Common Scoter
Melanitta nigra
The common scoter is characterised by its bulky shape and large bill. The male is all black with a bulbous bill which shows some yellow coloration around the nostrils. The female is a brown bird with pale cheeks, very similar to female black scoter. This species can be distinguished from other scoters, apart from black scoter, by the lack of white anywhere on the drake and the more extensive pale areas on the female. The black scoter and common scoter have diagnosably distinct vocalisations.
ID text from Wikipedia, CC BY-SA 4.0
White-winged Scoter
Melanitta deglandi
The white-winged scoter is one of three North American scoter species and the largest species of scoter. Females range from 950 to 1,950 g (2.09 to 4.30 lb) and 48 to 56 cm (19 to 22 in), averaging 1,180 g (2.60 lb) and 52.3 cm (20.6 in). The male ranges from 1,360 to 2,128 g (2.998 to 4.691 lb) and from 53 to 60 cm (21 to 24 in), averaging 1,380 g (3.04 lb) and 55 cm (22 in). The white-winged scoter has a wingspan of 31.5 in (80 cm). This species is characterized by its bulky shape and large bill, which is feathered at the gape unlike the blocky bill base of the surf scoter.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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