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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 Bahía Blanca

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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Latest feeding records




Last published photographs

Foto
Photography ID: 537218
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
06/08/2023
Lucas Martín
Foto
Photography ID: 494977
  Adult

Bahía Blanca
Buenos Aires
Argentina
05/22/2022
Lucas Martín
Foto
Photography ID: 493222
  Adult

Bahía Blanca
Buenos Aires
Argentina
05/07/2022
Lucas Martín
Foto
Photography ID: 451124
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
06/20/2021
Diego Hernán Pérez
Foto
Photography ID: 442529
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
04/22/2021
Lucas Martín
Foto
Photography ID: 407187
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
07/09/2019
Diego Hernán Pérez
Foto
Photography ID: 361228
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
07/03/2019
Fernando Naifleisch
Foto
Photography ID: 339296
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
06/30/2019
Diego Hernán Pérez
Foto
Photography ID: 324922
  Juvenile

Bahía Blanca
Buenos Aires
Argentina
03/23/2019
Diego Hernán Pérez
Foto
Photography ID: 168442
  Adult

Bahía Blanca
Buenos Aires
Argentina
08/29/2016
Roberto Battaglia
Foto
Photography ID: 98906
  Adult

Bahía Blanca
Buenos Aires
Argentina
04/19/2015
Gustavo Kin



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Last Vocalizations 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
177576408/06/2023ArgentinaBuenos AiresCueva de los Leones (2 Km al N del cruce R 33 y Cam. Sesquicentenario, por R 33), Bahía BlancaLucas Martín
176567014/05/2023ArgentinaBuenos AiresPuerto Ingeniero White, Bahía Blanca1Susana Gomez
158699022/05/2022ArgentinaBuenos AiresPredio Conicet, Bahía BlancaLucas Martín
157997607/05/2022ArgentinaBuenos AiresCueva de los Leones (2 Km al N del cruce R 33 y Cam. Sesquicentenario, por R 33), Bahía BlancaLucas Martín
141872920/06/2021ArgentinaBuenos AiresBarrio La Huella, Bahía BlancaDiego Hernán Pérez
139704422/04/2021ArgentinaBuenos AiresPredio Conicet, Bahía BlancaLucas Martín
127870509/07/2019ArgentinaBuenos AiresBarrio La Huella, Bahía BlancaDiego Hernán Pérez
112781603/07/2019ArgentinaBuenos AiresBarrio La Huella, Bahía BlancaFernando Naifleisch
93871030/06/2019ArgentinaBuenos AiresBahía BlancaDiego Hernán Pérez
93177523/03/2019ArgentinaBuenos AiresArroyo sauce chico, Bahía BlancaDiego Hernán Pérez
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 14/03/2026.