| Biology: |
Coastal (Ref. 356). A boreal species (Ref. 95075). Winters in the north Pacific (Ref. 356). Also, in northern Norway where it is sympatrically associated with Common Eiders, Somateria mollissima, through feeding depth segregation; diving to >20 m, in areas dominated by cobble. Diet studies reflect its deep-water feeding habit, preferring low energetic food such as echinoderms. Possibly one of the most deep-diving species of sea ducks; with flocks observed diving to depths of 40 m (Ref. 60129). Displays surface-diving and head-dipping (Ref. 356). Generally diurnal feeders. Often feed in densely packed rafts of up to about 70 individuals, with highly synchronized diving; occasionally feeding singly or in loose flocks with unsynchronized diving. At sea, feed primarily on benthos, specifically molluscs, crustaceans and echinoderms. Principal moulting area in the eastern Canadian Arctic is in the Disko Bay region, central West Greenland, with about 100,000 birds congregating in autumn. Active during the day, resting at mid-day and during the night offshore on the deepest waters of the fjords. Generally shy birds, particularly during molting (Ref. 95257). |