A small (15-16 inches), oddly-shaped duck, the male Ruddy Duck in summer is most easily identified by its chestnut-brown body, black cap, white cheeks, and blue bill. In winter, the male loses much of its color, becoming gray-brown above and mottled gray below with a gray bill while retaining its solid white cheeks. Females are similar to winter males, but have gray-brown cheeks. This species is one of several “stiff-tailed” ducks, all of which have short, stiff tails which are often held erect. The Ruddy Duck breeds widely in the western United States, southwestern Canada, and western Mexico. Smaller numbers breed further east in the Great Lakes region and along the St. Lawrence River. In winter, this species vacates northern portions of its range, and may be found at lower elevations across the U.S.and most of Mexico. Other non-migratory populations occur in Central America and in the West Indies, and an introduced population breeds in Britain. Ruddy Ducks breed in a variety of freshwater wetlands, primarily those surrounded by grassland or prairie. In the winter, this species may be found in freshwater wetlands as well as in brackish bays and estuaries. Ruddy Ducks primarily eat small invertebrates, including insects and crustaceans. One of many species of ducks which dive while foraging for food, Ruddy Ducks may be observed submerging themselves to feed on invertebrates in the water or on the bottom. Although Ruddy Ducks are quite agile while in the water, this species is among the least terrestrial ducks in its range, being almost entirely incapable of walking on land. Ruddy Ducks are primarily active during the day.