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Ryukyu Serpent Eagle
Spilornis perplexus

Status: Vulnerable

Population Trend: Stable.

Other Names: Ryukyu Crested Serpent-eagle, Ryukyu Serpent-eagle.

Spilornis perplexus
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Distribution: Indomalayan. Endemic to Nansei-shoto Islands (formerly RYUKYU ISLANDS (Ishigaki-shima and Iriomote; accidental on Yonaguni) of JAPAN.

Subspecies: Monotypic.

Taxonomy: This form was regarded as a race of S. cheela by Stresemann and Amadon (1979) and del Hoyo et al. (1994), but it was treated as a separate species by Ferguson-Lees and Christie (2001) on the basis of differences in color and size between it and S. cheela hoya on Taiwan, the nearest congeneric population.

Movements: Probably non-migratory.

Habitat and Habits: Occurs in subtropical evergreen forest below 500 m and in coastal lowlands and farmlands (Brazil 2009). Often seen soraing and on open perches on trees and poles.

Food and Feeding Behavior: Feeds on snakes, frogs, and other small prey (Ferguson-Lees and Christie (2001). Its hunting strategy is probably like that of other Spilornis species, i.e., mostly still-hunting from a concealed or exposed perch, often by a stream or a clearing.

Breeding: No information.

Conservation: Probably at some threat from habitat loss. Most organizations considered this taxon to be a subspecies of the widespread S. cheela, so do not categorize its status separately. Here it is given species status (in agreement with Ferguson-Lees & Christie, 2001) in order to bring attention to its vulnerable status.

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 101 to 1,000 birds, based on surveys in the 1980s, which yielded a population estimate then of just under 100 birds on Ishigaki-shima and Iriomote-shima.

Important References: 
Brazil, M. 2009. Birds of East Asia: China, Taiwan, Korea, Japan, and
  Russia. Princeton University Press, Princeton, NJ.
Clark, W.S. 1994. Crested Serpent-eagle. P. 133 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.
Chikara, O. 2002. Little-known and neglected distinctive (sub) species of
  southern Japan. Oriental Bird Club Bulletin 35:26-32.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Harato, T. 1987. [Food habits and behavior of a fledgling of the Crested
  Serpent-eagle, Spilornis cheela perplexus, in Iriomote-jima
  Island, Okinawa]. Island Studies in Okinawa 5:49-59. (In Japanese)
Kinjyo, T., and K. Miyagi. 2006. (Abstract) The state of Crested Serpent
  Eagle inhabit in Japan, in Abstracts of the 3rd Symposium on Ecology of
  Raptors in Taiwan, Taipei, Taiwan. Raptor Research of Taiwan 6:45-46.
Sano, K. 2003. [Breeding biology of the Ryukyu Crested Serpent Eagle in
  Ishigaki Island, Okinawa]. Strix 21:141-150. (In Japanese)
Ueta, M., and J.S. Minton. 1996. Habitat preference of Crested
  Serpent-eagles in southern Japan. Journal of Raptor Research

Last modified: 8/3/2015

Recommended Citation: Global Raptor Information Network. 2020. Species account: Ryukyu Serpent Eagle Spilornis perplexus. Downloaded from http://www.globalraptors.org on 26 May. 2020

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