Histrionicus histrionicus
Order Anseriformes
Family Anatidae
Subfamily Anatinae
♂ Adult male.— General color leaden blue, changing into blue-black on lower back, and bluish-gray on belly; triangular crescent-shaped spot in front of the eye, a round spot near the ears, a narrow collar around lower part of neck, a broad bar across breast, and other markings on wing and breast white; under side of neck and bar on side of breast, centre of forehead, crown, and hind neck black; sides bright reddish-brown; bill and feet slate.
♀ Adult female.— Head and neck grayish-brown; a white spot back of the ear; sides of head tinged with white; sides grayish-brown; bill and feet slate.
The Harlequin Duck is a rare but regular winter visitant on the eastern half of the coast of Maine, frequenting rocky ledges and islets well out at sea. It may be distinguished from other ducks by “the combination of small size, dark color, and buoyancy, in air and water” (Norton, “ Auk,” vol. xiii. pp. 229–234). The female may be distinguished from the female Old-squaw [Long-tailed Duck] by the color of the belly, which is grayish dusky instead of pure white.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)