This photo shows the short wing bar of the Lesser Scaup. On a Greater, the bright white would extend well into the outer portion of the wing (the primaries).

The Lesser Scaup in this series of 6 photos show the characteristic head shape and the narrow black "nail" on the bill. Some older field guides speak of the male Lesser Scaup having a purple-ish head and the Greater Scaup a green head; however more recent guides discount this differentiation and mention that a Lesser can appear greeinsh in the winter. The male in this series was at least as greenish in the flesh as it appears in these photos.

These photos were taken at the small pond on the east side of Rt 3A in front of Cordage Park on a day when only about 20% of its water was open - fortunately right next to the parking lot allowing be to take these photos from the car.