This medium-sized duck is smaller than a Mallard and can be identified by its huge, spoon-shaped bill, which is visible from a distance and in flight. During the breeding season, males have a dark green head, a white breast, and chestnut-colored sides and belly. Females are buffy-brown overall with a large, distinctive bill and a chalky-blue upperwing. They forage by sifting through the water, often swimming in spirals while moving in groups.