Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Accipitriformes Accipitridae

Scientific Name: Geranoaetus polyosoma
Species Authority: (Quoy & Gaimard, 1824)
Common Name(s):
English Variable Hawk, Variable Hawk
Buteo poecilochrous Gurney, 1879
Buteo polyosoma (Quoy & Gaimard, 1824)
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Taxonomic Notes: Geranoaetus polyosoma (del Hoyo and Collar 2014) was previously placed in the genus Buteo. Buteo poecilochrous (Sibley and Monroe 1990, 1993; Stotz et al. 1996) was also lumped with B. polyosoma following SACC (2006).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Symes, A.
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Previously published Red List assessments:
2009 Least Concern (LC)
2008 Not Recognized (NR)
2004 Not Recognized (NR)
2000 Not Recognized (NR)
1994 Not Recognized (NR)
1988 Not Recognized (NR)

Geographic Range [top]

Countries occurrence:
Argentina; Bolivia, Plurinational States of; Chile; Colombia; Ecuador; Falkland Islands (Malvinas); Paraguay; Peru; Uruguay
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 3160000
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Lower elevation limit (metres): 500
Upper elevation limit (metres): 5000
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The global population size has not been quantified, but this species is described as 'fairly common' (Stotz et al. (1996).

Trend Justification:  The population is suspected to be decreasing locally in Ecuador, Chile and Argentina (Ferguson-Lees and Christie 2001).
Current Population Trend: Increasing
Additional data:
Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Citation: BirdLife International. 2012. Geranoaetus polyosoma. The IUCN Red List of Threatened Species 2012: e.T22735520A39071467. . Downloaded on 08 October 2015.
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