Distinctly larger than Lesser Scaup, this common diving duck is often seen in large flocks on expansive bodies of water like rivers, bays, lakes, and reservoirs. Head shape is the best way to differentiate between these two near identical species. Greater Scaup has a rounded head, with the highest point at the front of the crown, while the highest point on the head of a Lesser Scaup is at the back of the crown. Male: Black at both ends, with white in between. The head shows green iridescence in good light. The back has fine gray barring. The sides appear bright white at a distance, and generally look bright than the slightly dingier sides of Lesser Scaup. The blue bill is quite large and has a large black nail at the tip. The eye is bright yellow. In Summer and early Fall adult males assume a cryptic female-like appearance, but lack the white around the base of the bill. Female: Dark brown overall with a large white patch at the base of the bill. Some females show a pale patch on the cheeks. Bill is dull gray. In flight, both sexes show a white stripe along the trailing edge of the wing, extending into the primaries.

Ring-necked Ducks have a more peaked hindcrown than either of the scaup and there is always noticeable contrast between the dark back panel and paler flanks (light gray in males, medium brown in females). They also lack the white wing stripe shown by Greater Scaup. Male Tufted Ducks show even brighter white flanks that contrast with a black back panel, plus the elongated tuft feathers are almost always visible. Female Tufted Ducks are near identical to female scaup, but the white at the base of the bill is much more restricted and sometimes absent and, if seen well, an abbreviated tuft is usually visible.

Length: 44 (cm) Wingspan: 81 (cm)

Voice:

Usually silent. Alarm call is a repeated Cawp.

Habitat:

Nests near shallow wetlands. In migration and winter, uses large bodies of water (lakes and reservoirs), broad river channels and marine waters. Far less likely on small ponds.

Behavior:

Usually do not mix with other species. When other species are present in a flock, Great Scaups usually form small groups within the larger flock. When feeding, some individuals remain at the surface to watch for predators.

Feeding:

Dives for both plant and animal foods. Larger food items, such as larger shellfish, are brought to the surface before swallowing.