Description from AllAboutBirds.org © Cornell Lab of Ornithology with permission
Tight-knit groups of Lesser Scaup congregate on large lakes, reservoirs, and estuaries during migration and winter, sometimes by the thousands. From afar flocks might just look like floating mats of vegetation on the water. A closer look reveals black-and-white males and chocolatey-brown females floating on the surface and diving below to eat aquatic invertebrates and plants. The devilishly similar Greater Scaup often joins the group too, but the Lesser Scaup wears a tiny peaked hat that sits towards the back of the head, unlike the Greater Scaup's rounded head.