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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: 670586
 
Santa María
Catamarca
Argentina
05/16/2014
Viviana Fuentes
Foto
Photography ID: 642456
  Adult

Carro Quemado
La Pampa
Argentina
08/01/2014
Fernando Rasmussen
Foto
Photography ID: 642454
  Adult

Carro Quemado
La Pampa
Argentina
08/01/2014
Fernando Rasmussen
Foto
Photography ID: 338659
♂ ♀
  Adult

Punta Alta
Buenos Aires
Argentina
07/09/2014
Gustavo Abel Larracoechea
Foto
Photography ID: 260491
  Adult

Sierra de Santa barbara
Jujuy
Argentina
07/23/2014
Vicente Piccirillo
Foto
Photography ID: 242145
  Adult

Ruta 1 km 45
Chubut
Argentina
02/09/2014
Zulima América Schupbach
Foto
Photography ID: 229731
  Juvenile

Trelew
Chubut
Argentina
05/02/2014
Zulima América Schupbach
Foto
Photography ID: 209458
  Adult

Bowen
Mendoza
Argentina
03/30/2014
Feliciano Ferretti
Foto
Photography ID: 197727
  Juvenile

Camino de los Puentes Colgantes
Córdoba
Argentina
08/31/2014
Jorge Schlemmer
Foto
Photography ID: 164079
  Adult

Parque Nacional Cotopaxi
Cotopaxi
Ecuador
09/29/2014
Carmelo López Abad
Foto
Photography ID: 155072
  Juvenile

Catriel
Río Negro
Argentina
11/19/2014
Diego Alfonso Rosa
Foto
Photography ID: 152637
  Juvenile

Los Antiguos
Santa Cruz
Argentina
06/19/2014
Eduardo Militello



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Last Vocalizations published



Audio playerUserDateCountryProvincePlaceSexLife stageIt was observedDetails
Santiago Sainz-trápaga04/29/2014ArgentinaChubutPunta DelgadaÁrea Natural Protegida Península ValdésIndistinguishableJuvenileYesNo



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Last Filmings published




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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
21642931/12/2014ArgentinaRío NegroCerro Catedral, San Carlos de BarilocheDiana Weyland
21477328/12/2014ArgentinaRío NegroRuta 251Diego Oscar
105950525/12/2014ArgentinaChubutLeleque, CushamenJulian Quillen Vidoz
21290023/12/2014ArgentinaChubut40 km al sur de Camarones, Ruta Provincial N°1Ricardo Juliano
44383008/12/2014ArgentinaCórdobaParque Nacional Quebrada del CondoritoFernando Alberto Segura
22675108/12/2014ArgentinaChubutCamaronesMax Uranga
24494707/12/2014ArgentinaLa Pampapor distintas zonas en la periferia del parque, Reserva Provincial Parque LuroCarina Benente
21797205/12/2014ArgentinaMendozaQuebrada de Horcones, Parque Provincial AconcaguaPablo Isola
20645904/12/2014ArgentinaChubutCamaronesMariano Costa
20641603/12/2014ChileRegión de ValparaísoCaracoles libertadoresCarlos Schmidt
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 16/03/2026.