The
black swan (
Cygnus atratus) is a large
waterbird, a species of
swan which breeds mainly in the southeast and southwest regions of
Australia. Within Australia they are nomadic, with erratic migration patterns dependent upon climatic conditions. Black swans are large birds with mostly black
plumageand red
bills. They are monogamous breeders, and are unusual in that one-quarter of all pairings are
homosexual, mostly between males. Both partners share incubation and cygnet rearing duties.
Birdlife Australia Wikipedia