(Courtesy of USGS Patuxent
Wildlife Research Center)
These are large diving ducks, reaching lengths of 20" (50 cm). The males have distinctive coloring: a glossy green head and a prominent round white spot before the eye. Females are dusky gray and brown in color. They are excellent swimmers using their large, powerful feet to reach the bottom of the Bay for food. They feed on small mussels and other mollusks in addition to eelgrass. They most often appear on the Bay in winter.