Kinabalu Serpent-eagle Spilornis kinabaluensis


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
2022 Near Threatened C2a(ii)
2016 Vulnerable C2a(ii)
2012 Vulnerable C2a(ii)
2008 Vulnerable C2a(ii)
2004 Vulnerable
2000 Vulnerable
1996 Data Deficient
1994 Data Deficient
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Land-mass type - shelf island
Average mass -

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 314,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 2500-19999,5000-9999 poor inferred 2020
Population trend Decreasing poor 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) 5-15 - - -
Decline (10 years/3 generation past and future) 5-15 - - -
Number of subpopulations 1 - - -
Percentage in largest subpopulation 100 - - -
Generation length (yrs) 8.1 - - -

Population justification: The area mapped (which accounts for suitable habitat and altitude) for this species encompasses c.156,000 km2. No density estimates of this species have been recorded, but Ferguson-Lees and Christie (2001) suggested a density of one pair/100 km2 (accounting for density and occupancy) recorded for S. cheela was appropriate to generate a global population estimate for the latter, equivalent here to c.3,120 mature individuals if applied to S. kinabaluensis. However, Ferguson-Lees and Christie (2001) also acknowledged that home ranges of S. cheela as small as 5-6 km2 had been recorded in optimum habitat. Applying this density to the range of S. kinabaluensis with a 30% occupancy gives a much greater value of 18,720 mature individuals. For these reasons, the population is suspected to comprise 2,500-19,999 mature individuals, with a most likely figure of 5,000-9,999 mature individuals. However, there is substantial uncertainty in this figure and acquiring species-specific density estimates should be considered a research priority. More qualitatively, the species is described as scarce in Sabah, but fairly common in Sarawak and Kalimantan (Eaton et al. 2021).

Trend justification: A population decline is suspected because of ongoing forest loss in its range. This species is highly forest dependent and is suspected to be declining at the same rate as forest loss; rates of forest cover loss have averaged c.9-11% over the last three generations [24 years; Bird et al. 2020] (Global Forest Watch [2021], using Hansen et al. [2013] data and methods disclosed therein) and this rate is suspected to continue into the future, although may in time begin to slow as higher altitude forest is less accessible.

Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Brunei N Extant Yes
Indonesia N Extant Yes
Malaysia N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Brunei Ulu Temburong
Malaysia Trus Madi Range
Malaysia Crocker Range
Malaysia Mulu - Buda Protected Area
Malaysia Mount Kinabalu
Malaysia Dulit Range
Malaysia Kelabit Highlands

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Montane major resident
Altitude 1100 - 2900 m Occasional altitudinal limits (min) 750 m

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Unknown Unknown Unknown Unknown
Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation

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

Recommended citation
BirdLife International (2023) Species factsheet: Spilornis kinabaluensis. Downloaded from http://www.birdlife.org on 02/04/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/04/2023.