White-tailed hawk

The white-tailed hawk is a large, stocky hawk. It is similar in size to the Swainson's (Buteo swainsoni) and red-tailed hawks (Buteo jamaicensis), with mean measurements slightly larger than the former and slightly smaller than the latter. It can attain a total length of {{convert|44|-|60|cm|in|abbr=on}} and a wingspan of {{convert|118|-|143|cm|in|abbr=on}}. Body mass has been reported as {{convert|880|-|1240|g|lb|abbr=on}} (B. a. hysopodius) and {{convert|865|-|1010|g|lb|abbr=on}} (B. a. colonus). Standard measurements include a wing chord of {{convert|39|-|46.2|cm|in|abbr=on}}, a tail of {{convert|19.4|-|22|cm|in|abbr=on}}, and a tarsus of {{convert|8|-|9.2|cm|in|abbr=on}}.{{cite book|author=Ferguson-Lees, J.|author2=Christie, D.|year=2001|title=Raptors of the World| publisher=Christopher Helm|location=London|isbn=0-7136-8026-1}} Adult birds are grey above and white below and on the rump, with faint pale grey or rufous barring. The short tail is white with a narrow black band near the end that is conspicuous in flight. A rusty-red shoulder patch is also characteristic when the bird is perched with wings closed. The upperwings are dark, mixed with grey near the bases of the blackish primary remiges. The underwing is whitish, with indistinct brownish barring on the underwing coverts; this barring extends onto the flanks and thighs. The iris is hazel, the cere is pale green, the beak is black with a horn-colored base, and the feet are yellow with black talons.HCT (2008)

Immature birds are darker than adults; they may appear nearly black in poor light, particularly those with little white below. The wing lining is conspicuously spotted black-and-white; the rusty shoulder patch is absent in younger birds. The tail changes from brown with several dark bars to greyish with a hazy dark band as the bird approaches maturity. The bare parts are colored similar to the adult.

In the Southern Hemisphere winter, young birds are sometimes mistaken for migrant red-backed hawks (Geranoaetus polyosoma).

Its call is a high-pitched cackling ke ke ke..., with a tinkling quality that reminds some of the bleating of a goat or the call of the laughing gull.

Three subspecies are known:

File:White-tailed Hawk.jpg, Texas, USA]]

File:Buteo albicaudatus.jpg

The white-tailed hawk is found from the coastal of Texas and the Rio Grande Valley south to central Argentina. Its range also includes many Caribbean islands in the Lesser Antilles and Trinidad and Tobago. It prefers open or semi-open regions up to 2,000 ft (c. 600 m) ASL, with few trees to obstruct flight. It is not a migratory bird, though some populations may make regional movements when food is scarce. It commonly perches on bushes, trees, or telephone poles, stands on the ground, or engages in soar. Generally, it prefers arid habitats and rarely occurs in areas with heavy rainfall.

Though it may disappear from unsuitable locations following habitat fragmentation, it has a wide range and is not considered to be a globally threatened species by the IUCN.Faria et al. (2006), BLI (2008)

Its preferred hunting technique is to hover and observe the surroundings for signs of potential prey, gliding to another place when nothing is found. The diet of the white-tailed hawk varies with its environment. Rabbits make up the majority of the hawk's diet in southern Texas, while lizards 12 in (30 cm) or more in length are preferred prey in the Dutch West Indies. Other animals such as cotton rats, snakes, frogs, arthropods (especially grasshoppers, cicadas, and beetles), and small birds like passerines or quails are also eaten; it may take chickens if no other food source is available. In the open cerrado of Brazil, mixed-species feeding flocks react to white-tailed hawks with almost as much alarm as they do to dedicated bird predators such as the aplomado falcon.Ragusa-Netto (2000) The white-tailed hawk is also known to feed on carrion and to gather with other birds at brushfires to catch small animals fleeing the flames.eNature (2007), HCT (2008) In the tropics, white-tailed hawks rank amongst the main predators of the small monkeys known as marmosets.{{Cite web|url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Callithrix_kuhlii.html|title = Callithrix kuhlii (Weid's black-tufted-ear marmoset)}}

Breeding pairs build nests from freshly broken twigs, often from thorny plants. Nests are typically placed 5–15 ft (1.5–5 m) or more above the ground in a tree or yucca, preferably in an elevated location offering good visibility from the nest. The interior is cushioned with dried grasses and other fine materials; green twigs of mesquite or other aromatic plants are often added, perhaps to deter parasites. Like many Accipitridae, white-tailed hawks tend to reuse nest sites. Nests built up over the years can thus reach sizes of up to 3 ft (1 m) across. The eggs are white, often lightly spotted with brown or lavender; between one and three (usually two) are laid per clutch. When approached at the nest, adults become airborne and observe the intruder from above. This contrasts with related hawks, which typically wait longer before flushing and may launch direct attacks.

{{Reflist}}

• eNature (2007): [http://www.enature.com/flashcard/show_flash_card.asp?recordNumber=BD0556 White-tailed Hawk]. Retrieved 2008-NOV-19.
• Faria, Christiana M.A.; Rodrigues, Marcos; do Amaral, Frederico Q.; Módena, Érica & Fernandes, Alexandre M. (2006): Aves de um fragmento de Mata Atlântica no alto Rio Doce, Minas Gerais: colonização e extinção [The birds of an Atlantic Forest fragment at upper Rio Doce valley, Minas Gerais, southeastern Brazil: colonization and extinction]. Revista Brasileira de Zoologia 23(4): 1217-1230 [Portuguese with English abstract]. {{doi|10.1590/S0101-81752006000400032}} [http://www.scielo.br/pdf/rbzool/v23n4/32.pdf PDF fulltext]
• Hawk Conservancy Trust (HCT) (2008): [http://www.hawk-conservancy.org/priors/whitetailedhawk.shtml White-tailed Hawk – Buteo albicaudatus]. Version of 2008-NOV-19. Retrieved 2008-NOV-19.
• Ragusa-Netto, J. (2000): Raptors and "campo-cerrado" bird mixed flock led by Cypsnagra hirundinacea (Emberizidae: Thraupinae). Revista Brasileira de Biologia 60(3): 461-467 [English with Portuguese abstract]. {{doi|10.1590/S0034-71082000000300011}} {{PMID|11188872}} [http://www.scielo.br/pdf/rbbio/v60n3/3933.pdf PDF fulltext]

{{Commons category|Geranoaetus albicaudatus}}

{{Wikispecies|Geranoaetus albicaudatus}}

• [http://www.enature.com/fieldguides/detail.asp?recNum=BD0556 White-tailed hawk Information] eNature.com

{{Buteoninae}}

{{Taxonbar|from=Q997713}}

white-tailed hawk

white-tailed hawk

Category:Birds of the Rio Grande valleys

Category:Birds of Central America

Category:Birds of South America

Category:Birds of the Caribbean

Category:Birds of prey of the Americas

white-tailed hawk

white-tailed hawk