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Kinabalu Serpent-eagle Spilornis kinabaluensis
BirdLife is updating this factsheet for the 2016 Red List
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Given the small range and relative mobility of this species, it is judged to comprise a single small population which is likely to be decreasing as a result of continuing habitat loss and degradation creeping up hill-slopes into its altitudinal range. For these reasons it qualifies as Vulnerable.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.

51-56 cm. Small, dark, forest-dwelling eagle. Plumage dark brown, speckled paler on underparts, wings and hindneck. Rich umber-brown patch on nape. Black throat. Fairly long, blackish tail with broad white band. Long wings with black tips and white bases to flight feathers. Similar spp. Its widespread relative, Crested Serpent-eagle S. cheela, is paler with shorter wings and narrower, less distinct greyish-white band on tail. Hints Frequently soars over ridge-tops and occurs at higher altitudes than S. cheela. Voice High repeated whistling notes similar to S. cheela.

Distribution and population
Spizaetus kinabaluensis is confined to the mountains of central and northern Borneo in Brunei, Sabah and Sarawak, Malaysia, and Kalimantan, Indonesia (BirdLife International 2001). From observations in the 1980s and 1990s, it appears to be a genuinely scarce species, with a small total population. However, much of its range is infrequently visited and it may prove to be more widespread than current indications suggest. It is likely to occur more or less continuously along the Crocker Range from Mount Kinabalu to Ulu Padas, G. Mulu and the border mountains of Brunei, and Gunung Murud (Pulong Tau National Park) (G. Davison in litt. 2007). The southern and western limits of its distribution are poorly known and need to be investigated, e.g., its occurrence in the Kelabit Highlands and Usun Apau, Kayan Mentarang and central montane parts of Kalimantan (G. Davison in litt. 2007).

Population justification
The population is estimated to number 2,500-9,999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.

Trend justification
A population decline is suspected on the basis of rates of logging and land clearance from lower altitudes up into the montane habitat of this species. The likely rate of population decline, however, has not been estimated.

It is apparently sedentary in submontane and montane evergreen rainforest where it tends to prefer ridge-top forest at 750-2,900 m. In areas where it occurs alongside S. cheela it is separated vertically by a few hundred metres.

Habitat loss, degradation and fragmentation are the primary threats to the species, particularly towards the lower altitudinal limits of its distribution, where the extent of forest is diminishing fairly rapidly in the face of agricultural expansion and intensification, although forest at higher altitudes is also threatened, for example by small-holder agriculture (G. Davison in litt. 2007, 2012).

Conservation Actions Underway
CITES Appendix II. It occurs within Kinabalu and Mulu National Parks and Temburong/Kuala Belalong (Brunei) (G. Davison in litt. 2007).
Conservation Actions Proposed
Conduct fieldwork to determine the range (particularly the southern and western limits) and population size of this species along with the degree of threat it faces from habitat destruction. Propose further sites for establishment as protected areas in the Bornean highlands. Ensure effective management of key protected areas for the species, including lending support to the 'Heart of Borneo' initiative.

BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

Explore HBW Alive for further information on this species

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Bird, J., Davidson, P., Taylor, J., Tobias, J.

Davison, G., Mann, C., van Balen, B.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Spilornis kinabaluensis. Downloaded from on 23/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 23/10/2016.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Mountain serpent eagle (Spilornis kinabaluensis) 0

Key facts
Current IUCN Red List category Vulnerable
Family Accipitridae (Hawks, Eagles)
Species name author Sclater, 1919
Population size 2500-9999 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 36,700 km2
Country endemic? No
Links to further information
- Additional Information on this species