Indian spot-billed duck

Indian spot-billed duck
Indian spot-billed duck
(A. poecilorhyncha)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Anas
Species: A. poecilorhyncha
Binomial name
Anas poecilorhyncha
Forster, 1781
Subspecies
  • A. p. poecilorhyncha Forster, 1781
    Indian Spot-billed Duck
  • A. p. haringtoni (Oates, 1907)
    Burmese Spot-billed Duck

The Indian spot-billed duck (Anas poecilorhyncha) is a dabbling duck which breeds throughout the Indian subcontinent. The name is derived from the yellow and red spot on the bill. The eastern spot-billed duck (A. zonorhyncha) was at one time treated as a subspecies.

Taxonomy

The Indian spot-billed duck was described by the naturalist Johann Reinhold Forster in 1781 under its current binomial name Anas poecilorhyncha.[2][3] The name of the genus Anas is the Latin word for a duck. The specific epithet poecilorhyncha combines the classical Greek words poikilos meaning "pied" or "spotted" and rhunkhos meaning a "bill".[4]

A molecular phylogentic study published in 2009 that compared mitochondrial DNA sequences from ducks, geese and swans in the family Anatidae found that the Indian spot-billed duck was a sister species to a clade containing the Mexican duck, the American black duck, the mottled duck and the mallard.[5]

Two subspecies are now recognised:[6]

The eastern spot-billed duck was formerly considered as a third subspecies. Fieldwork carried out at Hong Kong in southern China and published in 2006 found that although both the eastern spot-billed duck and the Indian spot-billed duck (subspecies A. p. haringtoni) bred in the region at the same time, mixed pairs were only very rarely observed.[7] Based on this observation most taxonomists now treat the eastern spot-billed duck as a separate species.[6][8][9]

Description

In Thiruvanathapuram, October 2016

This duck is around the same size as a mallard and has a scaly patterned body with a green speculum bordered by white. At rest the white stripe stands out and the long neck and the bill with yellow tip and orange red spots at the base are distinctive in the nominate subspecies. The red spots at the base of the bills are absent in haringtoni. It measures 55–63 cm (22–25 in) in length and 83–95 cm (33–37 in) across the wings, with a body mass of 790–1,500 g (1.74–3.31 lb).[10][11] These are mainly grey ducks with a paler head and neck and a black bill tipped bright yellow. The wings are whitish with black flight feathers below, and from above show a white-bordered green The male has a red spot on the base of the bill, which is absent or inconspicuous in the smaller but otherwise similar female. The male does not have an eclipse plumage. The legs and feet are bright orange. Juveniles are browner and duller than adults.[12]

Spot-Billed Duck, India

The eastern spot-billed duck is darker and browner; its body plumage is more similar to the Pacific black duck. It lacks the red bill spot, and has a blue speculum.[12][13]

Both males and females undergo a complete postnuptial moult, dropping all their wing feathers simultaneously.[12]

Distribution

This duck is resident throughout Pakistan and India. Some individuals may migrate. A bird ringed at Bharatpur in Rajasthan on 5 December 1969 was recovered near Novosibirsk in August 1970.[12] It is quite gregarious outside the breeding season and forms small flocks. The northernmost populations have expanded their range northwards by more than 500 km since the early 20th century, possibly in reaction to global warming.[14]

It is a bird of freshwater lakes and marshes in fairly open country and feeds by dabbling for plant food mainly in the evening or at night. The breeding season varies with rainfall and water condition but is July to September in northern India and November to December in southern India. It nests on the ground in vegetation near water, and lays 8-14 eggs. Incubation begins after the last egg is laid (allowing the chicks to hatch simultaneously) and the young hatch after about 24 days. The chicks are black with a yellow back and resemble those of mallards but with a wider eyestripe.[12]

Both the male and female have calls similar to the mallard.

References

  1. ↑ BirdLife International (2016). "Anas poecilorhyncha". IUCN Red List of Threatened Species. International Union for Conservation of Nature. Retrieved 25 July 2017.
  2. ↑ Forster, Johann Reinhold (1781). Indische Zoologie oder systematische Beschreibungen seltener und unbekannter Thiere aus Indien (in Latin and German). Halle, Germany: Johann Jacob Gebauer. p. 23.
  3. ↑ Mayr, Ernst; Cottrell, G. William, eds. (1979). Check-list of Birds of the World. Volume 1 (2nd ed.). Cambridge, Massachusetts: Museum of Comparative Zoology. p. 471.
  4. ↑ Jobling, James A. (2010). The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 46, 311. ISBN 978-1-4081-2501-4.
  5. ↑ Gonzalez, J.; Düttmann, H.; Wink, M. (2009). "Phylogenetic relationships based on two mitochondrial genes and hybridization patterns in Anatidae". Journal of Zoology. 279: 310–318. doi:10.1111/j.1469-7998.2009.00622.x.
  6. 1 2 Gill, Frank; Donsker, David, eds. (2017). "Screamers, ducks, geese & swans". World Bird List Version 7.3. International Ornithologists' Union. Retrieved 23 July 2017.
  7. ↑ Leader, P.J. (2006). "Sympatric breeding of two Spot-billed Duck Anas poecilorhyncha taxa in southern China". Bulletin of the British Ornithologists' Club. 126 (4): 248–252.
  8. ↑ del Hoyo, P.F.; Collar, N.; Kirwan, G.M. (2017). del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D.A.; de Juana, E., eds. "Chinese Spot-billed Duck (Anas zonorhyncha)". Handbook of the Birds of the World Alive. Lynx Edicions. Retrieved 25 July 2017. (Subscription required (help)).
  9. ↑ Lepage, Denis. "Eastern Spot-billed Duck, Anas zonorhyncha Swinhoe, 1866". Avibase. Bird Studies Canada. Retrieved 26 July 2017.
  10. ↑ CRC Handbook of Avian Body Masses by John B. Dunning Jr. (Editor). CRC Press (1992), ISBN 978-0-8493-4258-5.
  11. ↑ Ogilvie & Young, Wildfowl of the World. New Holland Publishers (2004), ISBN 978-1-84330-328-2
  12. 1 2 3 4 5 Ali, Salim & S. Dillon Ripley (1978). Handbook of the Birds of India and Pakistan. Volume 1. (2nd ed.). New Delhi: Oxford University Press. pp. 157–160.
  13. ↑ Baker, E. C. S. (1914). "A note on the sub-species of the Spot-bill Duck Anas poecilorhyncha". Journal of the Bombay Natural History Society. 22 (4): 805–807.
  14. ↑ Kulikova, Irina V.; Yury N. Zhuravlev; Kevin G. McCracken (2004). "Asymmetric hybridization and sex-biased gene flow between eastern Spot-billed Ducks (Anas zonorhyncha) and Mallards (A. platyrhynchos) in the Russian far east". The Auk. 121 (3): 930. ISSN 0004-8038. doi:10.1642/0004-8038(2004)121[0930:AHASGF]2.0.CO;2.
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