Surf scoter

The surf scoter (Melanitta perspicillata) is a large sea duck native to North America. Adult males are almost entirely black with characteristic white patches on the forehead and the nape and adult females are slightly smaller and browner. Surf scoters breed in Northern Canada and Alaska and winter along the Pacific and Atlantic coasts of North America. Those diving ducks mainly feed on benthic invertebrates, mussels representing an important part of their diet.

In 1750 the English naturalist George Edwards included an illustration and a description of the surf scoter in the third volume of his A Natural History of Uncommon Birds. He used the English name "The great black duck from Hudson's Bay". Edwards based his hand-coloured etching on a preserved specimen that had been brought to London from the Hudson Bay area of Canada by James Isham. When in 1758 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the tenth edition, he placed the surf scoter with the ducks and geese in the genus Anas. Linnaeus included a brief description, coined the binomial name Anas perspicillata and cited Edwards' work. The surf scoter is now one of six species placed in the genus Melanitta that was introduced by the German zoologist Friedrich Boie in 1822. The genus name Melanitta combines the Ancient Greek melas meaning "black" and netta meaning "duck". The specific name is from the Modern Latin perspicillatus meaning "spectacled", in turn derived from perspicere "to see through".

A cladistic analysis based on several morphological characters placed the surf scoter as a monotypic taxon, closest to the white-winged scoter (Melanitta deglandi) and the velvet scoter (Melanitta fusca), which are both sister taxa. These three species form the subgenus Melanitta, distinct from the subgenus Oidemia, which contains the black scoter (Melanitta americana) and the common scoter (Melanitta nigra).

The genus Melanitta is part of the Mergini tribe, a monophyletic group of the Northern Hemisphere. It includes eiders, mergansers, goldeneyes and other sea ducks. This tribe is part of the family Anatidae, along with the swans and geese.

The surf scoter reaches sexual maturity after 3 years. The adult male is on average 1,050 g (2.31 lb) and 48 cm (19 in) in length while the adult female averages about 900 g (2.0 lb) and 44 cm (17 in) in length, making this the smallest species of scoter on average. The surf scoter has a wingspan of 29.9–30.3 in (76–77 cm).

The male is completely velvety black except for white patches on the forehead and the nape. It has a swollen bill, appearing orange at a distance but patterned with white, red and yellow, and a black spot near the base. The female is browner than the male, with a fairly uniform plumage, slightly darker above than below. Indistinct paler patches are present on the cheeks below the eye and sometimes a whitish patch is on the nape, a unique trait among scoters. The bill is black with green or blue colorations The juvenile has a plumage similar to the female, but mainly paler and browner, and the breast and belly are whitish.

The surf scoter is easily distinguishable from other scoters by the white patch on the head of the adult male and its unique bill pattern. Females and immatures have a bulkier bill with a squarish base and a more flattened head profile than other scoters. The black and the white-winged scoters are physically very similar to the surf scoter but in flight, the surf scoter is the only one with completely dark wings.

Like all sea ducks, the surf scoter becomes flightless during the simultaneous molt of its flight feathers. This vulnerable period happens usually in late July through early August and lasts for about four weeks. This wing molt is the start of a complete body or prebasic molt which is completed in the fall producing the next basic or breeding plumage. Before the prebasic molt, many duck species undergo a partial prealternate molt replacing the bright colors of the basic plumage of males by the duller alternate or eclipse plumage but the prealternate molt is believed to be limited or absent such that males appear similar in both basic and alternate plumage, but may have a browner belly and duller or "messier" appearance in summer.