**Abstract:**

Presently, inter-annual variability in sea ice dynamics is increasing in Arctic regions. Sea ice dynamics, such as the timing of ice-melt and sea ice extent, highly influence trophic dynamics in marine Arctic systems, leading to changes in the abundance and distribution of fish and invertebrates. Thick-billed murres (Uria lomvia) - a pursuit diving seabird that preys upon pelagic fish, benthic fish, and invertebrates - are thus expected to be negatively impacted by shifts in marine Arctic community structure. As such foraging behaviour, including the decision to balance self-feeding and chick-provisioning, will be influenced by environmental conditions, and mediated by either adult or chick body condition. In a low ice year, associated with reduced food availability, adults may choose to maximize self-feeding to maintain adult condition, while reducing chick provisioning at the cost of chick condition. Alternatively, adults may maintain or increase chick-provisioning to maximize chick condition, while reducing self-feeding at the cost of adult condition. To investigate the impact of environmental conditions on resource allocation decisions in this system we fitted adult murres with GPS accelerometers during the incubation and chick-rearing periods at Coats Island, Nunavut, Canada in 2018 and 2019. To assess the success of foraging trips for adult energetic condition we blood sampled murres before/after GPS deployments to measure energetic hormones (corticosterone), metabolites (non-esterified fatty acids, beta-hydroxybutyrate, and triglycerides), and stable isotopes (δ13C and δ15N). To assess the success of foraging trips for chick energetic condition, we conducted feeding watches to identify prey types and chick-provisioning rates. By determining how variation in environmental conditions impacts resource allocation decisions, we can predict how breeding success and ultimately fitness will be impacted in rapidly changing Arctic ecosystems.

**Authors:**

Alyssa Eby¹, Allison Patterson², Kyle Elliott², H. Grant Gilchrist³, Oliver Love¹

¹University of Windsor, ²McGill University, ³Environment and Climate Change Canada

Resource allocation of a deep-diving Arctic seabird, the thick-billed murre (Uria lomvia), in response to sea-ice variation during the chick-rearing period

**Abstract:**

Overall, sea ice extent is declining in Arctic systems. However, variability in inter-annual sea ice extent is increasing. Sea ice dynamics greatly influence trophic dynamics in marine systems, where changes in sea ice extent and timing of ice melt can affect the abundance and distribution of fish and invertebrate species. Higher trophic level Arctic breeding species, such as thick-billed murres (Uria lomvia), could be negatively affected by changes in sea ice extent via impacts on foraging behaviour, resulting in greater foraging effort in low ice years. Colony size has also been shown to influence foraging behaviour, where individuals at larger colonies must forage at greater distances as resources surrounding the colony are depleted at a faster rate (Storer-Ashmole's halo hypothesis). As such, the impacts of ice extent on foraging effort are likely to have colony-specific impacts on the energetic profitability of foraging and therefore breeding success. To quantify the impact of changing environmental conditions on the foraging behaviour and payoffs of murres at different sized colonies we deployed GPS units and GPS accelerometers at two colonies in the low Arctic, Coats Island, Nunavut (30 000 breeding pairs; sampled in 2018, and 2019) and Digges Island, Nunavut (400 000 breeding pairs; sampled in 2014, 2015, and 2016). We measured sea ice extent throughout the breeding period and collected blood samples before and after GPS deployments to measure energetic hormones (corticosterone) and energetic metabolites (non-esterified fatty acids, beta-hydroxybutyrate, and triglycerides) as proxies for foraging success of trips. Quantifying the complex impacts of the interaction between colony size and ice extent on foraging success and foraging flexibility will give us predictive insight into which breeding colonies may have a greater capacity of withstanding Arctic climate change.

**Authors:**

Alyssa Eby¹, Allison Patterson², Graham Sorenson¹, Thomas Lazarus², Kyle Elliott², H. Grant Gilchrist³, Oliver Love¹

¹University of Windsor, ²McGill University, ³Environment and Climate Change Canada

Comparing foraging success of thick-billed murres (Uria lomvia) from two colonies in the Canadian Arctic in response to environmental conditions

**Session Replay:** [Click here](https://zoom.us/rec/share/sDvAiaFdq5qBsfnKlC4ZQcmCLLo1oO2yvz0rFi2BjFg5JfzjzHCHqcpjUfA9594.3bgkF-G95Clramln?startTime=1633435108000)<br><br>

<i>**Session Chair: **Ruth Dunn</i><br><br> 
**Session Description:**<br>Recent assessments of species and ecosystem responses to environmental change have highlighted an urgent need to better understand the mechanistic links between the patterns of change, individual responses, and population processes. Without this link our ability to assess the vulnerability of seabird populations to environmental stressors, such as contaminants, disease, overfishing and re-organization of trophic food webs, and to establish effective management programs is severely limited. Conservation physiology is a rapidly growing field, and there is considerable scope to apply its recent developments to seabird conservation issues. The 21st century has seen the development of new metabolic, endocrine and molecular approaches that allow detailed quantification of physiological traits in free-living birds, bringing the study of physiology out of the laboratory and into the wild. For example, recent work measuring fine-scale energetics has illustrated how many applied problems in conservation boil down to issues of energy intake or energy output. Endocrine and molecular markers of exposure to stressful events during different stages of the annual cycle provide insight into physiological carry-over effects on patterns of survival and reproduction. Developments in the field of historical ecophysiology allow us to examine individual seabird responses to climate change on a millennial scale. Such approaches have the potential to identify when, where, and why seabird populations are vulnerable before catastrophe strikes, thus vastly improving our conservation efforts. This symposium will focus on the potential of physiology to provide mechanistic answers to applied conservation questions from marine reserve design, to pollution monitoring, to seabirds as indicators of climate change responses.<br>

Symposium 1 - Conservation physiology in seabirds: Understanding mechanisms, causes and consequences in a changing world I

symposium

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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<iframe width="560" height="315" src="https://www.youtube.com/embed/JOLEP6uTMuc" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>



3rd World Seabird Conference

Join us for four days of science, networking and virtual engagement with delegates from around the world!

**Session Replay:** [Click here](https://zoom.us/rec/share/MU0WTdY93-E3wV88fhymaYRmdNN1xkILGmPBC7urfMHrzKruWkxiyyWEt9Ss5x8i.GkdTMdtR--FjZnwo?startTime=1633615474000)<br><br>

<i>**Session Chair: **Christophe Barbraud</i><br><br> 
**Session Description:**<br>Sea-ice provides a unique ecosystem for seabirds as a breeding platform and as a major foraging habitat. As the extent and volume of global sea ice continues to decline, the importance of pagophilia will be an important component of the resilience of polar wildlife to change. The proposed symposium will make an overview of the effects of sea ice characteristics, variability and trends on the foraging ecology, demography and population dynamics of seabirds, at scales ranging from days to decades. A number of important long-term datasets (up to 50 years) will be presented, and data from long-term studies of behaviour and demography will be combined to assess mechanisms linking ice with population-level processes. The session will be organized to represent increasing spatio-temporal scales of study: from primary productivity and ice dynamics, to the behaviour and demography of seabirds. The session will gather experts from both poles into a common framework for examination of ice-obligate species.<br>

Alyssa Eby

2

2

SHORT BIO

Presentations

Resource allocation of a deep-diving Arctic seabird, the thick-billed murre (Uria lomvia), in response to sea-ice variation during the chick-rearing period

Comparing foraging success of thick-billed murres (Uria lomvia) from two colonies in the Canadian Arctic in response to environmental conditions

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