About Melanitta deglandi (Bonaparte, 1850)
Melanitta deglandi, commonly known as the white-winged scoter, is one of three scoter species native to North America, and it is the largest of the scoter species. Female white-winged scoters weigh between 950 and 1,950 g (2.09 to 4.30 lb) and measure 48 to 56 cm (19 to 22 in) in length, with an average weight of 1,180 g (2.60 lb) and average length of 52.3 cm (20.6 in). Males range from 1,360 to 2,128 g (2.998 to 4.691 lb) in weight and 53 to 60 cm (21 to 24 in) in length, averaging 1,380 g (3.04 lb) and 55 cm (22 in). This species has a wingspan of 31.5 in (80 cm). White-winged scoters are defined by their bulky body shape and large bill; the bill is feathered at the gape, which differs from the blocky bill base of the related surf scoter. The white secondary flight feathers that give the species its common name are visible when the bird is in flight, but may be hidden when it is swimming. Adult breeding males are entirely black, with the exception of white feathering around the eye and a white speculum. Their bill is orange and red, with a large black knob at the base. Male white-winged scoters take three years to reach their full definitive adult plumage; second-year males look similar to adult males, but have less prominent eye markings and browner flanks. Females are brownish overall, and are most easily separated from other scoter species by their feathered gape and overall body shape. The facial pattern of female-type birds varies widely: younger individuals have distinct white spots in front of and behind the eye, while adult females may lack these patches and appear entirely chocolate brown during the winter. Juveniles look similar to females, but have more noticeable facial patches and a mottled white belly. Juvenile males have more extensive white coloring on their greater secondary coverts compared to juvenile females, which have little to no white fringing. There are several distinguishing characteristics that separate white-winged scoters from Stejneger's scoters. Male white-winged scoters have browner flanks, dark yellow color across most of the bill, and a less tall bill knob, a profile that is closer to that of the velvet scoter. By contrast, male Stejneger's scoters have a very tall knob at the base of their mostly orange-yellow bill. Females of the two species are very similar, and are best told apart by head shape: white-winged scoters typically have a 'two-stepped' head profile between the bill and the head, while Stejneger's scoters have a long 'Roman nose' profile similar to that of a common eider. Additionally, the feathering along the base of the upper mandible forms a right angle on white-winged scoters, compared to the acute angle seen on Stejneger's scoters. The species' Latin binomial name honors French zoologist Dr. Côme-Damien Degland (1787–1856). White-winged scoters have the largest breeding range of any North American scoter. They primarily breed in boreal forest stretching from Alaska to Western Canada, and are less common further east near Hudson Bay and south toward the Canadian Prairies. They winter further south in temperate zones, on the Great Lakes, the coasts of the northern United States, and the southern coasts of Canada. They form large, tightly packed flocks on appropriate coastal waters, and these flocks tend to take off as a group. This species has been recorded as a vagrant in Europe, including in Scotland, Iceland, Norway, and Ireland.
