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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 Las Grutas

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: 666229
  Adult

Las Grutas
Río Negro
Argentina
10/05/2025
Gustavo Abel Larracoechea
Foto
Photography ID: 631383
  Adult

Las Grutas
Río Negro
Argentina
03/27/2025
Carlos De Biagi
Foto
Photography ID: 619794
  Juvenile

Las Grutas
Río Negro
Argentina
01/02/2025
Claudio Javier Spiga
Foto
Photography ID: 576920
♂ ♀
  Adult

Las Grutas
Río Negro
Argentina
03/14/2024
Hugo Alberto Valderrey
Foto
Photography ID: 555037
  Juvenile

Las Grutas
Río Negro
Argentina
10/27/2023
Gustavo Daniel González
Foto
Photography ID: 488262
  Adult

Las Grutas
Río Negro
Argentina
03/05/2022
Carlos De Biagi
Foto
Photography ID: 484415
  Adult

Las Grutas
Río Negro
Argentina
11/29/2021
Elsa Longo
Foto
Photography ID: 385783
  Adult

Las Grutas
Río Negro
Argentina
02/17/2020
Carlos De Biagi
Foto
Photography ID: 375429
  Adult

Las Grutas
Río Negro
Argentina
01/14/2020
Andrés Cecconi
Foto
Photography ID: 118210
  Juvenile

Las Grutas
Río Negro
Argentina
08/14/2015
Jorge La Grotteria
Foto
Photography ID: 116068
  Fledgling

Las Grutas
Río Negro
Argentina
09/23/2015
Roberto Battaglia
Foto
Photography ID: 116067
  Juvenile

Las Grutas
Río Negro
Argentina
09/23/2015
Roberto Battaglia



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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
241247212/12/2025ArgentinaRío NegroLas Grutas, Las GrutasHernán Tolosa
239965812/12/2025ArgentinaRío NegroLas Grutas, Las GrutasJorgelina Lopez
241140705/10/2025ArgentinaRío NegroCamino a Piedras Coloradas, Las GrutasGustavo Abel Larracoechea
227678527/03/2025ArgentinaRío NegroCamping Oasis, Las GrutasCarlos De Biagi
223992102/01/2025ArgentinaRío NegroLas GrutasClaudio Javier Spiga
201264214/03/2024ArgentinaRío NegroLas Grutas, Las GrutasHugo Alberto Valderrey
190809127/10/2023ArgentinaRío NegroLas GrutasGustavo Daniel González
178445720/06/2023ArgentinaRío NegroLas Grutas2Aluminé Sangorrín
176663226/04/2023ArgentinaRío NegroLas Grutas, Las GrutasAdrian Braidotti
172325903/02/2023ArgentinaRío NegroLas Grutas, Las Grutas1Gabriel Carbajales
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.