The black scoter, or American scoter, Melanitta americana, is a robust sea duck with a distinctive appearance. Males are entirely black with a notably bulbous, mostly yellow bill, while females are brown with paler cheeks, resembling the female common scoter. Adult males typically measure 49 cm (19 in) in length and weigh around 1,100 g (2.4 lb), whereas females are slightly smaller at 45 cm (18 in) and 980 g (2.16 lb).
To identify the black scoter, look for the absence of white on the male and the more extensive pale areas on the female. The male's unique yellow bill is a key distinguishing feature. When observing these birds, note their size and shape, as well as the characteristic bill of the males, to differentiate them from similar species.
The black scoter breeds in the northern reaches of North America, favoring the regions of Labrador, Newfoundland, and around Hudson Bay. It also nests on the Siberian side of the Bering Straits. During winter, it migrates to temperate coastal areas, including the northern USA and Canada, the Pacific coast down to the San Francisco Bay area, and the Atlantic and Gulf of Mexico coasts.
This species has a broad range, breeding in the far north and wintering in more temperate zones. It can be found as far south as China in Asia. Some individuals may over-winter on the Great Lakes. The black scoter is a rare visitor to western Europe.
Black scoters are sociable in winter, forming large, tightly packed flocks on coastal waters. They are less social during the breeding season. The species is known for diving to forage for crustaceans and molluscs. Males have a distinctive downward head movement when stretching their wings.
The vocalizations of the black scoter are distinct from those of the common scoter, with diagnosable differences that can aid in identification.
Breeding occurs later than most North American ducks. Pairs form in late winter or spring, with nests built on the ground near water. Females lay 5β7 eggs, with each egg weighing 8% of her body weight. Incubation lasts 27 to 31 days, and females brood their young for about 3 weeks before the flightless young are left to fend for themselves.
The black scoter can be confused with the common scoter, but the lack of white on the male black scoter and the more extensive pale areas on the female help distinguish the two.
While migrating or wintering, black scoters dive for crustaceans and molluscs. During the nesting period, they consume insects, larvae, fish eggs, and occasionally vegetation.
The black scoter is currently listed as Near Threatened by the IUCN, indicating that it faces threats that could lead to its vulnerability in the near future.