| Coscoroba swan | |
|---|---|
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Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Anseriformes |
| Family: | Anatidae |
| Genus: | Coscoroba Reichenbach, 1853 |
| Species: | C. coscoroba |
| Binomial name | |
| Coscoroba coscoroba (Molina, 1782) | |
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The coscoroba swan (Coscoroba coscoroba) is a species of waterfowl in the subfamily Anserinae of the family Anatidae. [3] [4] It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, Uruguay, and the Falkland Islands. [5]
The coscoroba swan's placement within the family Anatidae is not fully agreed upon, with a 2014 genetic study positing a phylogenetic relationship between this species and the Cape Barren goose (Cereopsis novaehollandiae). [6] BirdLife International's Handbook of the Birds of the World has adopted this approach and places the coscoroba swan and Cape Barren goose together in the tribe Cereopsini, which it places as basal to Cygnus and all other geese. [4] However, the South American Classification Committee of the American Ornithological Society, the International Ornithological Committee (IOC), and the Clements taxonomy treat the Cape Barren goose as basal to other geese, which themselves precede the coscoroba and other swans in a linear sequence. Even those three systems differ, with the IOC placing the coscoroba before Cygnus and the other two after it in their lists. [7] [3] [8]
The coscoroba swan is the only member of the genus Coscoroba and has no subspecies. [3]
The coscoroba swan is a medium-large sized waterfowl, but smaller than the true swans, at 90 to 115 cm (35 to 45 in) long with a wingspan of about 155 cm (61 in). Males weigh 3.8 to 5.4 kg (8.4 to 12 lb) and females 3.1 to 4.5 kg (6.8 to 9.9 lb). Their appearance is considered to be slightly unusual, being intermediate between that of geese and true swans. They have completely feathered faces—unusual for true swans—and their feet are located directly under their bodies, enabling the coscoroba swan to walk more efficiently than the “waddling” of most waterfowl. [9] Physically, coscoroba swans have been compared to the American Pekin duck, albeit larger and with darker, redder bills and feet (Pekin ducks have bright orange bills and feet). [10] The sexes have the same plumage; upon hatching, the chicks have blue-grey bills and feet and black striping running down the length of their bodies (to aid in camouflage from predators), with this eventually fading by about eight months of age. The adults are completely white, except for black tips to the outer six primary feathers, though this black is often barely visible on the closed wing unless the bird is in flight. [11] [12]
The coscoroba swan is a year-round resident of central Argentina and along the Uruguay-southern Brazil coast. It also breeds but does not winter from southern Chile and Argentina south to Tierra del Fuego and occasionally to the Falkland Islands. In winter its range extends north to central Chile, northern Argentina, Paraguay, Uruguay, and southern Brazil. It has been recorded as a vagrant in Bolivia and at several locations in Brazil north of its usual limit. The coscoroba swan inhabits well-vegetated lagoons, freshwater swamps, and sometimes human-made reservoirs. It is mainly a bird of the lowlands, though there are scattered records as high as 1,300 m (4,300 ft) and at least one at 2,000 m (6,600 ft). [11] [5]
The coscoroba swan's diet has not been studied in detail, but it apparently feeds on aquatic and some terrestrial plants, small aquatic invertebrates, and small fish. It forages mainly while swimming or wading in shallow water and in contrast to other swans seldom upends. It also grazes on land. It often feeds with black-necked swans (Cygnus melanocoryphus). [11]
The coscoroba swan breeds in the local spring, which is May to October in northern Argentina, July to December in Chile, and July and August in southern Brazil. The species forms long-term pair bonds. Its nest is a mound of vegetation lined with soft grass constructed by both members of a pair on a small islet, partially floating in a reedbed or long grass close to water. The clutch size is four to nine oval eggs that weigh about 167 g (5.9 oz) with dimensions of about 88 by 60 mm (3.5 by 2.4 in). Males guard females during the incubation period of about 35 days. Both parents care for the young through fledging at 14 weeks and beyond, sometimes until they are a year old. In captivity, coscoroba swans can live 20 years. [11]
The coscoroba swan makes an onomatopoeic "cos-cor-oo", usually as a threat to intruders. They also make a "monosyllabic hooting note" as a contact call between mates. Immature birds make "loud chirps and trills". [11]
The IUCN has assessed the coscoroba swan as being of Least Concern. It has a large range and its estimated population of 6700 to 17,000 mature individuals is believed to be stable. No immediate threats have been identified. [1] The species' population varies dramatically at different parts of its range, being fairly common in Argentina, uncommon in Paraguay and Uruguay, rare in Chile, and uncertain in Brazil. The "[g]reatest threat seems to be loss of temperate marsh habitats due to urbanization and agricultural developments". [11]
A goose is a bird of any of several waterfowl species in the family Anatidae. This group comprises the genera Anser and Branta. Some other birds, mostly related to the shelducks, have "goose" as part of their names. More distantly related members of the family Anatidae are swans, most of which are larger than true geese, and ducks, which are smaller.
The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating on the water surface, and in some cases diving in at least shallow water. The family contains around 174 species in 43 genera.
Anseriformes is an order of birds also known as waterfowl that comprises about 180 living species of birds in three families: Anhimidae, Anseranatidae, and Anatidae, the largest family, which includes over 170 species of waterfowl, among them the ducks, geese, and swans. Most modern species in the order are highly adapted for an aquatic existence at the water surface. With the exception of screamers, males have penises, a trait that has been lost in the Neoaves. Due to their aquatic nature, most species are web-footed.
The Anserinae are a subfamily in the waterfowl family Anatidae. It includes the swans and the true geese. Under alternative systematical concepts, it is split into two subfamilies, the Anserinae contain the geese and the ducks, while the Cygninae contain the swans.
The Oxyurini are a tribe of the duck subfamily of birds, the Anatinae. It has been subject of considerable debate about its validity and circumscription. Some taxonomic authorities place the group in its own subfamily, the Oxyurinae. Most of its members have long, stiff tail feathers which are erected when the bird is at rest, and relatively large, swollen bills. Though their relationships are still enigmatic, they appear to be closer to swans and true geese than to the typical ducks. The highest diversity is found in the warmer parts of the Americas, but at least one species occurs in a major part of the world.
The black-necked swan is a species of waterfowl in the tribe Cygnini of the subfamily Anserinae. It is found in Argentina, Brazil, Chile, Uruguay, and the Falkland Islands.
The shelducks, most species of which are found in the genus Tadorna, are a group of large birds in the Tadorninae subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans.
The Andean goose is a species of waterfowl in tribe Tadornini of subfamily Anserinae. It is found in Argentina, Bolivia, Chile, and Peru.
The black-headed duck is a South American duck in subfamily Oxyurinae of family Anatidae. It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay.
The ashy-headed goose is a species of waterfowl in tribe Tadornini of subfamily Anserinae. It is found in Argentina and Chile.
The ruddy-headed goose is a species of waterfowl in tribe Tadornini of subfamily Anserinae. It is found in Argentina, Chile, and the Falkland Islands.
The Orinoco goose is a Near Threatened species of waterfowl in the tribe Tadornini of subfamily Anserinae. It is found in every mainland South American country except Chile, French Guiana, Suriname, and Uruguay.
The upland goose or Magellan goose is a sheldgoose of the shelduck-sheldgoose subfamily of the Anatidae, the biological family that includes the ducks and most duck-like waterfowl such as the geese and swans. Sheldgeese resemble true geese and display similar habits, yet they are more closely related to shelducks and ducks. The two recognized subspecies of upland goose are the continental picta subspecies and the insular (island) leucoptera subspecies.
The southern screamer is a species of bird in family Anhimidae of the waterfowl order Anseriformes. It is found in Argentina, Bolivia, Brazil, Paraguay, Peru, and Uruguay.
Anser is a waterfowl genus that includes the grey geese and the white geese. It belongs to the true goose and swan subfamily of Anserinae under the family of Anatidae. The genus has a Holarctic distribution, with at least one species breeding in any open, wet habitats in the subarctic and cool temperate regions of the Northern Hemisphere in summer. Some also breed farther south, reaching into warm temperate regions. They mostly migrate south in winter, typically to regions in the temperate zone between the January 0 °C (32 °F) and 5 °C (41 °F) isotherms.
The glittering-bellied emerald is a species of hummingbird in the "emeralds", tribe Trochilini of subfamily Trochilinae. It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay.
The rufous-chested dotterel or rufous-chested plover, is a species of bird in subfamily Charadriinae of family Charadriidae. It is found in Argentina, Brazil, Chile, Uruguay, and the Falkland Islands.
The spot-winged pigeon is a species of bird in the family Columbidae. It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, Peru, and Uruguay.
The rufous-sided crake is a species of bird in subfamily Rallinae of family Rallidae, the rails, gallinules, and coots. It is found in every mainland South American country except Chile.
The white-banded mockingbird is a species of bird in the family Mimidae. It is found in Argentina, Bolivia, Brazil, Chile, Paraguay, and Uruguay.
In this Keeper Talk, aviculturist Jessica introduces one of the more unusual waterfowl species. Is it really a swan? Is it a goose? Or is it more like a duck? Watch the video to find out!
Media related to Coscoroba coscoroba at Wikimedia Commons
