Nicolet Bird Sanctuary During the spring migration, there were nearly 500,000 snow goose ("Chen caerulescens"), or nearly all of the population of species "atlantica". It is also an important site for the migration of Canada (Branta canadensis), where more than 100,000 individuals were observed in 1998. There are also a number ("Black duck") ("Anas rubripes") and of black scoter ("Melanitta nigra"). During the autumn, there are a significant number of pintail ("Anas acuta"), small scaup ("Aythya affinis"), Scaup and golden-eye withered ("Bucephala clangula"). Ducks nesting on the site are the Aix sponsa, the nasal duck, Anas clypeata, the gill duck, Anas strepera), 'American
Lesser scaup more often than those of the greater scaup—particularly during flight—but their call is weaker, a guttural "brrtt, brrtt". Lesser scaup are often hard to distinguish from the greater scaup when direct comparison is not possible, but in North America a large scaup flock will often have both species present. Females, juveniles and drakes in eclipse plumage are hard to identify; there is considerable overlap in length between the two species, but greater scaup are usually noticeably more bulky. Lesser scaup females and immatures tend to have less white around the bill, but this too varies considerably between individual birds. The