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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 Caleta Olivia

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: 511658
  Adult

Caleta Olivia
Santa Cruz
Argentina
10/22/2022
Hugo Alberto Valderrey
Foto
Photography ID: 492772
  Adult

Caleta Olivia
Santa Cruz
Argentina
04/29/2022
Marcelo Allende
Foto
Photography ID: 393644
  Adult

Caleta Olivia
Santa Cruz
Argentina
03/17/2020
Jorge Schlemmer



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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
172721413/02/2023ArgentinaSanta CruzCaleta Olivia2Guillermo Enrique Rost
166249022/10/2022ArgentinaSanta CruzRuta 3 al sur de Caleta Olivia, Caleta OliviaHugo Alberto Valderrey
157845329/04/2022ArgentinaSanta CruzA orillas de ruta 3 entre Caleta Olivia y Comodoro Rivadavia, Caleta OliviaMarcelo Allende
155475305/03/2022ArgentinaSanta CruzPlayas de Caleta Olivia, Caleta Olivia3Guillermo Enrique Rost
123452717/03/2020ArgentinaSanta CruzRuta 3 al sur de Caleta Olivia, Caleta OliviaJorge Schlemmer
89124526/02/2019ArgentinaSanta CruzCaleta Olivia1Nicolas Olejnik
89121524/02/2019ArgentinaSanta CruzCaleta Olivia1Nicolas Olejnik
24257416/02/2015ArgentinaSanta CruzLaguna Lobería, Caleta OliviaGuillermo Enrique Rost
21941803/01/2015ArgentinaSanta CruzPlaya La Lobería, Caleta OliviaGuillermo Enrique Rost
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 13/03/2026.