Somateria mollissima; the common eider is of coarse the producer of the eider down. Eider down is harvested in Iceland by specialized eider farmers. Eiders can be found everywhere along the coasts of Iceland. They feed on mussels and other hard shelled-crustaceans like sea-snails, crabs, etc. This food is swallowed as a whole and grinded in the stomach. They also feed to some extent on sea weeds. As a result they can be found much around un-deep shore lines and rocky coasts. Breeding is done in loose colonies in protected areas, often in combination with other birds, like terns. The female does all the breeding and will stay on the nest when it is approached by humans. It is said that one could even caress the birds in that stage. Once the chicks have hatched the female leads them immediately to the water where they are safer - but not safe ! - from full and skua predation. Females with chicks then form larger groups sometimes up to a hundred birds in order to offer better protection against predators. Eiders are both migratory and residents. On Iceland birds from Greenland and Spitzbergen stay during winter times. If you are observing eiders on Iceland see if you can spot a king eider: the females are almost indistinguishable from the common eider. The male king eider is easy to tell apart: it has a red bill and a orange/red shielded forehead which is mainly blue on top and back to the neck. Hybrids are also regularly recorded. It seems that the male king eider will mate with common eider females whilst female king eiders are not seen much during summer on Iceland. A word about the colors of the male plumage. When young male chicks grow up they are first rather dark brown ducks. Over a period of two years they have a number of intermittent phases. Only in spring of the third year do they get the full adult plumage, characterized by an all white back. Birds that have brown spots on their backs and faces are not yet fully adult.