Cattle egret
The cattle egret (Bubulcus ibis) is a cosmopolitan species of heron (family Ardeidae) found in the tropics, subtropics and warm temperate zones.
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| Genus: | Bubulcus
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| Bubulcus ibis (Linnaeus, 1758)
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It is the only member of the genus Bubulcus, with two subspecies, the western cattle egret and the eastern cattle egret. It is a stocky white bird adorned with buff plumes in the breeding season. It nests in colonies, usually near bodies of water and often with other wading birds.
Unlike most other herons, it feeds in relatively dry grassy habitats, often with cattle or other large mammals. It catches insect and small vertebrate prey disturbed by these animals. It also captures ticks and flies from cattle.
Originally native to parts of Asia, Africa and Europe, it has undergone a rapid expansion in its distribution and successfully colonised much of the rest of the world. This is because humans now raise domesticated cattle throughout most of the world. Some populations of the Cattle Egret are migratory and others disperse after breeding.
It can be a safety hazard at airfields, and has been implicated in the spread of tick-borne animal diseases.
Distribution and habitat
The cattle egret has undergone one of the most rapid and wide reaching natural expansions of any bird species.[2]
It was originally native to parts of Southern Spain and Portugal, tropical and subtropical Africa and humid tropical and subtropical Asia. In the end of the 19th century it began expanding its range into southern Africa, first breeding in the Cape Province in 1908.[3]
Cattle egrets were first sighted in the Americas on the boundary of Guiana and Suriname in 1877, having apparently flown across the Atlantic Ocean.[4][5] It was not until the 1930s that the species is thought to have become established in that area.[6]
The species first arrived in North America in 1941 (these early sightings were originally dismissed as escapees), bred in Florida in 1953, and spread rapidly, breeding for the first time in Canada in 1962.[3] It is now commonly seen as far west as California. It was first recorded breeding in Cuba in 1957, in Costa Rica in 1958, and in Mexico in 1963, although it was probably established before that.[6]
In Europe the species had historically declined in Spain and Portugal, but in the latter part of the 20th century it expanded back through the Iberian Peninsula, and then began to colonise other parts of Europe; southern France in 1958, northern France in 1981 and Italy in 1985.[3] Breeding in the United Kingdom was recorded for the first time in 2008 only a year after an influx seen in the previous year.[7][8] In 2008 cattle egrets were also reported as having moved into Ireland for the first time.[9]
In Australia the colonisation began in the 1940s, with the species establishing itself in the north and East of the continent.[10] It began to regularly visit New Zealand in the 1960s.
Since 1948 the cattle egret has been permanently resident in Israel. Prior to 1948 it was only a winter visitor. [11]
The massive and rapid expansion of the cattle egret's range is due to its relationship with humans and their domesticated animals. Originally adapted to a commensal relationship with large browsing animals, it was easily able to switch to domesticated cattle and horses. As livestock keeping spread throughout the world it was able to occupy otherwise empty niches.[12]
Feeding
The bird feeds on a wide range of prey, particularly insects, especially grasshoppers, crickets, flies (adults and maggots),[13] and moths, as well as spiders, frogs, and earthworms.[14][15]
The species is usually found with cattle and other large grazing and browsing animals, and catches small creatures disturbed by the mammals. Studies have shown that Cattle Egret foraging success is much higher when foraging near a large animal than when feeding singly.[16] When foraging with cattle, it has been shown to be 3.6 times more successful in capturing prey than when foraging alone. Its performance is similar when it follows farm machinery, but it is forced to move more.[17]
Cattle Egret Media
Adult eastern cattle egret (Ardea coromanda) showing the red flush on the legs and bill, present at the height of the breeding season
Range expansion in the Americas
A flock of western cattle egrets in a tree at Jacutinga, Minas Gerais, Brazil
Multiple contact calls at a nighttime roost.
Adult western cattle egret feeding a nestling in Apenheul zoo
A nonbreeding adult western cattle egret eating a frog in the Gambia.
Western cattle egrets waiting for scraps at the fish market of Victoria, Seychelles.
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References
- ↑ BirdLife International (2008). Bubulcus ibis. 2008 IUCN Red List of Threatened Species. IUCN 2008. Retrieved on 2008-11-05. Database entry includes justification for why this species is of least concern
- ↑ Telfair II, Raymond C. (2006). "Cattle egret (Bubulcus ibis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from The Birds of North America Online doi:10.2173/bna.113
- ↑ 3.0 3.1 3.2 Martínez-Vilalta, A. & A. Motis (1992) "Family Ardeidae (Herons)" in del Hoyo, J.; Elliot, A. & Sargatal, J. (editors). (1992). Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions. ISBN 8487334091, 401–402
- ↑ Krebs, Elizabeth A.; Riven-Ramsey, Deborah; Hunte W. 1994. The Colonization of Barbados by Cattle Egrets (Bubulcus ibis) 1956–1990. Colonial Waterbirds. Waterbird Society 17 (1): 86–90. doi:10.2307/1521386. http://jstor.org/stable/1521386.
- ↑ "Cattle Egret". All about birds. Cornell Laboratory of Ornithology. Retrieved 2008-02-28.
- ↑ 6.0 6.1 Crosby, G. (1972). "Spread of the Cattle Egret in the Western Hemisphere" (PDF). Journal of Field Ornithology. 43 (3): 205–212. Archived from the original (PDF) on 2012-03-30. Retrieved 2011-02-06.
- ↑ "First cattle egrets breed in UK". BBC News. 2008-07-23. http://news.bbc.co.uk/1/hi/england/somerset/7521476.stm. Retrieved 2008-07-24.
- ↑ Nightingale, Barry; Eric Dempsey (2008). "Recent reports" (PDF). British Birds. 101 (2): 108. Archived from the original (PDF) on 2009-11-10. Retrieved 2011-02-06.
- ↑ "Flying in to make new friends". Irish Independent, 15-Jan-2008.
- ↑ Maddock, M. (1990). "Cattle Egrets: South to Tasmania and New Zealand for the winter" (PDF). Notornis. 37 (1): 1–23. Archived from the original (PDF) on 2009-03-26. Retrieved 2011-02-06.
- ↑ Arnold, Paula 1962. Birds of Israel. Shalit Publishers, Haifa, Israel. p17
- ↑ Botkin, D. B. (2001). "The naturalness of biological invasions". Western North American Naturalist. 61 (3): 261–266.
- ↑ Seedikkoya K; PA Azeez; EA Abdul Shukkur (2007). "Cattle egret as a biocontrol agent" (PDF). Zoos' Print Journal. 22 (10): 2864–2866. doi:10.11609/JoTT.ZPJ.1731.2864-6. Archived from the original (PDF) on 2011-09-29. Retrieved 2011-02-06.
- ↑ Siegfried, W. R. (1971). "The Food of the Cattle Egret". Journal of Applied Ecology. British Ecological Society. 8 (2): 447–468. doi:10.2307/2402882. JSTOR 2402882.
- ↑ Fogarty, Michael J.; Hetrick, Willa Mae (1973). "Summer Foods of Cattle Egrets in North Central Florida". The Auk. 90 (2): 268–280.
- ↑ Grubb, T. (1976). "Adaptiveness of foraging in the cattle egret". Wilson Bulletin. 88 (1): 145–148.
- ↑ Dinsmore, James J. (1973). "Foraging success of Cattle Egrets, Bubulcus ibis". American Midland Naturalist. The University of Notre Dame. 89 (1): 242–246. doi:10.2307/2424157. JSTOR 2424157.