Apo Sunbird Aethopyga boltoni


Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and 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
2020 Least Concern
2016 Near Threatened B1ab(iii)
2012 Near Threatened B1ab(iii)
2008 Near Threatened B1a+b(iii)
2004 Near Threatened
2000 Lower Risk/Near Threatened
1994 Lower Risk/Near Threatened
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency medium
Land-mass type shelf island
Average mass 6 g

Estimate Data quality
Extent of Occurrence (breeding/resident) 31,600 km2 medium
Severely fragmented? no -
Estimate Data quality Derivation Year of estimate
Population size 15000-24999 mature individuals poor suspected 2020
Population trend stable - suspected -
Generation length 2.4 years - - -

Population justification: The species is described as fairly common within its small range (Cheke et al. 2001). Assuming that it occurs at similar densities to a congener, Lovely Sunbird (Aethopyga shelleyi), at 49.1 individuals/km2 (Santini et al. 2018), with 10% of the mapped range likely occupied, the population may thus number 37,000 individuals, roughly equating to 25,000 mature individuals. However, the species is thought to occur at lower densities than congeners across its suitable habitat (P. Simpson in litt. 2020). Assuming that this value is a maximum therefore, the population is tentatively placed in the band of 15,000-24,999 mature individuals.

Trend justification: Forests within the range of the species are not thought to be under imminent threat. Recent fores loss estimates remain low at <5% (Tracewski et al. 2016, Global Forest Watch 2020) over a 3-generation period (10 years; Bird et al. 2020). The population is therefore suspected to be stable in the absence of evidence for any substantial declines or threats.

Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Philippines extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Philippines Mount Agtuuganon and Mount Pasian
Philippines Mount Kitanglad
Philippines Mount Apo
Philippines Mount Busa-Kiamba
Philippines Mount Malindang

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Montane major resident
Shrubland Subtropical/Tropical High Altitude suitable resident
Altitude 1500 - 0 m Occasional altitudinal limits 823 - 2000 m

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2024) Species factsheet: Aethopyga boltoni. Downloaded from on 21/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from on 21/02/2024.