Lesser vs Greater Scaup: Female. The peak of the crown on the Greater Scaup is toward the front of the head and over the eye. The peak of the head on the Lesser falls on the back of the head. Greater Scaup sometimes have the appearance of a flat spot on the head. Some female Greater Scaup may have a pale cheek patch in spring and summer.

Once Ring-necked and Tufted Ducks are out of the running, you’re left with the pair that’s toughest to tell apart: scaup. During winter, location can be a deciding factor. Greater Scaup tend to choose saltwater bodies, while Lesser Scaup are found in freshwater zones further inland.

The greater scaup is a slightly larger, chunkier duck overall, though the size difference is subtle. The female greater is noticeably larger-bodied than the petite female lesser scaup. Other Hints. Lesser scaup tend to flock in dense rafts in winter more often than greaters. Listen for the subtly raspy voices of courting males in spring.

Female. Lesser Scaup usually shows a peak toward the rear of the crown and a flatter back of the neck than Greater Scaup, which has a more smoothly rounded head. © Alix d'Entremont / Macaulay Library Nova Scotia, March 18, 2014

The main differences are that Greater Scaup have a rounder head, a longer wing stripe, and prefer saltwater habitats, while Lesser Scaup have a peaked head, shorter wing stripe, and favor freshwater areas. Pay close attention to these details to tell them apart.