Influence of sea-ice-related features and anthropogenic subsidies on the foraging behaviour of a high-Arctic seabird, the ivory gull (Pagophila eburnea).

The Arctic region is currently experiencing major modifications in sea ice extent and phenology due to global climate and anthropogenic changes. As Arctic marine ecosystems rely greatly on the presence of sea ice and its seasonal dynamics, these changes could have major impacts on Arctic biota. The ivory gull (Pagophila eburnea) is an endemic Arctic seabird whose populations are declining in Canada and Svalbard. Its affinity for sea ice makes it a good sentinel species of current changes in the high Arctic. We explored the influence of sea-ice-related features and anthropogenic subsidies on the foraging behaviour of ivory gulls during the breeding season. To this end, we analysed the movement of adult ivory gulls in north-east Greenland. We confirmed that ivory gulls use a dual foraging strategy, with birds faithful to their foraging areas at short distances from the colony, but used individual-specific areas during long-distance foraging trips. We highlight that ivory gulls are spatially specialised individuals within a generalist species. We demonstrated that human settlements attracted foraging birds, which shows that human presence in such a remote place may influence the seabird behaviour. Finally, by combining hidden Markov models and resource selection functions, we showed that ivory gulls selected highly concentrated sea ice for foraging during the breeding season. Our study provides key information on the use of space and foraging strategies of ivory gulls during the breeding season, and more broadly, how Arctic seabirds use ice features. [ABSTRACT FROM AUTHOR]