White-backed night heron

White-backed night heron
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Class:Aves
Order:Pelecaniformes
Family:Ardeidae
Genus:Gorsachius
Species: G. leuconotus
Binomial name
Gorsachius leuconotus
(Wagler, 1827)
Synonyms

Nycticorax leuconotus
Calherodius leuconotus

The white-backed night heron (Gorsachius leuconotus) is a species of medium-sized heron in the family Ardeidae, found in sub-Saharan Africa.

Taxonomy

The German naturalist Johann Wagler described the white-backed night heron as Ardea leuconotus in 1827.[2][3] Today the IOC World Bird List places it in the genus Gorsachius,[4] while BirdLife International and the Handbook of the Birds of the World place it in Calherodius.[5][6] Its name derives from a patch of white feathers that form a triangle on its back.[7]

Description

The white-backed night heron is 50–55 cm (20–22 in) in length with a black head and a short crest, or prominent feather display on the top of its head.[8] The heron has large red eyes with white-ringed markings around them, and the lores, or the region behind the eye, are a pale yellow hue.[8][9] The throat feathers are white, whereas the neck and breast are rufous, or a reddish-brown hue.[8] There is a notable white triangular patch along the back formed by the white scapulars, or small feathers, on the shoulder of the bird.[8] The belly feathers are a whitish-brown and the legs are yellow.[3][10] An immature heron can be identified by its streaked breast and the white spots on the upper-wing coverts.[7] Chicks are covered with olive-brown down.[3]

Distribution and habitat

The white-backed night heron is located throughout central and southern Africa, with a range estimated at 20,900,000 km2 (8,100,000 sq mi).[1] Its primary habitat is dense forests with neighboring waterways, particularly streams, lakes, mangroves and marshes.[5]

Behavior and ecology

The white-backed night heron can be found living individually or in pairs.[9] Nocturnal by nature, they roost in the dense vegetation of marshes and forests during the daylight hours, often nesting high within the trees.[5] Their nests are well-hidden, usually built in vegetation near water and sometimes in reedbeds, mangroves, rocks and caves.[5] The nest is built resembling a platform of sticks or reeds, 25–30 cm (9.8–11.8 in) wide.[3] They usually breed during the rainy season or early in the dry season.[5] There are two to three greenish-white eggs in a clutch and incubation lasts roughly 24 to 26 days. The chicks leave the nest after six to seven weeks.[3] The white-backed night heron seems to be sedentary, but it has been observed in some circumstances to have migrated to locations with heavy rain.[11] White-backed night heron are known foragers, meaning they search for food primarily along waterways. They have been observed to eat fish, amphibians, mollusks and insects.[3] Though usually quiet, they let out a loud kroak call when alarmed and a taash call when disturbed.[3]

Status

The population of the white-backed night heron is believed to be stable because it does not appear to undergo significant population declines or experience any notable threats.[5] Due to these factors and its large range, the IUCN Red List has assessed the species to be of least concern.[1] The species is currently experiencing a small number of threats, including habitat loss in southern Africa and hunting in Nigeria, where they are used for traditional medicine.[5]

References

  1. 1 2 3 BirdLife International (2016). "Calherodius leuconotus". IUCN Red List of Threatened Species. IUCN. 2016: e.T22697226A93603192. doi:10.2305/IUCN.UK.2016-3.RLTS.T22697226A93603192.en. Retrieved 10 December 2016.
  2. ↑ Wagler, Johann Georg (1827). Systema avium (in Latin). Stuttgartiae: J.G. Cottae. p. 189, Species 33.
  3. 1 2 3 4 5 6 7 "White-backed Night Heron Nycticorax leuconotus (Wagler)". HeronConservation. IUCN-SSC Heron Specialist Group. 2011. Retrieved 25 October 2016.
  4. ↑ Gill, F.; Donsker, D. (eds.). "Storks, ibis & herons". IOC World Bird List Version 6.4. Retrieved 27 October 2016.
  5. 1 2 3 4 5 6 7 "Species factsheet: Calherodius leuconotus". birdlife.org. BirdLife International. 2016. Retrieved 22 October 2016.
  6. ↑ Martínez-Vilalta, A.; Motis, A.; Kirwan, G. M. (2016). "White-backed Night-heron (Calherodius leuconotus)". In del Hoyo, J.; Elliott, A.; Sargatal, J.; Christie, D. A.; de Juana, E. Handbook of the Birds of the World Alive. Barcelona: Lynx Edicions.
  7. 1 2 Hancock, Peter; Weiersbye, Ingrid (2015). Birds of Botswana. Princeton University Press. p. 62. ISBN 9781400874170.
  8. 1 2 3 4 Borrow, Nik; Demey, Ron (2013). Birds of Senegal and The Gambia. Bloomsbury. p. 42. ISBN 9781408171011.
  9. 1 2 Redman, Nigel; Stevenson, Terry; Fanshawe, John (2010). Birds of the Horn of Africa. Bloomsbury. p. 50. ISBN 9781408135761.
  10. ↑ Newman, Kenneth (2002). Newman's Birds of Southern Africa. Struik. p. 90. ISBN 9781868727353.
  11. ↑ A. P. Martin. "Whitebacked Night Heron" (PDF). The Atlas of Southern African Birds. p. 67.
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