Ayres's Hawk-eagle Hieraaetus ayresii


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. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2021 Least Concern
2016 Least Concern
2012 Least Concern
2009 Least Concern
2008 Least Concern
2004 Least Concern
2000 Lower Risk/Least Concern
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency Medium
Land mass type Average mass -

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 16,400,000
Extent of Occurrence non-breeding (km2) 19,000,000
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 20000-49999 poor estimated 2021
Population trend Decreasing suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 10-20 - - -
Decline (10 years/3 generation past and future) 10-20 - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 7.8 - - -

Population justification: According to the current range map, the area of this species’s resident range is 5,850,542 km2. Based on a possible population density of 1 pair/50 km2 (J. Bradly in litt. 2021), and given that only a small portion of its range is likely to be occupied (assumed here at 10-20%), the population may number 23,402 – 46,804 mature individuals. In the absence of other data, the population is therefore placed in the band 20,000 – 49,999 mature individuals.

Trend justification: During the years 2001-2019, 8.5% of forest cover was lost across this species's range (Global Forest Watch 2021), equating to a loss of 10% over three generations (23.4 years [Bird et al. 2021]). During the years 2016-2019, 3% of forest cover was lost (Global Forest Watch 2021), equivalent to 16% when projected forward over three generations. However, this species prefers smaller woodland fragments and is absent from large areas of dense forest (J. Bradley in litt. 2021). It can also utilise plantations, as well as savannas and urban areas, therefore it is assumed to decline at a slower rate that forest loss alone. It may also be increasing in Kenya (S. Hatfield, S. Kapila, S. Thomsett, C. Jackson, G. Vande weghe, Z. Cockar, S. Shema and D. Ogada in litt. 2021), and in urban areas it may have benefited from the increase in mature stands of exotic trees and the availability of feral pigeons as prey (W. Goodwin in litt. 2021). 

The species is subjected to direct persecution in the south of their non-breeding range (Kemp and Boesman 2013). While the rates of persecution are unknown, this is a small part of the range, and therefore the overall rate of decline is suspected to be <20% over three generations.

Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Angola N Extant Yes
Benin N Extant Yes
Botswana N Extant Yes
Cameroon N Extant Yes
Chad N Extant Yes
Congo N Extant Yes
Congo, The Democratic Republic of the N Extant Yes
Côte d'Ivoire N Extant Yes
Ethiopia N Extant Yes
Gabon N Extant Yes
Ghana N Extant Yes
Guinea N Extant Yes
Guinea-Bissau V Extant
Kenya N Extant Yes
Liberia N Extant Yes
Malawi N Extant Yes
Mozambique N Extant Yes
Nigeria N Extant Yes Yes
Rwanda N Extant Yes
Senegal V Extant
Sierra Leone N Extant Yes
Somalia V Extant
South Africa N Extant Yes
South Sudan V Extant Yes
Sudan V Extant
Tanzania N Extant Yes
Uganda N Extant Yes
Zambia N Extant Yes
Zimbabwe N Extant Yes Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Kenya Mumoni Hill Forest Reserve

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Plantations suitable non-breeding
Artificial/Terrestrial Urban Areas suitable non-breeding
Forest Subtropical/Tropical Dry suitable resident
Forest Subtropical/Tropical Moist Lowland suitable resident
Forest Subtropical/Tropical Moist Montane suitable resident
Forest Temperate suitable resident
Savanna Dry suitable resident
Altitude 0 - 3000 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Biological resource use Hunting & trapping terrestrial animals - Persecution/control Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Species mortality
Biological resource use Logging & wood harvesting - Motivation Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion
Pollution Agricultural & forestry effluents - Herbicides and pesticides Timing Scope Severity Impact
Ongoing Majority (50-90%) Unknown Unknown
Species mortality

Purpose Primary form used Life stage used Source Scale Level Timing
Pets/display animals, horticulture - - International Non-trivial Recent

Recommended citation
BirdLife International (2022) Species factsheet: Hieraaetus ayresii. Downloaded from on 19/01/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from on 19/01/2022.