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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: 599949
  Immature

Carmen de Patagones
Buenos Aires
Argentina
09/14/2024
Ricardo Juliano
Foto
Photography ID: 574519
  Immature

Faro Belen
Río Negro
Argentina
03/07/2024
Ricardo Juliano
Foto
Photography ID: 506489
  Adult

Faro Belen
Río Negro
Argentina
09/04/2022
Ricardo Juliano
Foto
Photography ID: 502605
  Adult

Faro Belen
Río Negro
Argentina
07/30/2022
Ricardo Juliano
Foto
Photography ID: 463118
  Adult

Faro Belen
Río Negro
Argentina
09/23/2021
Ricardo Juliano
Foto
Photography ID: 430209
  Adult

Mina Gonzalito
Río Negro
Argentina
01/16/2021
Ricardo Juliano
Foto
Photography ID: 430208
  Juvenile

Mina Gonzalito
Río Negro
Argentina
01/16/2021
Ricardo Juliano
Foto
Photography ID: 419969
  Adult

Ruta 23 km 400
Río Negro
Argentina
11/19/2020
Ricardo Juliano
Foto
Photography ID: 386904
  Adult

Ruta 3 km 760
Buenos Aires
Argentina
03/03/2020
Ricardo Juliano
Foto
Photography ID: 337888
  Adult

Andalgalá
Catamarca
Argentina
06/19/2019
Ricardo Juliano



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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
241505511/01/2026ArgentinaRío NegroFaro Belen, Adolfo AlsinaRicardo Juliano
234426918/08/202510:00ArgentinaBuenos AiresCamino de ingreso a Gorchs, Gorchs1Ricardo Juliano
225079423/02/2025ArgentinaRío NegroFaro Belen, Faro BelenRicardo Juliano
224093524/01/2025ArgentinaRío NegroEx Ruta 40 entre Alicurá y Ruta Nacional 23Ricardo Juliano
223957521/01/2025ArgentinaRío NegroRio pichi leufuRicardo Juliano
215102814/09/2024ArgentinaBuenos AiresCamino a Salina de Piedra, Carmen de PatagonesRicardo Juliano
200762107/03/2024ArgentinaRío NegroFaro Belen, Faro BelenRicardo Juliano
194860414/01/2024ArgentinaRío NegroFaro Belen, Faro BelenRicardo Juliano
179399718/07/2023ArgentinaRío NegroFaro Belen1Ricardo Juliano
170099002/01/2023ArgentinaRío NegroFaro Belen, Faro BelenRicardo Juliano
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 29/03/2026.