Jump to content

Coscoroba swan

From Wikipedia, the free encyclopedia
(Redirected from Coscoroba)

Coscoroba swan
At El Calafate, Argentina
CITES Appendix II [2]
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Subfamily: Anserinae
Genus: Coscoroba
Reichenbach, 1853
Species:
C. coscoroba
Binomial name
Coscoroba coscoroba
(Molina, 1782)

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] It is one of South America's largest species of waterfowl.

Taxonomy and systematics

[edit]

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 puts 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]

Description

[edit]

The coscoroba swan is among the largest waterfowl in South America, but smaller than the true swans, making it the smallest "swan" species.[9] It is somewhat goose-like in appearance with a duck-like bill. It is shorter-necked than other swans. Unlike other swans, its feathers go straight to the base of the bill.[10][11] The adults are completely white, except for black tips to the outer six primary feathers. They have bright pink legs and feet.[9][12]

Their posture and longer legs allow the coscoroba swan to walk easily on land, this also lets them take off into flight quickly from land or water, much faster than the true swans.[10][13][11]

The sexes are similar, but the male is larger.[11][13] Males can weigh up to 5.4 kg (12 lb).[14] The wing length of males is 44–49.8 cm (17.3–19.6 in) and in females 41.5–47.7 cm (16.3–18.8 in). Those in southern Brazil have differing measurements, the wings of males being 37.5–39 cm (14.8–15.4 in) and females 35–35.8 cm (13.8–14.1 in).[13]

Standard Measurements (in southern Brazil)[15]
Male Female
Weight 3.05–5.14 kg (6.7–11.3 lb) 2.4–4.5 kg (5.3–9.9 lb)
Total culmen 62.8–78.8 mm (2.47–3.10 in) 59.8–71.8 mm (2.35–2.83 in)
Tarsus 93.3–117.2 mm (3.67–4.61 in) 84.6–104.5 mm (3.33–4.11 in)
Tail length 145–190 mm (5.7–7.5 in) 141–187 mm (5.6–7.4 in)

Distribution and habitat

[edit]

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).[9][5]

Behavior

[edit]

Feeding

[edit]

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 rarely upends. It also grazes on land. It often feeds with black-necked swans (Cygnus melanocoryphus).[9]

Breeding

[edit]

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 (sometimes mainly the male) 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 around 82–94.5 mm (3.23–3.72 in) in length and 52.9–67 mm (2.08–2.64 in) in width. Males guard females during the incubation period of about 35 days. The chicks hatch with grey-ish white down and a black cap. They are cared for by both adults and fledge at 13–14 weeks of age, and reach adult size after about 8 months. Double-brooding has been documented, where the female began incubating a second clutch 40–50 days after hatching the first.[16] They sometimes stay with adults until they are a year old, even up to two years in captivity. In captivity, coscoroba swans can live 20 years.[9]

Vocalization

[edit]

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".[9]

Status

[edit]

The IUCN has assessed the coscoroba swan as being of Least Concern. It has a large range and its estimated population of 6,700 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".[9]

[edit]

References

[edit]
  1. 1 2 BirdLife International (2016). "Coscoroba Swan Coscoroba coscoroba". IUCN Red List of Threatened Species. 2016 e.T22679866A92832574. doi:10.2305/IUCN.UK.2016-3.RLTS.T22679866A92832574.en. Retrieved 28 September 2022.
  2. ↑ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  3. 1 2 3 Gill, F.; Donsker, D.; Rasmussen, P., eds. (August 2022). "Screamers, ducks, geese, swans". IOC World Bird List. v 12.2. Retrieved August 9, 2022.
  4. 1 2 HBW and BirdLife International (2021) Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 6. Available at: http://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v6_Dec21.zip retrieved August 7, 2022
  5. 1 2 Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 24 July 2022. Species Lists of Birds for South American Countries and Territories. https://www.museum.lsu.edu/~Remsen/SACCCountryLists.htm retrieved July 24, 2022
  6. ↑ Rodrigues, B.S. et al. (2014) Chromosomal studies on Coscoroba coscoroba (Aves: Anseriformes) reinforce the Coscoroba–Cereopsis clade. Biological Journal of the Linnean Society, 111: 274–279.
  7. ↑ Remsen, J. V., Jr., J. I. Areta, E. Bonaccorso, S. Claramunt, A. Jaramillo, D. F. Lane, J. F. Pacheco, M. B. Robbins, F. G. Stiles, and K. J. Zimmer. Version 24 July 2022. A classification of the bird species of South America. American Ornithological Society. https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm retrieved July 24, 2022
  8. ↑ Clements, J. F., T. S. Schulenberg, M. J. Iliff, S. M. Billerman, T. A. Fredericks, J. A. Gerbracht, D. Lepage, B. L. Sullivan, and C. L. Wood. 2021. The eBird/Clements checklist of Birds of the World: v2021. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/ Retrieved August 25, 2021
  9. 1 2 3 4 5 6 7 Carboneras, Carles; Kirwan, Guy M. (2024). "Coscoroba Swan (Coscoroba coscoroba), version 1.1". Birds of the World. doi:10.2173/bow.cosswa1.01.1. ISSN 2771-3105.
  10. 1 2 Madge, Steve; Burn, Hilary (1988). Wildfowl: an identification guide to the ducks, geese and swans of the world. Helm Identification Guides. London: Christopher Helm. ISBN 978-0-7470-2201-5.
  11. 1 2 3 Brazil, Mark (2003). The whooper swan. London: T & A D Poyser. ISBN 978-0-7136-6570-3.
  12. ↑ Madge, Steve; Burn, Hilary (1988). Wildfowl: an identification guide to the ducks, geese and swans of the world. Helm Identification Guides. London: Christopher Helm. ISBN 978-0-7470-2201-5.
  13. 1 2 3 Kear, Janet; Hulme, Mark (2005). Ducks, geese and swans. Bird families of the world. Oxford: Oxford university press. ISBN 978-0-19-854645-0.
  14. ↑ CRC Handbook of Avian Body Masses, 2nd Edition by John B. Dunning Jr. (Editor). CRC Press (2008), ISBN 978-1-4200-6444-5.
  15. ↑ Calabuig, Cecilia Perez; Green, Andy J.; Ferrer, Miguel; Muriel, Roberto; Moreira, Heden (December 2011). "Sexual size dimorphism and sex determination by morphometric measurements in the Coscoroba Swan". Studies on Neotropical Fauna and Environment. 46 (3): 177–184. doi:10.1080/01650521.2011.617545. ISSN 0165-0521.
  16. ↑ Brewer, Gwenda L.; Vilina, Yerko (2002). "Parental Care Behavior and Double-Brooding in Coscoroba Swan in Central Chile". Waterbirds: The International Journal of Waterbird Biology. 25: 278–284. ISSN 1524-4695.
Retrieved from "https://latimes.pages.dev/https-en.wikipedia.org/w/index.php?title=Coscoroba_swan&oldid=1370068540"