Bird of the Month: White-winged Scoter
By Andy McCormick
Scientific Name: Melanitta fusca
Length 21 in
Wingspan 34 in
Weight: 3.7 lb
AOU Band code WWSC
The White-winged Scoter is one of the world’s three scoters, all of which are seen in winter along the Washington coast. They are all in the genus Melanitta from the Greek melas, black, and netta, a duck. Heinrich Boie (1794-1827) Latinized the Greek word for duck and misspelled it. However, the principle of priority allows the error to stand. Fusca is from the Latin fuscus, dark-colored. The common name derives from the distinctive white wing patches on the secondary flight feathers. The origin of scoter is unknown (Holloway).
In addition to the white wing patches, the male White-winged Scoter has a white crescent-shaped mark trailing out from the eye. Only the front portion of the bill is orange in contrast to the Surf Scoter’s white and orange bill. The head, neck and back are black and the sides are dark brown. The female is dark brown with two faint white marks on the face. These marks are not as distinctive as similar marks on the female Surf Scoter.
White-winged scoters are found in marine waters in winter, but breed in fresh water ponds in the interior of Alaska and Canada in the open boreal forest. White-winged Scoters in the highest abundance are found throughout the Northwest Territories. The nest is a shallow depression on the ground in dense brush often at a distance from water. It is usually lined with plant material and there are 9-10 pale buff or pinkish eggs deposited. The female alone incubates the eggs for about a month (Kaufman). Little is known about the first flight and it could occur anywhere between seven and ten weeks after hatching.
Diving for mollusks is the preferred method of feeding. The White-wings will bring them to the surface and swallow them whole. During breeding both adults and ducklings will eat insects, fish and some plants. In winter the birds fly in small flocks low over the water in long wavering lines, called strings. During the height of migration several thousand can gather on the water as if in a staging area. They are strong flyers and excellent swimmers, but awkward on take-off, when they have to run along the water for a while before lifting off. These ducks are generally silent.
White-winged Scoters have a very strong philopatry, the instinct to return to the same breeding area, and because of it they are vulnerable to changes in habitat. Early records show breeding populations in North Dakota and it is thought that expansion of agricultural use of land and hunting eliminated this portion of the breeding area (Brown et al). Canadian breeding habitat needs further monitoring. Scoters are also vulnerable to oil spills both from direct contact and also due to damage to their foraging habitat in estuaries and bays.