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Variable Hawk

Geranoaetus polyosoma
(Quoy, JRC; Gaimard, JP, 1824)
Aguilucho Común
Gavião-de-costas-vermelhas

Family: Accipitridae
Order: Accipitriformes
Class: Aves
Phylum / Division: Chordata
Kingdom: Animalia

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Conservation status according to BirdLife International: Least Concern

Other common names: Ñanco, Aguilucho Variable.

Synonyms: Buteo polyosoma, Falco polyosoma.

Subspecies:


Description: It is a large, long-winged raptor with a slender profile and remarkable plumage variability. Individuals range from mostly ash-gray to rufous or chestnut tones, with lighter or darker underparts depending on morph. In flight, it is recognized by its slightly raised wings forming a shallow “V”, relatively short tail, and pale patches at the base of the primaries. Juveniles tend to be browner and more streaked.

Geographic distribution: It is widely distributed across South America, from southern Colombia and Venezuela to southernmost Chile and Argentina. It is especially common along the Andes, but also inhabits Patagonian steppes, intermontane valleys, and open lowlands.

Habitat: It occupies open and semi-open habitats, including grasslands, shrublands, agricultural areas, and mountainous regions. It tolerates a broad altitudinal range, from sea level to over 4,000 m, efficiently using thermal currents for soaring.

Diet: It is an opportunistic predator, feeding mainly on small mammals (particularly rodents), medium-sized birds, reptiles, and large insects. It also scavenges when opportunities arise, which increases its dietary flexibility.

Behavior: Usually seen alone or in pairs, though it may gather where food is abundant. It spends long periods soaring with a powerful yet economical flight, and maintains large territories during the breeding season.

Nesting: It builds large stick nests, typically on rocky cliffs, escarpments, or occasionally tall trees and human-made structures. Clutches usually consist of one to two eggs, with shared parental care and an extended fledging period.

Conservation status: It is classified as Least Concern globally due to its wide range and generally stable populations, although local threats include persecution, electrocution, and habitat alteration.


Author of this compilation: EcoRegistros – 15/12/2025




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Last published photographs

Foto
Photography ID: 111432
  Juvenile

Pieres
Buenos Aires
Argentina
08/26/2015
Santiago Juan Torres
Foto
Photography ID: 70474
  Adult

Villa La Angostura
Neuquén
Argentina
11/26/2014
Santiago Juan Torres
Foto
Photography ID: 56641
  Adult

Yatasto
Salta
Argentina
07/14/2014
Santiago Juan Torres
Foto
Photography ID: 54486
  Adult

Tornquist
Buenos Aires
Argentina
06/20/2014
Santiago Juan Torres
Foto
Photography ID: 41835
  Adult

Ruta 18
La Pampa
Argentina
03/04/2014
Santiago Juan Torres
Foto
Photography ID: 23424
  Adult

Cerro Champaquí
Córdoba
Argentina
06/22/2013
Santiago Juan Torres
Foto
Photography ID: 20202
  Immature

Bajo Caracoles
Santa Cruz
Argentina
02/14/2012
Santiago Juan Torres



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 Reports


 Detail of places sorted by number of records








Page 1
Record IDDateExact timeCountryProvince / departmentPlaceFilmedPhotographedRecorded vocalObservedHeardWounded or deadNumber of individualsUser or BibliographyDetail
244106301/03/202611:55ArgentinaBuenos AiresRuta Provincial 2271Santiago Juan Torres
233267902/08/202512:48ArgentinaTucumánRuta Nacional 1571Santiago Juan Torres
233185701/08/202517:19ArgentinaTucumánRuta Provincial 307, Tafí del Valle2Santiago Juan Torres
233183001/08/202514:04ArgentinaCatamarcaRuta Nacional 401Santiago Juan Torres
232769428/07/202509:14ArgentinaCatamarcaRuta Nacional 601Santiago Juan Torres
232594625/07/202518:08ArgentinaSan LuisRuta Nacional 1481Santiago Juan Torres
232593825/07/202517:57ArgentinaSan LuisRuta Nacional 148 6951Santiago Juan Torres
232592825/07/202517:11ArgentinaSan LuisRuta Nacional 1481Santiago Juan Torres
232592625/07/202517:09ArgentinaSan LuisRuta Nacional 1481Santiago Juan Torres
232591925/07/202517:02ArgentinaSan LuisRuta Nacional 1481Santiago Juan Torres
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 19/03/2026.