Life on the edge: The ivory gull – an endangered specialist in the sea-ice
In recent decades, Arctic sea ice has decreased dramatically in extent and thickness, and many arctic species – including the ivory gull – are threatened by these changes. The ivory gull, being one of few ice-dependent seabirds, is endangered and red listed in all countries where it breeds.
An understanding of how ice-edges and ice concentration influence the distribution of the ivory gulls is a prerequisite to the implementation of adequate conservation strategies for the species. From 2007 to 2013, the movements of 104 ivory gulls caught in Canada, Greenland, Svalbard-Norway and Russia, were monitored using satellite transmitters.
Seventy five percent of the ivory gulls’ recorded positions are within 100 km of the ice-edge. The distribution relative to sea ice concentration varied through the year. From May to September, 80 % of the positions were on relatively highly concentrated sea ice. During migration and winter season, the frequency dropped to less than 50 %. The best model to explain the distance of the birds from the ice-edge included the ice concentration within approximately 10 km, the month and the distance to the breeding colony.
Read the article:
Because of the ivory gull’s strong affinity to the sea ice and the productive ice edge, it is unlikely that the situation for this species will improve in the future, taking into account the overall decrease of sea ice. Less sea ice also opens up areas accessible for human activities, which increases the threat of pollution and disturbances in areas especially important for the ivory gull.
Contact person: Hallvard Strøm, Norwegian Polar Institute
Photo: Hallvard Strøm