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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 Lobería

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: 338448
  Adult

Lobería
Buenos Aires
Argentina
06/22/2019
Susana Gomez
Foto
Photography ID: 338447
  Juvenile

Lobería
Buenos Aires
Argentina
06/22/2019
Susana Gomez
Foto
Photography ID: 338275
♂ ♀
  Adult

Lobería
Buenos Aires
Argentina
06/22/2019
Susana Gomez
Foto
Photography ID: 336858
  Adult

Lobería
Buenos Aires
Argentina
06/14/2019
Susana Gomez
Foto
Photography ID: 336158
  Juvenile

Lobería
Buenos Aires
Argentina
06/09/2019
Susana Gomez
Foto
Photography ID: 335567
  Adult

Lobería
Buenos Aires
Argentina
06/03/2019
Susana Gomez
Foto
Photography ID: 210013
♂ ♀
  Adult

Lobería
Buenos Aires
Argentina
07/13/2017
Susana Gomez
Foto
Photography ID: 204281
  Adult

Lobería
Buenos Aires
Argentina
05/30/2017
Edgar Romeo
Foto
Photography ID: 204279
  Adult

Lobería
Buenos Aires
Argentina
05/27/2017
Edgar Romeo



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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
231238420/06/2025ArgentinaBuenos AiresRuta Prov. 227, Lobería2Gabriel Carbajales
157534128/04/2022ArgentinaBuenos AiresCercanías de Pieres, Lobería1Santiago Juan Torres
145347503/07/2021ArgentinaBuenos AiresLoberíaHernán Tolosa
93519422/06/2019ArgentinaBuenos AiresCalles rurales, LoberíaSusana Gomez
93295514/06/2019ArgentinaBuenos AiresCercanías de Pieres, LoberíaSusana Gomez
93200009/06/2019ArgentinaBuenos AiresCalles rurales, LoberíaSusana Gomez
93012903/06/2019ArgentinaBuenos AiresCalles rurales, LoberíaSusana Gomez
59138013/07/2017ArgentinaBuenos AiresCercanías de Pieres, LoberíaSusana Gomez
57850930/05/2017ArgentinaBuenos AiresEntrada Arenas Verdes, LoberíaEdgar Romeo
57850727/05/2017ArgentinaBuenos AiresEntrada Arenas Verdes, LoberíaEdgar Romeo
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.