Large scoter, with distinctive white patch on wing. Males are black and have small white mark under eye, dark knob on the bill, and pink bill tip. Females are dark chocolate-brown and have two rounded white patches on face. Winters on coastal waters and large freshwater lakes. Occasionally found on large inland lakes during migration. Dives frequently, feeding on mollusks and crustaceans. Velvet Scoter similar. Both sexes separated from Velvet Scoter by knobbier bill shape; males by more white around the eye and reddish bill coloration.