A large sea duck of northern rocky coasts that dives for mussels and other shellfish.
Males in breeding plumage are sharply black and white with pale green on the neck; females are brown with fine dark bars.
Groups of Common Eider ducklings and their carers may be approached by females that are not caring for young. In northern Norway, such females fed close to these groups. Compared with solitary feeding females, they spent less of the feeding bout watching their surroundings and more time obtaining food. Their allocation of time differed according to the companions nearby.
Observations in June–July 1989 compared 20 records of females feeding within 10 m of a duckling group with 12 records of females more than 50 m from other females or duckling groups, among other comparisons. Feeding occupied about 70% of the bout near the groups and about 56% when alone. Vigilance accounted for about 20% and 31%, respectively. Non-caring females alternated between raising their heads to look around and lowering them to feed at or near the surface.
An extinction-risk assessment has not been added yet.
NatureScot identifies predation by American mink and foxes and disturbance from dog walkers as threats to nesting Common Eiders in Scotland. Their consumption of shellfish can also bring them into conflict with mussel farmers. Retaining undisturbed breeding places and finding ways to coexist with shellfish farming are regional conservation priorities.