Diet of moulting King Eiders Somateria spectabilis at Disko Island, West Greenland

During the autumns of 1990-1992, 109 moulting King Eiders Somateria spectabilis were collected at Disko Island, West Greenland, for analysis of stomach contents . All collected birds had food in their stomachs . The mean number of prey items per stomach was 11 .1 . Moulting King Eiders had a varied diet (minimum 41 prey species), with mollusks comprising the bulk of the food. Bivalves of 21-40 mm length occurred more frequently in the stomachs than did other size categories of bivalves . There was no marked difference in food composition between sex and age classes of eiders, and the diet varied only slightly between the study years. Female eiders depend strongly on a high prey density owing to their late arrival in the area and shorter day lengths