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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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 Detail of places sorted by number of records








Page 1
Record IDDateExact timeCountryProvince / departmentPlaceFilmedPhotographedRecorded vocalObservedHeardWounded or deadNumber of individualsUser or BibliographyDetail
217348227/08/2024ArgentinaSaltaLagunas Del Toro, Rosario de Lerma2Ralph Roberts
217342527/08/2024ArgentinaSaltaEmbalse Laguna del Toro, Rosario de Lerma1Ralph Roberts
206845508/02/2024ArgentinaChubutLagunas de Nahuelpan, Futaleufú1Ralph Roberts
206845407/02/2024ArgentinaChubutLaguna Willmanco, Futaleufú2Ralph Roberts
206845706/02/2024ArgentinaChubutTrevelin--Laguna Brychan, Futaleufú1Ralph Roberts
206845605/02/2024ArgentinaChubutMalacara, Futaleufú3Ralph Roberts
206846004/02/2023ArgentinaChubutRuta Nacional 25, Paso de Indios1Ralph Roberts
206845320/01/2023ArgentinaChubutEsquel--RNU Laguna La Zeta, Futaleufú1Ralph Roberts
206845818/01/2023ArgentinaSanta CruzVía sin nombre, Lago Buenos Aires1Ralph Roberts
206845918/01/2023ArgentinaChubut1670 Ruta Nacional 40, Languiñeo1Ralph Roberts
Page 1

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Citation recommended:

EcoRegistros. 2026. Variable Hawk (Geranoaetus polyosoma) - Species sheet. Acceded from https://www.ecoregistros.org on 19/03/2026.