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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 Caviahue

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: 589151
 
Caviahue
Neuquén
Argentina
04/05/2024
Adrian Braidotti
Foto
Photography ID: 582956
 
Caviahue
Neuquén
Argentina
04/05/2024
Adrian Braidotti
Foto
Photography ID: 582951
 
Caviahue
Neuquén
Argentina
04/05/2024
Adrian Braidotti
Foto
Photography ID: 525852
  Adult

Caviahue
Neuquén
Argentina
02/22/2023
Juan Manuel Canepa
Foto
Photography ID: 482842
  Juvenile

Caviahue
Neuquén
Argentina
02/02/2022
Cesar D Agostino
Foto
Photography ID: 338661
  Immature

Caviahue
Neuquén
Argentina
01/30/2019
Gustavo Abel Larracoechea
Foto
Photography ID: 256423
  Juvenile

Caviahue
Neuquén
Argentina
01/08/2018
Gonzalo Clifton Goldney



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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
202999005/04/2024ArgentinaNeuquénSendero a Puente de Piedra, CaviahueAdrian Braidotti
197661123/01/2024ArgentinaNeuquénSendero Cascada escondida, Caviahue1Rodolfo Domnanovich
175374402/03/2023ArgentinaNeuquénCaviahueGuillermo Marcaida
174865502/03/2023ArgentinaNeuquénCaviahueElsa Longo
172842922/02/2023ArgentinaNeuquénRío Agrio, CaviahueJuan Manuel Canepa
154801402/02/2022ArgentinaNeuquénSendero a Puente de Piedra, CaviahueCesar D Agostino
146280406/09/2021ArgentinaNeuquénCaviahue1Gabriel Carbajales
93645130/01/2019ArgentinaNeuquénCamino Caviahue-copahue, CaviahueGustavo Abel Larracoechea
87603908/01/2019ArgentinaNeuquénAnp Caviahue-copahue, CaviahueLuis Emilio Lorenzo
71431305/03/2018ArgentinaNeuquénOrillas del lago caviahue, CaviahueHugo Caverzasi
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 12/03/2026.