Common Eiders (Somateria mollissima) are large sea ducks that breed from Maine north to the Arctic. In winter they form large flocks, often numbering in the thousands!

Common Eiders nest on Eastern Egg Rock but are hard to see there. They hide their nests in the tall grass and sit motionless for weeks while incubating the eggs. They lay 4-5 eggs in a nest made of down plucked from the body of the female.

Eider down used to be very valuable for use in down clothing for humans and was collected from the nests during incubation. Even when the down was taken, the female usually did not abandon the nest. Eider down is no longer collected in Maine, so the birds nest undisturbed.

After 25-30 days of incubation, the chicks hatch and the female leads them off to sea. She often finds other females with chicks and form a group with all the chicks getting to grow and play together.

Pictured at the left are some male Common Eiders in their breeding plumage. They are quite striking and one can see why the females are attracted to them. Unlike most of the seabirds on Eastern Egg Rock, the males do not do very much in raising the young Common Eiders.