Species

Justification
This species is suspected to be undergoing a rapid population decline owing to the widespread and on-going loss of lowland forest, which qualifies it as Vulnerable.

Taxonomic source(s)
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Taxonomic note
Spizaetus nanus, S. lanceolatus, S. philippensis, S. pinskeri, S. nipalensis, S. alboniger and S. bartelsi (Sibley and Monroe 1990, 1993) and S. cirrhatus and S. floris (Gjershaug et al. 2004) have been transferred into the genus Nisaetus following Haring et al. (2006). S. africanus and Hieraaetus fasciatus (Sibley and Monroe 1990, 1993) have both been transferred into Aquila, also following Haring et al. (2006); and H. kienerii (Sibley and Monroe 1990, 1993) has been transferred into the resurrected genus Lophotriorchis. The BirdLife Taxonomic Working Group is aware that phylogenetic analyses have been published which have proposed moving H. pennatus into Aquila but as not all published studies are concordant we prefer not to take a decision on this until cladogenesis of the 'booted eagles' has been resolved.

Identification
46 cm. Small, boldly-patterned hawk-eagle. Rufescent sides of head with blackish streaks, dark crest broadly tipped white, three dark bands on tail. Buffish-white base-colour to underside flight feathers and warm buffish coverts with narrow dark barring. Similar spp. Blyth's Hawk-eagle S. alboniger is larger, has narowly white-tipped crest, blackish tail with pale grey broad, central band and narrow tip. Whitish underwing with heavy black barring on coverts and dark sides of head. Voice Shrill, high-pitched yik-yee or kliit-kleeik, with rising second note. Fledged juveniles give high-pitched, breathless yii-yii-yii-yii and ee-ee-ee-ee-eeee.

Distribution and population
Spizaetus nanus occurs in southern Tenasserim, Myanmar, peninsular Thailand, Peninsular and East (Sabah and Sarawak) Malaysia, Brunei, and Kalimantan and Sumatra, Indonesia (BirdLife International 2001). Although still widespread, it is uncommon or rare throughout its range. It may be nearing extinction in Thailand and is declining everywhere. However, its status is somewhat unclear because of the difficulties of separating it from S. alboniger.

Population justification
The population size is preliminarily estimated to fall into the band 2,500-9,999 mature individuals. This equates to 3,750-14,999 individuals in total, rounded here to 3,500-15,000 individuals.

Trend justification
The species has suffered as a result of extensive forest loss owing to logging, conversion to plantations and agriculture, and major forest fires. As a result it is suspected to have declined rapidly.

Ecology
It is resident in evergreen forests, chiefly in the lowlands and on lower hill-slopes, but has occasionally been reported up to 1,000 m. It may tolerate some habitat degradation, having been recorded in heavily logged forest in Kalimantan and Sumatra, and logged forest in Malaysia. However, a study in Malaysia recorded it in primary forest prior to selective logging, but not subsequently.

Threats
The key threats are habitat loss, degradation and fragmentation as a result of large-scale commercial logging, including within protected areas, and widespread forest clearance for plantation agriculture (primarily rubber and oil-palms). Between 1985-1997, nine million and nearly seven million hectares of forest were lost on Kalimantan and Sumatra, respectively. The impact of the major fires of 1997-1998 has yet to be fully assessed, but fires appear to be increasing in frequency and severity on Sumatra and Borneo. In Thailand, virtually all lowland forest has now been cleared, and encroachment continues on the lower slopes of almost all mountains. Despite these negative statistics, the species has shown resilience to at least a degree of habitat modification, even recorded within small lowland forest patches within oil palm plantations in Sabah (Yeap Chin Aik in litt. 2007).

Conservation actions underway
CITES Appendix II. It occurs in numerous protected areas, including at least six (four national parks and two wildlife reserves) on Sumatra, at least three (two national parks and one wildlife reserve) in Kalimantan, at least five (one national park and four wildlife sanctuaries) in Thailand, at least three (two national parks and one wildlife reserve) in Malaysia, and one wildlife sanctuary in Myanmar.

Conservation actions proposed
Conduct extensive surveys to more clearly establish its distribution and status compared with S. alboniger. Conduct research into its ecological requirements, particularly its tolerance of habitat degradation and its ranging behaviour. Promote the concept of Forest Management Units in Sabah. Assist forest managers in habitat identification and zoning of concession areas. Afford it full legal protection under Myanmar, Thai, Indonesian and Malaysian law.

References
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).

Hear sounds for this species from xeno-canto, the community database of shared bird sounds from around the world.

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

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

Contributors
Aik, Y., Davison, G., Iqbal, M.

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

Recommended citation
BirdLife International (2013) Species factsheet: Nisaetus nanus. Downloaded from http://www.birdlife.org on 25/05/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/05/2013.

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.

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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

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