Although male ring-necked ducks superficially resemble lesser scaup, their peaked, angular head profile, distinctive white bill markings and uniformly dark upper wings distinguish them. The "ringneck" name is derived from a faint brownish ring around the base of the neck, which is visible only upon close inspection. They prefer sedge-meadow marshes, swamps and bogs surrounded by woody vegetation. In winter, ring-necked ducks use a variety of habitats, such as fresh and brackish marshes, shallow lakes, estuarine bays and coastal lagoons. Ring-necked ducks dive in shallow water to feed on the tubers, seeds and leaves of moist-soil and aquatic plants (pondweeds, coontail, water milfoil, hydrilla, sedges, grasses, wild rice, etc.). They also eat aquatic insects, snails and clams.