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Blyth's Hawk-eagle
Nisaetus alboniger

Status: Lower risk

Population Trend: Unknown.

Other Names: Blyth's Hawk Eagle, Spizaetus alboniger.

Nisaetus alboniger
click to enlarge
Distribution: Indomalayan. Southern MYANMAR and southern THAILAND through Malay Peninsula to SUMATRA and associated islands; northern BORNEO. more....

Subspecies: Monotypic.

Taxonomy: Traditionally placed in the genus Spizaetus, but recent molecular studies by Helbig et al. (2005) showed that the Asian hawk-eagle species represent a different lineage from the New World hawk-eagle species and should therefore be assigned to a new genus for which the name Nisaetus Hodgson 1836 is available. The same conclusion was reached independently by Lerner and Mindell (2005), who also found that N. alboniger and N. nipalensis are sister species, based on the molecular sequences of two mitochondrial genes and one nuclear entron. Haring et al. (2007) also confirmed that Asian Spizaetus (Nisaetus) species are monophyletic and are distributed in two sub-clades, one of which consists of N. alboniger, N. bartelsi, N. nanus, and N. nipalensis.

Movements: Non-migratory, but juveniles disperse from breeding areas (Bildstein 2006).

Habitat and Habits: In Malaysia, it occurs in the interior and edge of lowland and montane forest, mature and selectively logged, typically in steep country from the hill-foot boundary to at least 1,800 m (Wells 1999). Nests recorded in the Main Range have been within about 400 m below the montane ecotone to only just above it (Robinson and Seywald 1987), apparently limited upward by the availability of emergent trees for nesting. Wanders widely in the lowlands of Malaysia. Soars often over the forest canopy.

Food and Feeding Behavior: The diet is poorly known, but there are records of birds taking lizards and a bat. It still hunts from shaded perches insude and at the edge of forest, at interior canopy down to mid-levels, sometimes only a few meters above a quiet forest road (Wells 1999). more....

Breeding: The nest is a thick platform of sticks with a cup deep enough to conceal the body of the sitting parent when viewed at eye-level and placed in a main branch fork of a large emergent tree, often above the level of the surrounding canopy (Wells 1999). The birds continue to add leafy branches to the lining within a few days of the chick fledgling. Clutch size may be one egg, since all reported broods have been of a single chick (Wells 1999). The egg is apparently undescribed, and neither the incubation nor nestling periods are known. However, the total development period is no longer than four months, since a bird incubating in mid-November had a small, downy chick in December, which fledged on 17 February (Wells op cit.). more....

Conservation: Although this species has been regarded as fairly common in at least some parts of its range, its populations are probably in decline as a result of ongoing deforestation and conversion of habitats for agriculture. Categorized as a species of "Least Concern" by BirdLife International. more....

Population Estimates: Ferguson-Lees and Christie (2001) placed the global population (defined as the number of adults and immatures at the start of the breeding season) in the range of 1,001 to 10,000 individuals. BirdLife International (2009) estimated the total number of mature birds at 1,000 individuals.

Important References: 
Amadon, D. 1953. Remarks on the Asiatic hawk-eagles of the genus
  Spizaetus. Ibis 95:492-500.
Clark, W.S. 1994. Blyth's Hawk-eagle. P. 203 in del Hoyo, J., A. Elliott,
  and J. Sargatal (eds). Handbook of birds of the world. Vol. 2. New World
  vultures to guineafowl. Lynx Edicions, Barcelona, Spain.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Gjershaug, J.O.. 2006. Taxonomy and conservation status of hawk-eagles
  (Genus Nisaetus) in South-east Asia. Ph.D. dissertation, Norwegian
  University of Science and Technology, Trondheim, Norway.
Haring, E., K. Kvaløy, J.O. Gjershaug, and A. Gamauf. 2007. Convergent
  evolution and paraphyly of the hawk-eagles of the genus Spizaetus (Aves,
  Accipitridae) -- phylogenetic analyses based on mitochondrial markers.
  Journal of Zoological Systematics and Evolutionary Research 45:353-365.
Helbig, A.J., A. Kocum, I. Seibold, and M.J. Braun. 2005. A multi-gene
  phylogeny of aquiline eagles (Aves: Accipitriformes) reveals extensive
  paraphyly at the genus level. Molecular Phylogenetics and Evolution
Lerner, H.R., and D.P. Mindell. 2005. Phylogeny of eagles, Old World
  vultures, and other Accipitridae based on nuclear and mitochondrial DNA.
  Molecular Phylogenetics and Evolution 37:327-346.
Stresemann, E. 1938. Spizaetus alboniger (Blyth) und Spizaetus nanus
  Wallace, zwei fälschlich vereinigte Arten. Journal für Ornithologie
van Balen, B.S. 1998. Tropical forest raptors in Indonesia: recent
  information on distribution, status, and conservation. Journal of Raptor
  Research 32:56-63.
Wells, D.R. 1999. The birds of the Thai-Malay Peninsula. Volume 1.
  Non-passerines. Academic Press, London.

Sites of Interest:
Blyth's Hawk-eagle photos.
ARRCN Spizaetus Distribution Maps
Aims to create distribution maps and habitat analysis for the genus Spizaetus (Nisaetus) in Asia.

Gamauf, Anita
Gjershaug, Jan Ove
Kim Chye, Lim
Lim, Aun -Tiah
Purba, Dertina

Last modified: 9/16/2009

Recommended Citation: Global Raptor Information Network. 2022. Species account: Blyth's Hawk-eagle Nisaetus alboniger. Downloaded from http://www.globalraptors.org on 23 Jan. 2022

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