Geranoaetus albicaudatus (http://www.naturespicsonline.com/)
Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Archosauromorpha
Cladus: Crurotarsi
Divisio: Archosauria
Cladus: Avemetatarsalia
Cladus: Ornithodira
Subtaxon: Dinosauromorpha
Cladus: Dinosauriformes
Cladus: Dracohors
Cladus: Dinosauria
Ordo: Saurischia
Cladus: Eusaurischia
Subordo: Theropoda
Cladus: Neotheropoda
Cladus: Averostra
Cladus: Tetanurae
Cladus: Avetheropoda
Cladus: Coelurosauria
Cladus: Tyrannoraptora
Cladus: Maniraptoromorpha
Cladus: Maniraptoriformes
Cladus: Maniraptora
Cladus: Pennaraptora
Cladus: Paraves
Cladus: Eumaniraptora
Cladus: Avialae
Infraclassis: Aves
Cladus: Euavialae
Cladus: Avebrevicauda
Cladus: Pygostylia
Cladus: Ornithothoraces
Cladus: Ornithuromorpha
Cladus: Carinatae
Parvclassis: Neornithes
Cohors: Neognathae
Cladus: Neoaves
Ordo: Accipitriformes
Familia: Accipitridae
Subfamilia: Buteoninae
Genus: Geranoaetus
Species: Geranoaetus albicaudatus
Subspecies: G. a. albicaudatus - G. a. colonus - G. a. hypospodius
Name
Geranoaetus albicaudatus (Vieillot, 1816)
Synonyms
Buteo albicaudatus
References
Nouveau Dictionnaire d'Histoire Naturelle Appliquée Aux Arts, principalement à l'Agriculture et à l'Economie rurale et domestique par une société de naturalistes et d'agriculteurs, avec des figures tirées des trois règnes de la nature. 4 p.477
Vernacular names
čeština: Káně pestrá
English: White-tailed Hawk
español: Busardo coliblanco
magyar: Fehérszárnyú ölyv
polski: Myszołów białosterny
português: Gavião-de-rabo-branco
Türkçe: Ak kuyruklu şahin
The white-tailed hawk (Geranoaetus albicaudatus) is a large bird of prey species found in tropical and subtropical environments of the Americas.
Description
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 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, in particular individuals which 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 birds approach 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]
Call
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]
Subspecies
Three subspecies are known:[4]
Geranoaetus albicaudatus hypospodius – coastal Texas and the Rio Grande Valley[5] through Middle America to northern Colombia and western Venezuela.
Intermediate in size and coloration. No dark morph.
Geranoaetus albicaudatus colonus – Eastern Colombia to Surinam south to the mouth of the Amazon River, extending into the Caribbean.
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.
Geranoaetus albicaudatus albicaudatus – Southern Amazon rainforest to central Argentina
Large and dark; throat usually black (except in western Argentina). The dark morph appears blackish above, blackish-brown below.
Distribution and ecology
Adult B. a. hypospodius at Laguna Atascosa National Wildlife Refuge, Texas, USA
Adult, SE Brazil
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 to soar. Generally, it prefers arid habitat 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 it 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]
Footnotes
BirdLife International (2020). "Geranoaetus albicaudatus". IUCN Red List of Threatened Species. 2020: e.T22695906A169001701. doi:10.2305/IUCN.UK.2020-3.RLTS.T22695906A169001701.en. Retrieved 19 November 2021.
Gill F, D Donsker & P Rasmussen (Eds). 2020. IOC World Bird List (v10.2). doi : 10.14344/IOC.ML.10.2.
Ferguson-Lees, J.; Christie, D. (2001). Raptors of the World. London: Christopher Helm. ISBN 0-7136-8026-1.
HCT (2008)
"White-tailed Hawk". The Birds of North America Online. Cornell Laboratory of Ornithology. Retrieved 2009-01-06.
Faria et al. (2006), BLI (2008)
Ragusa-Netto (2000)
eNature (2007), HCT (2008)
"Callithrix kuhlii (Weid's black-tufted-ear marmoset)".
References
eNature (2007): 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 PDF fulltext
Hawk Conservancy Trust (HCT) (2008): 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 PDF fulltext
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