Black Swan

From Wikipedia, the free encyclopedia

Black Swan
Conservation status
Least Concern
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Order: Anseriformes Family: Anatidae Genus: Cygnus Species: C. atratus
Binomial name
Cygnus atratus Latham, 1790
Subspecies
C. a. atratus Black Swan C. a. sumnerensis New Zealand Swan (extinct)
Synonyms
Anas atrata Latham, 1790 Chenopis atratus

The Black Swan, Cygnus atratus is a large non-migratory waterbird which breeds mainly in the southeast and southwest of Australia. The Black Swan was formerly placed into a monotypic genus, Chenopis.

Contents 1 Distribution 2 Physical Characteristics 3 Diet, Mating, and Nesting 4 History 5 Conservation 6 Media 7 Gallery 8 References 9 External links

[edit] Distribution

The Black Swan is commonly found in the wetlands of southern Australia. Unfortunately, human inhabitance has decreased the population of the swan. The current global population of the Black Swan is approximately around 500,000 individuals.

[edit] Physical Characteristics

The Black Swan is 130cm (52in) long and weighs up to 9kg (20lbs). It has all black plumage, except for the red bill, dark grey legs and white tips on the wing feathers. The neck is long and curved in an "S". There is a white bar near the tip of the red bill. Both sexes are similar, with the female slightly smaller and lighter than the male. The cygnets have light grey plumage.

The Southern Hemisphere swan species differ from the all-white Northern Hemisphere swans in that they all have some black plumage, but only the Black Swan is almost completely black. Its closest living relative is probably the Mute Swan which is most similar, except in its plumage.

[edit] Diet, Mating, and Nesting

Adult Black Swans moult and become flightless each year. During this time they gather in flocks on open lakes. Their diet consists mainly of water plants and near-shore vegetation. Unlike many other waterbirds, they spend their entire lives in the area where they were hatched.

Like other swans, the Black Swan is largely monogamous, pairing for life. According to the Web site "LiveScience", same-sex couples make up to 20 percent of all Black Swan pairings each year, and approximately 25 percent of all Black Swan pairs are of the same sex, and may live together for years. Sometimes, a male in a pair will mate with a female. After she lays eggs, the two-male pair will chase her away and raise her eggs themselves. In other cases, same-sex pairs drive the breeding pairs away from their nests and take over the nest and eggs.

The swans nest on large mounds build in the middle of a shallow lake and reuse the nest every year, restoring or rebuilding it as needed. Male and female swans share the care of the nest, and once the cygnets are fledged, it is not uncommon to see the parents and young swans looking for food together.

[edit] History

Black Swans were discovered by the expedition of Willem de Vlamingh to the west coast of Australia in 1697. Their discovery created great interest in Europe, where "all swans are white" had long been used as a standard example of a well-known scientific truth. The birds are also found along the east coast of Australia, Tasmania and were recently reintroduced into New Zealand. Prior to the arrival of the Māori, a sub-species known as the New Zealand Swan lived in New Zealand. This subspecies was hunted to extinction.

The Black Swan is also very popular as an ornamental waterbird in Western Europe, especially Britain, and escapes are commonly reported. As of yet the population in Britain is not considered to be self-sustaining and so the species is not afforded admission to the official British List, but the Wildfowl & Wetlands Trust have recorded a maximum of nine breeding pairs in the UK in 2001 with an estimate of 43 feral birds in 2003/04 (though that is undoubtedly an under-estimate given the level of monitoring undertaken).

[edit] Conservation

The Black Swan is protected under the Australian National Parks and Wildlife Act, 1974. It is the official state emblem of Western Australia, and has made it's way onto the Flag of Western Australia. It is evaluated as Least Concern on the IUCN Red List of Threatened Species.

Black Swans are also sometimes kept in America, and small populations may live there in feral populations.

[edit] Media

[edit] Gallery

Black Swans on the Gippsland Lakes near Paynesville, Victoria, Australia	Black Swans at Gloucestershire, England	Black Swan at Lake Ginninderra, Canberra, Australia	Black Swan with immature offspring beside Lake Burley Griffin, Canberra, Australia
Cygnus atratus and cygnet at Torrens River, Adelaide, Australia	Black Swan on the bank of the Torrens River, Adelaide, Australia	Cygnus atratus in Singapore Botanical Gardens	Taken in Norfolk Broads, Norfolk County, UK

[edit] References

• BirdLife International (2004). Cygnus atratus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 9 May 2006. Database entry includes justification for why this species is of least concern

[edit] External links

• BirdLife Species Factsheet
• IUCN Red List