The ring-necked duck (*Aythya collaris*) is a medium-sized diving duck found across North America, named for a subtle chestnut collar at the base of its neck that is rarely visible in the field. The male is striking in appearance, with a glossy black head that shows a purple iridescence in good light, a black back and breast, pale gray flanks divided from the breast by a crisp white vertical stripe, and a bold white ring near the tip of its slate-blue bill — a feature far more useful for identification than its namesake neck ring. The female is more subdued, with a brown body, a white eye ring, and a similar patterned bill. Both sexes have a distinctly peaked, angular head shape that sets them apart from similar species like the scaup. Ring-necked ducks prefer freshwater habitats such as wooded ponds, marshes, and lakes with aquatic vegetation, and they dive to feed on plant matter, seeds, and invertebrates. They are highly migratory, breeding across the boreal forests of Canada and the northern United States and wintering throughout the southern U.S., Mexico, and the Caribbean.