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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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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: 665767
 
Camino sin nombrar
Río Negro
Argentina
01/01/2026
Mariano Costa
Foto
Photography ID: 245781
  Adult

Frutillar
Región de Los Lagos
Chile
01/27/2018
Mariano Costa
Foto
Photography ID: 241811
  Juvenile

Parque Nacional Nahuel Huapi
Río Negro
Argentina
01/21/2018
Mariano Costa
Foto
Photography ID: 122664
  Juvenile

Área Natural Protegida Punta Tombo
Chubut
Argentina
10/04/2015
Mariano Costa
Foto
Photography ID: 41890
  Juvenile

Puerto Madryn
Chubut
Argentina
03/01/2014
Mariano Costa
Foto
Photography ID: 41889
  Adult

Parque Nacional Nahuel Huapi
Río Negro
Argentina
03/04/2014
Mariano Costa



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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
242263726/01/202615:41ArgentinaRío NegroCamino sin nombrarMariano Costa
241822818/01/202615:47ArgentinaRío NegroCamino sin nombrarMariano Costa
241819616/01/202612:05ArgentinaRío NegroCamino sin nombrarMariano Costa
240870101/01/202618:01ArgentinaRío NegroCamino sin nombrarMariano Costa
240286520/12/2025ArgentinaRío NegroRp1 / R40s Entrada a Ñorquinco, Ñorquinco1Mariano Costa
238083530/10/202516:15ArgentinaRío NegroRuta Nacional 23Mariano Costa
235691811/09/202517:10ChileRegión de Los LagosCostanera Pedro Montt 89, QuellónMariano Costa
214752010/09/2024ArgentinaRío NegroRuta Nacional 231Mariano Costa
210188007/07/2024ArgentinaRío NegroRuta Nacional 151Mariano Costa
194696014/01/2024ArgentinaRío NegroSan Carlos de Bariloche1Mariano Costa
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 29/03/2026.