These beautiful birds are native to Australia. Adult black swans will have black body feathers and white wing tips, young birds will have black wing tips and gray body feathers. Males called cobs and females call pens look alike with males usually being slightly larger. These birds are compatible with other smaller waterbirds such as ducks, but often do not get along well with geese or other birds closer to their own size. They should not be kept with other species of swans. White swans pairs have been know to kill black swans. Black swans are mature enough to breed at 1 year of age, but some may not breed until they are 2 or even 3 years old. Pairs are monogamous but will accept a new mate should should the old one be absent. The black swan commonly breeds in the winter, breeding season is generally September - March however eggs can be laid at any time of the year. Clutches consist of 4-6 greenish white eggs, the incubation period is about 35 days. Pairs often become aggressive during during breeding season and same sex pairs may be a good choice for people who are not interested in breeding and would like to own these birds for display only. Although black swans are less cold hardy than most of the white swan species they can still be kept in a northern climate so long they have access to open water year round and are given some protection from protection from the winter weather.