Lesser scaup duller and have hardly any white at the bill base. Both sexes have white secondary remiges, a blue-grey bill with a black "nail" at the tip and grey feet; the drakes have a bright yellow iris, while that of females is orange or amber and that of immatures is brown. Downy hatchlings look much like those of related species, with dark brown upperparts and pale buff underparts, chin, supercilium and back spots. These birds are not very vocal, at least compared to dabbling ducks. Hens give the namesake discordant "scaup, scaup" call; in courtship drakes produce weak whistles. Hens vocalize
Greater scaup 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