The bufflehead is the smallest diving duck in North America. Males weigh about 450 g (1 lb.) and females 325 g (11 oz.). Breeding males are striking with a black head glossed green and purple, a large white patch covering the back of the head, a black back, white underparts, and black wings with a large white patch covering most of the inner wing.
Sea Duck Information Series fact sheet
Species Knowledge Summary and Information Needs (document coming soon)