Editing Greater scaup (section)

==Description==
The adult greater scaup is {{convert|39|–|56|cm|abbr=on}} long with a {{convert|71|–|84|cm|in|abbr=on}} wingspan and a weight of {{convert|726|-|1360|g|lb|abbr=on}}. It has a light blue bill with a small black [[Beak#Nail|nail]] on the tip, yellow eyes, and is 20% heavier and 10% longer than the closely related lesser scaup.<ref name=Birdweb/> The male has a dark head with a green to purple sheen, a black breast, a light back, a black tail, and a white underside. The drake or male is larger and has a more rounded head than the female. The drake's belly and flanks are a bright white. Its neck, breast, and tail feathers are glossy black, while its lower flanks are [[vermiculated]] grey. The upper wing has a white stripe starting as the [[speculum feathers|speculum]] and extending along the flight feathers to the wingtip. Legs and feet of both sexes are grey.

The adult female has a brown body and head, with white wing markings similar to those of the male but slightly duller. It has a white band and brown oval shaped patches at the base of the bill, which is a slightly duller shade of blue than the drake's.<ref name="DucksUnlimited" /> Juvenile greater scaup look similar to adult females. The drake's [[Plumage#Eclipse plumage|eclipse plumage]] looks similar to its breeding plumage, except the pale parts of the plumage are a buffy grey.<ref name="enature" />

Distinguishing greater from lesser scaups can be difficult in the field. The head of the greater tends to be more rounded, and the white wing stripe is more extensive. The bill is also tends to be larger and wider, with a slightly larger black nail at the tip. The North American subspecies ''A. m. nearctica'' typically has a higher forehead and reduced white on the wings, intermediate between the European ''A. m. marila'' and Lesser Scaup.<ref name="Birdweb" />