Plumage is black and white on the male, brown and white on the female. Goldeneyes dive for crustaceans, insects, mollusks and fish. Common spring-fall migrants, they breed across Canada and in Alaska, and winter in Pennsylvania and across the continental United States. Small and stubby, the ruddy duck has a short, thick neck , an upturned tail, and white cheek patches under a dark cap. In flight, ruddy ducks skim low over the water in compact flocks.
Juveniles eat a larger proportion of energy-rich animal food than do adults.
They breed mainly in southwestern Canada, and winter along the United States coasts and in Mexico. The species have distinctive, colorful plumage. They fly fast and low over the water. All three merganser species breed in Pennsylvania, although their principal range is farther north. Breeding habitat is heavy timber around lakes, ponds, rivers and streams.