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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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Records from Sierras de los Comechingones

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: 647551
  Adult

Sierras de los Comechingones
San Luis
Argentina
06/04/2025
Guillermo Marcaida
Foto
Photography ID: 646593
  Adult

Sierras de los Comechingones
San Luis
Argentina
06/04/2025
Elsa Longo
Foto
Photography ID: 27516
  Adult

Sierras de los Comechingones
San Luis
Argentina
09/28/2013
Jorge Omar Lanza
Foto
Photography ID: 27514
  Juvenile

Sierras de los Comechingones
San Luis
Argentina
09/28/2013
Jorge Omar Lanza
Foto
Photography ID: 27513
  Juvenile

Sierras de los Comechingones
San Luis
Argentina
09/28/2013
Jorge Omar Lanza



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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
234031304/06/2025ArgentinaSan LuisCamino del filo, Merlo, Sierras de los ComechingonesGuillermo Marcaida
233391904/06/2025ArgentinaSan LuisEl filo, Sierras de los ComechingonesElsa Longo
29323608/06/2015ArgentinaSan LuisCamino del filo, Merlo, Sierras de los ComechingonesNicolas Olejnik
7433228/09/2013ArgentinaSan LuisSierras de los ComechingonesJorge Omar Lanza
2132217/09/2011ArgentinaSan LuisSierras de los ComechingonesNicolas Olejnik
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 11/03/2026.