White-backed night heron
|White-backed night heron|
The German naturalist Johann Wagler described the white-backed night heron as Ardea leuconotus in 1827. Today the IOC World Bird List places it in the genus Gorsachius, while BirdLife International and the Handbook of the Birds of the World place it in Calherodius. Its name derives from a patch of white feathers that form a triangle on its back.
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. 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. The throat feathers are white, whereas the neck and breast are rufous, or a reddish-brown hue. There is a notable white triangular patch along the back formed by the white scapulars, or small feathers, on the shoulder of the bird. The belly feathers are a whitish-brown and the legs are yellow. An immature heron can be identified by its streaked breast and the white spots on the upper-wing coverts. Chicks are covered with olive-brown down.
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). Its primary habitat is dense forests with neighboring waterways, particularly streams, lakes, mangroves and marshes.
Behavior and ecology
The white-backed night heron can be found living individually or in pairs. Nocturnal by nature, they roost in the dense vegetation of marshes and forests during the daylight hours, often nesting high within the trees. Their nests are well-hidden, usually built in vegetation near water and sometimes in reedbeds, mangroves, rocks and caves. The nest is built resembling a platform of sticks or reeds, 25–30 cm (9.8–11.8 in) wide. They usually breed during the rainy season or early in the dry season. 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. 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. White-backed night herons are known foragers, meaning they search for food primarily along waterways. They have been observed to eat fish, amphibians, mollusks and insects. Though usually quiet, they let out a loud kroak call when alarmed and a taash call when disturbed.
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. Due to these factors and its large range, the IUCN Red List has assessed the species to be of least concern. 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.
- 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.
- Wagler, Johann Georg (1827). Systema avium (in Latin). Stuttgartiae: J.G. Cottae. p. 189, Species 33.
- "White-backed Night Heron Nycticorax leuconotus (Wagler)". HeronConservation. IUCN-SSC Heron Specialist Group. 2011. Retrieved 25 October 2016.
- Gill, F.; Donsker, D. (eds.). "Storks, ibis & herons". IOC World Bird List Version 6.4. Retrieved 27 October 2016.
- "Species factsheet: Calherodius leuconotus". birdlife.org. BirdLife International. 2016. Retrieved 22 October 2016.
- 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. (eds.). Handbook of the Birds of the World Alive. Barcelona: Lynx Edicions.
- Hancock, Peter; Weiersbye, Ingrid (2015). Birds of Botswana. Princeton University Press. p. 62. ISBN 9781400874170.
- Borrow, Nik; Demey, Ron (2013). Birds of Senegal and The Gambia. Bloomsbury. p. 42. ISBN 9781408171011.
- Redman, Nigel; Stevenson, Terry; Fanshawe, John (2010). Birds of the Horn of Africa. Bloomsbury. p. 50. ISBN 9781408135761.
- Newman, Kenneth (2002). Newman's Birds of Southern Africa. Struik. p. 90. ISBN 9781868727353.
- A. P. Martin. "Whitebacked Night Heron" (PDF). The Atlas of Southern African Birds. p. 67.