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, the black swan is nomadic, with erratic migration patterns dependent on climatic conditions. It is a large bird with black plumage and a red bill. It is a monogamous breeder, with both partners sharing incubation and cygnet-rearing duties.
The black swan was introduced to various countries as an ornamental bird in the 1800s, but has managed to escape and form stable populations.
The black swan is common in the wetlands of southwestern and eastern Australia and adjacent coastal islands. In the south west its range encompasses an area between North West Cape, Cape Leeuwin and Eucla; while in the east it covers a large region bounded by the Atherton Tableland, the Eyre Peninsula and Tasmania, with the Murray Darling Basin supporting very large populations of black swans. It is uncommon in central and northern Australia.
The black swan's preferred habitat extends across fresh, brackish and salt water lakes, swamps and rivers with underwater and emergent vegetation for food and nesting materials. It also favors permanent wetlands, including ornamental lakes, but can also be found in flooded pastures and tidal mudflats, and occasionally on the open sea near islands or the shore.
Like other swans, the black swan is largely monogamous, pairing for life (about 6% divorce rate). Recent studies have shown that around a third of all broods exhibit extra-pair paternity. An estimated one-quarter of all pairings are homosexual, mostly between males. They steal nests, or form temporary threesomes with females to obtain eggs, driving away the female after she lays the eggs.
Physical characteristics
Color: Almost entirely black with white tips on the wings, which are only visible in flight or when lifted.
Bill: Deep orange-red with a narrow white band near the tip.
Eyes: Red.
Size: Lengths are typically 110–140 cm (43–55 in), and they can weigh up to 9 kg (20 lbs).
Neck: Have the longest neck-to-body ratio of any swan species, with 24 or 25 neck vertebrae compared to a human's seven.
Black swans are the only entirely black swan species, with dark body plumage, white wing tips, and a red bill with a white band. They are native to Australia but have been introduced elsewhere and prefer habitats like lakes and rivers where they feed on aquatic plants. They form monogamous, lifelong bonds and both parents incubate eggs and raise their young (cygnets).
Habitat and diet
Native range: Australia and Tasmania.
Introduced range: New Zealand, Europe, and other parts of the world.
Habitat: Prefer large, permanent wetlands such as lakes, rivers, ponds, and estuaries, needing at least 40 meters of clear water to take off.
Diet: Primarily herbivorous, feeding on algae, aquatic plants, and grains from cultivated fields.
Reproduction and life cycle
Mating: Form monogamous, lifelong bonds with their mates.
Nesting: Build nests near or on the water.
Eggs: Lay 4 to 8 eggs.
Incubation: Both parents take turns incubating the eggs for 29 to 36 days.
Young: Cygnets can swim shortly after hatching and stay with their parents for several months until they are ready to fledge.
Maturity: Reach reproductive maturity in about 2 to 3 years.
