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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: 636189
  Juvenile

Parque Nacional los Cardones
Salta
Argentina
05/13/2025
Dolores Fernandez
Foto
Photography ID: 441290
  Adult

Garayalde
Chubut
Argentina
03/25/2021
Dolores Fernandez
Foto
Photography ID: 387500
  Adult

Puerto Madryn
Chubut
Argentina
03/01/2020
Dolores Fernandez
Foto
Photography ID: 326132
  Adult

General Conesa
Buenos Aires
Argentina
03/03/2019
Dolores Fernandez
Foto
Photography ID: 253746
  Immature

Puerto Madryn
Chubut
Argentina
03/07/2018
Dolores Fernandez
Foto
Photography ID: 214071
  Immature

Ruta Provincial 20
San Luis
Argentina
08/06/2017
Dolores Fernandez
Foto
Photography ID: 203375
  Adult

Abra Pampa
Jujuy
Argentina
04/24/2017
Dolores Fernandez
Foto
Photography ID: 202102
  Juvenile

Ruta 9
Jujuy
Argentina
04/23/2017
Dolores Fernandez
Foto
Photography ID: 202082
  Adult

Azul Pampa
Jujuy
Argentina
04/23/2017
Dolores Fernandez



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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
243818415/02/2026ArgentinaChubutÁrea Natural Protegida Península ValdésDolores Fernandez
243621515/02/202609:08ArgentinaRío NegroRuta Nacional 3Dolores Fernandez
229286713/05/2025ArgentinaSaltaParque Nacional los CardonesDolores Fernandez
219551618/11/2024ArgentinaNeuquénParque Provincial El TromenDolores Fernandez
203374209/05/2024ArgentinaJujuyAzul PampaDolores Fernandez
198020925/02/2024ArgentinaChubutRuta 25 entre Gaiman y Tecka, EsquelDolores Fernandez
197806724/02/2024ArgentinaRío NegroRuta Nacional 3Dolores Fernandez
176350310/05/2023ArgentinaSan LuisEl Filo, Villa de MerloDolores Fernandez
176333209/05/2023ArgentinaSan LuisRuta Provincial 5Dolores Fernandez
167904025/11/2022ArgentinaNeuquénParque Provincial El TromenDolores Fernandez
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 06/04/2026.