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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: 532665
  Adult

Yacimiento El Trapial
Neuquén
Argentina
04/18/2023
Diego Alfonso Rosa
Foto
Photography ID: 509527
  Adult

Villa de Merlo
San Luis
Argentina
09/03/2022
Diego Alfonso Rosa
Foto
Photography ID: 509119
  Adult

Parque Nacional Talampaya
La Rioja
Argentina
09/05/2022
Diego Alfonso Rosa
Foto
Photography ID: 484085
  Adult

Villa Pehuenia
Neuquén
Argentina
02/01/2022
Diego Alfonso Rosa
Foto
Photography ID: 173635
  Adult

Yacimiento Coiron Amargo
Neuquén
Argentina
10/31/2016
Diego Alfonso Rosa
Foto
Photography ID: 155072
  Juvenile

Catriel
Río Negro
Argentina
11/19/2014
Diego Alfonso Rosa
Foto
Photography ID: 155068
  Adult

Bajada del Toro
Neuquén
Argentina
06/23/2016
Diego Alfonso Rosa



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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
175515918/04/2023ArgentinaNeuquénYacimiento El TrapialDiego Alfonso Rosa
164705105/09/2022ArgentinaLa RiojaParque Nacional TalampayaDiego Alfonso Rosa
164842603/09/2022ArgentinaSan LuisMirador de los condores, Villa de MerloDiego Alfonso Rosa
155201801/02/2022ArgentinaNeuquénPunta Negra, Villa PehueniaDiego Alfonso Rosa
49905131/10/2016ArgentinaNeuquénYacimiento Coiron AmargoDiego Alfonso Rosa
44705423/06/2016ArgentinaNeuquénBajada del ToroDiego Alfonso Rosa
44705501/02/2015ArgentinaChubutCamino entre Corcovado y Lago Vintter., Camino entre Corcovado y Lago VintterDiego Alfonso Rosa
44705819/11/2014ArgentinaRío NegroPuesto Morales, CatrielDiego Alfonso Rosa
44705717/02/2011ArgentinaChubutÁrea Natural Protegida Península ValdésDiego Alfonso Rosa
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 11/04/2026.