Greater Scaup: (Aythya marila)

Also known as Bluebills. For most birders the Greater Scaup is a winter duck or a rarity. It is found in flocks, or rafts, often mixed with other diving ducks. It feeds on oysters, small clams, and rock crabs in sheltered bays, inshore waters, and the mouths of large rivers, but in summer it also consumes quantities of buds and seeds of submerged plants.