Examining the links between environmental variation, foraging behaviour and foraging success in an Arctic seabird

Arctic regions are experiencing increasing variability in inter-annual sea ice dynamics ultimately impacting marine Arctic ecosystems. Arctic-breeding seabirds, such as thick-billed murres (Uria lomvia) are thus likely to be negatively impacted by fluctuating environmental conditions through its influence on prey availability. Additional extrinsic factors (colony size and chick demand) and intrinsic factors (sex) are also likely to impact foraging behaviour and success of murres in combination with environmental conditions. First, we tested the effect of colony size on colony sensitivity to environmental change at two low Arctic colonies of varying sizes, Coats Island, Nunavut and Digges Island, Nunavut across multiple years (2014–2019) in response to broad-scale and fine-scale environmental conditions. Foraging behaviour and foraging success varied in response to environmental variation at both colonies, suggesting flexibility in responding to environmental variability, however, energetic demand was higher at the large colony suggesting increased sensitivity to future environmental change. Second, we investigated the impacts of broad-scale environmental conditions and fine-scale environmental conditions, adult sex, and chick demand on foraging and diving behaviour and foraging success at Coats Island, Nunavut across multiple years (2017–2019). We observed variation in foraging success across strategies suggesting murres at a population level may buffer environmental change through the use of different strategies. Overall, our results suggest warmer oceanic conditions could be benefitting murres breeding at low Arctic sites, especially at a larger colony that has an increased foraging range