Sea Ducks are maritime northern residents, which are well adapted for life in an oceanic environment. They are mainly gregarious and sedentary ducks. Their flight is swift and they usually do not flight far above the water. They disperse over marine waters that freeze less readily than fresh water, which enable them to remain in higher latitudes in winter. Their diet consists of shellfish, molluscs, crustaceans and small fish. Sea Ducks nest either on the ground or in cavities, sometimes above the ground. Their reproductive period is short. Sexual Dimorphism is extreme. Males assume a summer eclipse plumage reminiscent of their more somber mates. They are good divers and may use their wings to aid in submerging, but nearly all depend on their large feet for propulsion. Their wings are held tight against the body, folded in the pockets of oily flanks feathers that keep them perfectly dry and ready for instant flight. Sea Ducks dive very deeply and most are capable of remaining submerged even for as long as two minutes. Some of them are: Common Goldeneye (Bucephala Clangula), Bufflehead (Bucephala Albeola), Barrow’s Goldeneye (Bucephala Islandica), Smew (Mergellus Albellus), Hooded Merganser (Lophodytes Cucullatus) and Common Eider (Somateria Mollissima).