Greater Scaup
Aythya marila
The adult greater scaup is 39–56 cm (15–22 in) long with a 71–84 cm (28–33 in) wingspan and a weight of 726–1,360 g (1.601–2.998 lb). It has a light blue bill with a small black nail on the tip, yellow eyes, and is 20% heavier and 10% longer than the closely related lesser scaup. 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.
ID text from Wikipedia, CC BY-SA 4.0
Long-tailed Duck
Clangula hyemalis
Adults have white underparts, though the rest of the plumage goes through a complex moulting process. The male has a long pointed tail (10 to 15 cm (3.9 to 5.9 in) long) and a dark grey bill crossed by a pink band. In winter, the male has a dark cheek patch on a mainly white head and neck, a dark breast and mostly white body. In summer, the male is dark on the head, neck and back with a white cheek patch. The female has a brown back and a relatively short pointed tail. In winter, the female's head and neck are white with a dark crown. In summer, the head is dark.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
And 26 more countries.
Learn this pair in BeakBrain
Photo and call practice, free in any browser.
Play BeakBrainPhotos and recordings are credited to their authors under the licence shown. Full profiles: Greater Scaup and Long-tailed Duck.