Fig. 1: Map of the study area illustrating the high-Arctic distribution of ivory gull (Pagophila eburnea) colonies.

Sampling localities are indicated by the numbers given in Table 1. Small orange dots depict known breeding sites (Gilchrist et al. 2008). Dashed lines show wintering grounds (variable during the winter and among years according to the extension of the sea ice). The background map represents the maximum sea ice extent in July between 1979 and 2013 (light blue) and the sea ice extent in July 2013 (dark blue) (data from the National Snow and Ice Data Centre, Boulder, Colorado; http://nsidc.org/).