There are six species of swan in the genus Cygnus; in addition there is another species known as the coscoroba swan, although this species is no longer considered one of the true swans. Swans are the largest waterfowl species of the subfamily Anserinae, family Anatidae (order Anseriformes). Swans are gracefully long-necked, heavy-bodied, big-footed birds that glide majestically when swimming and fly with slow wingbeats and with necks outstretched. They migrate in diagonal formation or V-formation at great heights, and no other waterfowl moves as fast on the water or in the air.
See also: Bewick's swan, Black swan, Black necked swan, Coscoroba swan, Mute swan, Trumpeter Swan, Whooper Swan