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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: 589152
 
El Infiernillo
Tucumán
Argentina
08/08/2018
Adrian Braidotti
Foto
Photography ID: 485387
  Immature

San Carlos de Bariloche
Río Negro
Argentina
02/13/2018
Horacio Alberto Garcia
Foto
Photography ID: 481174
  Juvenile

San Carlos de Bariloche
Río Negro
Argentina
02/13/2018
Horacio Alberto Garcia
Foto
Photography ID: 459151
  Juvenile

Pampa de las Carreras
Mendoza
Argentina
03/08/2018
Iván Procheret
Foto
Photography ID: 390618
  Juvenile

Ruta 40
Santa Cruz
Argentina
03/31/2018
Zulima América Schupbach
Foto
Photography ID: 347160
 

Dique El Cadillal
Tucumán
Argentina
05/14/2018
Edgar Romeo
Foto
Photography ID: 329386
  Juvenile

Cercanías a Rucanelo
La Pampa
Argentina
10/14/2018
Juan Jose Tamagnone
Foto
Photography ID: 309449
  Juvenile

San Carlos de Bariloche
Río Negro
Argentina
12/24/2018
Iván Eroles
Foto
Photography ID: 308655
  Immature

Parque Nacional Talampaya
La Rioja
Argentina
11/17/2018
Elsa Longo



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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
86413531/12/2018ArgentinaRío NegroPlaya las conchillas, San Antonio Este5Adriana Bellotti
86171230/12/2018ArgentinaCórdobaParque Nacional Quebrada del Condorito1Enzo Rossi
105953128/12/2018ArgentinaRío NegroSan Antonio Oeste2Julian Quillen Vidoz
105952128/12/2018ArgentinaRío NegroCosta del Rio Colorado - Puente sobre Ruta 22, Pichi Mahuida2Julian Quillen Vidoz
86329128/12/2018ArgentinaRío NegroLas Grutas, Las Grutas2Mariano Costa
105953027/12/2018ArgentinaRío NegroSan Antonio Oeste4Julian Quillen Vidoz
105949227/12/2018ArgentinaChubutÁrea Natural Protegida Península Valdés6Julian Quillen Vidoz
105953426/12/2018ArgentinaChubutSarmiento y alrededores, Sarmiento6Julian Quillen Vidoz
85942625/12/2018ArgentinaSan LuisCerro Tomolasta, La CarolinaDiego Carus
105951124/12/2018ArgentinaChubutCamarones, Florentino Ameghino4Julian Quillen Vidoz
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.