The smallest North American duck of about 13.5" length. Breeding males are strikingly white with black and iridescent markings on the head. Females are browning with a distinctive oval white ear-patch. Buffleheads winter on open lakes, and along sheltered marine areas. They are cavity nesters in Canada and interior Alaska. Birds often are found in small flocks, feeling by diving for mollusks, insect larvae and crustaceans.