sciences, Hokkaido University, ²Central Resaerch Institute of Electric Power Industry, ³Laboratory of Environmental Zoology, Meijo University

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