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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: 217217
  Adult

Parque Nacional los Cardones
Salta
Argentina
08/21/2017
Claudio Mendez
Foto
Photography ID: 217212
  Adult

Tafí del Valle
Tucumán
Argentina
08/18/2017
Claudio Mendez
Foto
Photography ID: 216219
  Adult

Parque Nacional los Cardones
Salta
Argentina
08/21/2017
Claudio Mendez
Foto
Photography ID: 29544
  Juvenile

Chacharramendi
La Pampa
Argentina
11/11/2013
Claudio Mendez



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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
163937106/09/2022ArgentinaSan LuisFilo, Merlo1Claudio Mendez
159693124/05/2022ArgentinaSanta CruzParque PatagoniaClaudio Mendez
60680421/08/2017ArgentinaSaltaValle Encantado, Parque Nacional los CardonesClaudio Mendez
60837118/08/2017ArgentinaTucumánCamino al Infiernillo, Tafí del ValleClaudio Mendez
61402515/08/2017ArgentinaTucumánDique La Angostura, Tafí del Valle1Claudio Mendez
8416516/11/2013ArgentinaNeuquénLago HuechulafquenClaudio Mendez
8006711/11/2013ArgentinaLa PampaChacharramendiClaudio Mendez
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.