Lesser Scaup

The Lesser Scaup is the most numerous diving duck in North America and the smaller, more widespread of the two scaup species. The breeding drake shares the Greater Scaup's overall black-white-and-gray pattern, but its head shows a subtle purplish gloss (versus greenish) and is more peaked, with the highest point of the crown toward the rear rather than evenly rounded.

Females closely resemble female Greater Scaup, brown overall with a bold white patch at the base of the bill, and the two species require careful attention to head shape and, in flight, wing-stripe pattern to reliably distinguish.

Key Field Marks

• Peaked crown, highest toward the rear of the head, giving a slight bump profile
• Breeding drake: subtle purplish head gloss, black breast, pale gray back, white flanks
• Female: brown overall with a bold white patch at the base of the bill
• In flight, white wing stripe is shorter, mostly confined to the secondary feathers (versus extending into the primaries on Greater Scaup)

Similar Species

The Greater Scaup is very similar but slightly larger, with a rounder head (broadest toward the back), a greenish head gloss, and a longer white wing stripe extending into the primaries. Ring-necked Ducks have a more angular, sharply peaked head and a ringed bill, and females lack the scaup's bold white face patch.

Lesser Scaup breed across the northern prairies, parklands, and boreal regions of North America, favoring marshes, ponds, and lakes with good emergent vegetation, extending somewhat farther south and inland than the more Arctic-breeding Greater Scaup. They winter very widely across the United States, Mexico, and Central America on lakes, reservoirs, rivers, and coastal bays.

As the most abundant diving duck on the continent, Lesser Scaup form large wintering flocks, sometimes numbering in the thousands, on productive lakes and coastal waters, though populations have declined somewhat from historic highs.

Lesser Scaup are diving ducks, feeding on mollusks, aquatic invertebrates, seeds, and plant material obtained by diving in a wide range of freshwater and coastal habitats. They are highly social, often forming large, dense rafts on open water, especially during migration and winter.

The voice is generally quiet outside the breeding season; males give soft, wheezy courtship notes, while females give a harsher scolding call. Nests are built on the ground in dense grass or marsh vegetation near water, with females incubating a clutch of 8-12 eggs alone.