n.
Long-necked, heavy-bodied, big-footed waterfowl (genus Cygnus , family Anatidae).
Among waterfowl, swans are the largest and fastest, both swimming and flying; at about 50 lbs (23 kg), the mute swan ( C. olor ) is the heaviest flying bird. Swans dabble in shallows for aquatic plants. Five all-white, black-legged species live in the Northern Hemisphere; a black and a black-necked species live in the Southern Hemisphere. Males (cobs) and females (pens) look alike. Swans mate for life. The cob keeps guard while the pen incubates, on average, six eggs on a heap of vegetation; the young (cygnets) are tended for several months. Their graceful form when swimming has made swans emblems of beauty for centuries.
Mute swan ( Cygnus olor ) and cygnet
Arthur W. Ambler
The National Audubon Society Collection/Photo Researchers