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.

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.

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.

They look remarkably similar to the Lesser Scaup, with only slight differences in head shape: the Greater Scaup has a rounded head, the Lesser Scaup a peaked head. These underwater divers eat aquatic invertebrates and plants at the bottom of lakes and bays.

First-winter female Lesser Scaup (Caerlaverock WWT, Dumfries and Galloway, 18 February 2007). Again, this young Lesser Scaup shows features suggestive of both Tufted Duck and Greater Scaup. Its small body and neat proportions suggest the former while its grey mantle clearly indicates the latter.