Somateria mollissima
Order Anseriformes
Family Anatidae
Subfamily Anatinae
Other names: American Eider, Sea Duck
♂ Adult male.— Top of head black, divided by a white stripe; rest of head white, tinged on the sides and back with green; neck, upper breast, and most of back white; middle of lower back, wings, tail, and belly black; bill, legs, and feet olive-green.
♀ Adult female and Immature.— Top of head blackish; rest of plumage dark buffy-brown, lightest on throat and neck, barred everywhere with black.
Nest, on the ground, often under a bush.
Eggs, olive-green.
The American Eider is a common winter visitant off the coast of New England, arriving in October, and returning in April. It is rare south of Massachusetts. It is a rare summer resident on some of the rocky islands of the Maine coast, from Isle au Haut eastward. Great flocks of eiders collect in the shoal water off Cape Cod, Nantucket, and Martha’s Vineyard, spending the night at sea, and flying in each morning to some ledge of rocks, where they find the mussels on which they feed. These they obtain by diving through the breakers. The Eider is rarely seen in the inner bays and harbors; in fact it is known among the fishermen as the “Sea Duck.”
The adult male is a very striking bird, the black crown and belly contrasting with the white breast and back. The female may be distinguished from other brown ducks by her size and the presence in the flock of black and white males. In April as the flocks fly north, the males and females alternate irregularly and fly in long lines low over the water. (See Mackay, “ Auk,” vol. vii. pp. 315-319.)
NOTE.- The King Eider (Somateria spectabilis) is a rare winter visitant to the coast of New England, occasionally common off the coast of Maine. The adult male may be distinguished from the [Common Eider] by the top of the head, which is a delicate lavender instead of black, and by the cheeks, which are sea-green instead of white.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)