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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 Trelew

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: 453068
  Adult

Trelew
Chubut
Argentina
06/29/2021
Zulima América Schupbach
Foto
Photography ID: 391300
  Adult

Trelew
Chubut
Argentina
02/08/2020
Roberto Battaglia
Foto
Photography ID: 386172
  Adult

Trelew
Chubut
Argentina
02/08/2020
Roberto Battaglia
Foto
Photography ID: 381651
  Immature

Trelew
Chubut
Argentina
02/08/2020
Zulima América Schupbach
Foto
Photography ID: 381650
  Adult

Trelew
Chubut
Argentina
02/08/2020
Zulima América Schupbach
Foto
Photography ID: 381649
  Adult

Trelew
Chubut
Argentina
02/08/2020
Zulima América Schupbach
Foto
Photography ID: 381559
  Immature

Trelew
Chubut
Argentina
02/08/2020
Zulima América Schupbach
Foto
Photography ID: 381558
  Adult

Trelew
Chubut
Argentina
02/08/2020
Zulima América Schupbach
Foto
Photography ID: 381553
  Fledgling

Trelew
Chubut
Argentina
02/08/2020
Zulima América Schupbach
Foto
Photography ID: 376847
  Adult

Trelew
Chubut
Argentina
01/23/2020
Zulima América Schupbach
Foto
Photography ID: 376845
  Adult

Trelew
Chubut
Argentina
01/23/2020
Zulima América Schupbach
Foto
Photography ID: 322894
  Juvenile

Trelew
Chubut
Argentina
02/24/2019
Zulima América Schupbach



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Page 1
Record IDDateExact timeCountryProvince / departmentPlaceFilmedPhotographedRecorded vocalObservedHeardWounded or deadNumber of individualsUser or BibliographyDetail
142475829/06/2021ArgentinaChubutArea de Fitorremediación, Trelew1Zulima América Schupbach
120656908/02/2020ArgentinaChubutRuta Provincial 1 de Trelew a isla Escondida, TrelewRoberto Battaglia
119147108/02/2020ArgentinaChubutRuta Provincial 1 de Trelew a isla Escondida, TrelewZulima América Schupbach
117635323/01/2020ArgentinaChubutRuta Provincial 1 de Trelew a isla Escondida, TrelewZulima América Schupbach
89823424/02/2019ArgentinaChubutRuta Provincial 1 de Trelew a isla Escondida, TrelewZulima América Schupbach
64503202/05/2014ArgentinaChubutRuta Provincial 1 de Trelew a isla Escondida, TrelewZulima América Schupbach
5059906/01/2013ArgentinaChubutTrelewNicolas Chimento
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 11/03/2026.