White-tailed hawk | |
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Adult at Salvador Zoo, Ondina, Salvador, Bahia, Brazil | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Accipitriformes |
Family: | Accipitridae |
Genus: | Geranoaetus |
Species: | G. albicaudatus |
Binomial name | |
Geranoaetus albicaudatus (Vieillot, 1816) | |
Subspecies [2] | |
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Synonyms | |
Buteo albicaudatus |
The white-tailed hawk (Geranoaetus albicaudatus) is a large bird of prey species found in tropical and subtropical environments of the Americas.
The white-tailed hawk is a large, stocky hawk. It is close in size to the Swainson's (Buteo swainsoni) and red-tailed hawks (Buteo jamaicensis), its mean measurements falling slightly ahead of the first, and slightly behind the latter. It can attain a total length of 44–60 cm (17–24 in) and a wingspan of 118–143 cm (46–56 in). A body mass of 880–1,240 g (1.94–2.73 lb) was reported in B. a. hysopodius and 865–1,010 g (1.907–2.227 lb) in B. a. colonus. Among standard measurements, the wing chord is 39–46.2 cm (15.4–18.2 in), the tail is 19.4–22 cm (7.6–8.7 in) and the tarsus is 8–9.2 cm (3.1–3.6 in). [3] 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 just as characteristic when the bird is sitting with its wings closed. The wings are dark above, admixed with grey near the bases of the blackish primary remiges. The underwing is whitish, with indistinct brownish barring on the underwing coverts, that 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. [4]
Immature birds are somewhat darker than adults; they may appear nearly black in faint light, particularly individuals who have 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 much like in the adult. [4]
In the Southern Hemisphere winter, young birds are sometimes mistaken for migrant red-backed hawks (Geranoaetus polyosoma). [4]
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. [4]
Three subspecies are known: [4]
Image | Subspecies | Description | Distribution |
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Geranoaetus albicaudatus hypospodius | Intermediate in size and coloration. No dark morph. | coastal Texas and the Rio Grande Valley [5] through Middle America to northern Colombia and western Venezuela. | |
Geranoaetus albicaudatus colonus | Small and pale. Dark morph is ashy grey all over, except for the tail and underwing coverts; sometimes extensively marked rufous on the underside. Dark-morph immatures are sometimes black all over, except for the tail. | Eastern Colombia to Suriname south to the mouth of the Amazon River, extending into the Caribbean. | |
Geranoaetus albicaudatus albicaudatus | Large and dark; throat usually black (except in western Argentina). The dark morph appears blackish above, blackish-brown below. | Southern Amazon rainforest to central Argentina | |
The white-tailed hawk can be found anywhere from coastal Texas and the Rio Grande Valley [5] to central Argentina, as well as many Caribbean islands of the Lesser Antilles, and Trinidad and Tobago. For habitat, it prefers open or semi-open regions up to 2,000 ft (c. 600 m) ASL, with few trees to hinder its flight. It is not a migratory bird, though some populations may make regional movements when food is scarce. It likes to perch on bushes, trees, telephone poles, or even stand around on the ground, as well as soar. Generally, it prefers arid habitats and rarely occurs in very rainy locales. [4]
Though it will disappear from unsuitable locations after habitat fragmentation, it has a wide range and is not considered to be a globally threatened species by the IUCN. [6]
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 of 12 in (30 cm) in length and more are the preferred prey in the Dutch West Indies. Other animals such as cotton rats, snakes, frogs, arthropods (especially grasshoppers, cicadas, and beetles), and smallish birds such as passerines or quails are also eaten; it will snatch chickens when no other source of food is available. In the open cerrado of Brazil, mixed-species feeding flocks will react to a white-tailed hawk with almost as much alarm as they do when seeing such dedicated predators of birds as the aplomado falcon. [7] 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. [8] In the tropics, white-tailed hawks rank amongst the main predators of the small monkeys known as marmosets. [9]
Breeding pairs of white-tailed hawks build nests out of freshly broken twigs, often of thorny plants, 5–15 ft (1.5–5 m) or more above the ground on top of a tree or yucca, preferably one growing in an elevated location giving good visibility from the nest. The nest's interior is cushioned with dried grasses and other fine materials; green twigs of mesquite or other aromatic plants are often placed in the nest too, perhaps to deter parasites. Like many Accipitridae, white-tailed hawks do not like to abandon a nest site, and nests built up over the years can thus reach sizes of up to three feet (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 on the nest, the adults will get airborne and observe the intruder from above, unlike related hawks, which usually wait much longer to flush and then launch a determined attack. [4]
Buteo is a genus of medium to fairly large, wide-ranging raptors with a robust body and broad wings. In the Old World, members of this genus are called "buzzards", but "hawk" is used in the New World. As both terms are ambiguous, buteo is sometimes used instead, for example, by the Peregrine Fund.
Buzzard is the common name of several species of birds of prey.
The rough-legged buzzard (Europe) or rough-legged hawk is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America, Europe, and Russia during the breeding season and migrates south for the winter. It was traditionally also known as the rough-legged falcon in such works as John James Audubon's The Birds of America.
The ferruginous hawk is a large bird of prey and belongs to the broad-winged buteo hawks. An old colloquial name is ferrugineous rough-leg, due to its similarity to the closely related rough-legged hawk.
The lizard buzzard, or lizard hawk, is a bird of prey in the family Accipitridae. It is native to Sub-Saharan Africa. Despite its name, it may be more closely related to the Accipiter hawks than the Buteo buzzards.
Harris's hawk, formerly known as the bay-winged hawk, dusky hawk, and sometimes a wolf hawk, and known in Latin America as peuco, is a medium-large bird of prey that breeds from the southwestern United States south to Chile, central Argentina, and Brazil. This bird is sometimes reported to be at large in Western Europe, especially Britain, but it is a popular species in falconry and these records almost invariably all refer to escapes from captivity.
The zone-tailed hawk is a medium-sized hawk of warm, dry parts of the Americas. It is somewhat similar in plumage and flight style to a common scavenger, the turkey vulture, and may benefit from being able to blend into groups of vultures. It feeds on small terrestrial tetrapods of all kinds.
The white hawk is a bird of prey breeding in the tropical New World of the family Accipitridae. Though it is commonly placed in the subfamily Buteoninae, the validity of this group is doubtful and currently under review.
The Galápagos hawk is a large hawk endemic to most of the Galápagos Islands.
The southern beardless tyrannulet is a small passerine bird in the tyrant flycatcher family. It breeds from Costa Rica through South America south to Paraguay, Bolivia, and Argentina.
The roadside hawk is a relatively small bird of prey found in the Americas. This vocal species is often the most common raptor in its range. It has many subspecies and is now usually placed in the monotypic genus Rupornis instead of Buteo.
The black-chested buzzard-eagle is a bird of prey of the hawk and eagle family (Accipitridae). It lives in open regions of South America. This species is also known as the black buzzard-eagle, the gray buzzard-eagle, or analogously with "eagle" or "eagle-buzzard" replacing "buzzard-eagle", or as the Chilean blue eagle. It is sometimes placed in the genus Buteo.
The curl-crested jay is a jay from South America.
The jackal buzzard is a fairly large African bird of prey. The taxonomy of this species has caused some confusion in the past and it almost certainly belongs in a species complex with other African Buteo species. Some taxonomists have considered this species, the Archer's buzzard, and the augur buzzard to be the same superspecies. Many taxonomists consider them all to be distinct, having different calls, different home ranges and variations in plumage. This is a species that lives among mountains, and on adjacent savanna and grassland. It is resident and non-migratory throughout its range.
The augur buzzard is a fairly large African bird of prey. This species is distinct in typical adult plumage for its blackish back, whitish underside and orange-red tail, while juvenile augur buzzards are generally rather brown in colour; however a dark morph is known, which causes the bird's entire body to become darker. This member of the Buteo genus is distributed in several parts of the central and southern Africa, normally being found from Ethiopia to southern Angola and central Namibia. It is resident and non-migratory throughout its range. This is a species of mountains, and adjacent savannah and grassland. This is a typical buteonine raptor, being a generalist predator which tends to prefer small mammals supplemented by reptiles and birds among various prey items.
The mountain buzzard is a bird of prey that lives in montane forests in East Africa, it and the forest buzzard of southern Africa were, until recently, considered to be a single species.
The black-and-white hawk-eagle is a bird of prey species in the eagle and hawk family (Accipitridae). It is found throughout a large part of tropical America, from southern Mexico to northern Argentina.
The variable hawk is a polymorphic species of bird of prey in the family Accipitridae.
The gray hawk or Mexican goshawk is a smallish raptor found in open country and forest edges. It is sometimes placed in the genus Asturina as Asturina plagiata. The species was split by the American Ornithological Society (AOU) from the gray-lined hawk. The gray hawk is found from Costa Rica north into the southwestern United States.
The short-tailed hawk is an American bird of prey in the family Accipitridae, which also includes the eagles and Old World vultures. As a member of the genus Buteo, it is not a true hawk and thus also referred to as a "buteo" or "buzzard". The white-throated hawk is a close relative and was formerly included in the species B. brachyurus.