Definitions

Black Scoter

Black Scoter

The Black or American Scoter (Melanitta americana) is a large sea duck, 43 to 49 centimeters in length. Together with the Common Scoter M. nigra, it forms the subgenus Oidemia; the two are sometimes considered conspecific, the Black Scoter then being referred to as M. nigra americana. Its French name, used in parts of its Canadian range, is macreuse noire (also meaning "black scoter").

Description

The adult female averages about 980 grams (2.1 lbs.) and 45 cm (18 inches) in length, while the adult male is on average 1100 grams (2.4 lbs.) and 49 cm (19 inches) in length. It is characterised by its bulky shape and large bill. The male is all black with a very bulbous bill which is mostly yellow. The female is a brown bird with pale cheeks, very similar to female Common Scoter. This is America's only black duck, although the female may have some yellow around the nostils. When this bird is in flight, there is a silvery appearance from the underside.

This species can be distinguished from other scoters, apart from Common, by the lack of white anywhere on the drake, and the more extensive pale areas on the female.

Distribution

The Black Scoter breeds in the far north of North America in Labrador and Newfoundland to the southeast Hudson Bay, in Alaska. It also occurs on the Siberian side of the Bering Straits east of the Yana River. It winters further south in temperate zones, on the coasts of the northern USA and Canada, on the Pacific coast south to the San Francisco Bay region and on the Atlantic and Gulf of Mexico coasts, and in Asia as far south as China.

Some birds may over-winter on the Great Lakes. This species is a very rare vagrant to western Europe; only drakes are safely identifiable out of range, so females are likely to be undetected.

Ecology

This species dives for crustaceans and molluscs while migrating or wintering on the sea-coasts, and feeds on insects and their larvae, especially caddisflies, fish eggs and, more rarely, vegetation such as duck weed while nesting on freshwater. It forms large flocks on suitable coastal waters in winter quarters. These are tightly packed, and the birds tend to take off together; in the breeding season they are less social. It has been suggested that in coastal waters this species prefers sheltered embayments, and possibly waters that include some mixed depths.

The lined nest is built on the ground close to the sea, lakes or rivers, in woodland or tundra. 5-7 eggs are laid. Each eggs weighs from 60-74 grams (2-2.6 oz), or 8% of the females body weight. The incubation period may range from 27 to 31 days. Females brood their young extensively for about 3 weeks, after which the still flightless young must fend for themselves.

Footnotes

References

  • Database entry includes justification for why this species is of least concern
  • (1989): Environmental Impact Report for the Pillar Point East Harbor Master Plan. Earth Metrics Inc., San Mateo County Harbor District, February, 1989.
  • (1916): Some unusual records for San Mateo County, California. Abstract in: : Minutes of Cooper Club Meetings. Condor 18(1): 38-40. PDF fulltext DjVu fulltext
  • (2003): Black Scoter (Melanitta nigra). Sea Duck Information Series 2. Version of 2003-OCT-15. PDF fulltext
  • (2001): Birds of North America: A Guide to Field Identification. Golden Publishing.

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