Greater Scaup

The adult greater scaup is 39–56 cm (15–22 in) long with a 71–84 cm (28–33 in) wingspan and a body mass of 726–1,360 g (1.601–2.998 lb). It has a blue bill and yellow eyes and is 20% heavier and 10% longer than the closely related lesser scaup. The male has a dark head with a green sheen, a black breast, a light back, a black tail, and a white underside. The drake or male greater scaup 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 a glossy black, while its lower flanks are vermiculated gray. The upper wing has a white stripe starting as the speculum and extending along the flight feathers to the wingtip. Legs and feet of both sexes are gray. 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. Juvenile greater scaup look similar to adult females. The greater scaup drake's eclipse plumage looks similar to its breeding plumage, except the pale parts of the plumage are a buffy gray. 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.

Main Photo Credit: Greater Scaup - Pair by Len Blumin, 2010. https://www.flickr.com/photos/9062441@N02/4346552530. Licenced with CC BY-NC-ND 2.0, https://creativecommons.org/licenses/by-nc-nd/2.0.
Second Photo Credit: Male Greater Scaup (Aythya marila) taken at Lake Merritt in Oakland, California by Calibas, 2007. https://commons.wikimedia.org/wiki/File:Greater-scaup-male2.jpg. Licenced with CC BY-SA 4.0, https://creativecommons.org/licenses/by-sa/4.0
Third Photo Credit: Greater Scaup Female by Len Blumin, 2007. https://wordpress.org/openverse/image/5cb3f07d-06de-4f33-99ac-b6b7bc875916. Licenced with CC BY-NC-ND 2.0, https://creativecommons.org/licenses/by-nc-nd/2.0