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Madagascar Serpent Eagle
Eutriorchis astur

Status: Endangered

Population Trend: Declining.

Other Names: Long-tailed Serpent-eagle, Madagascar Forest Eagle, Madagascar Serpent-eagle.

Eutriorchis astur
click to enlarge
Distribution: Afrotropical. Endemic to eastern MADAGASCAR. more....

Subspecies: Monotypic.

Taxonomy: Brown and Amadon (1968) suggested that this species and the Congo Serpent Eagle (Dryotriochis spectabilis) might be congeneric and that the Madagascar Serpent Eagle might be related to the serpent eagles, Spilornis. In contrast, the study of Lerner and Mindell (2005), which was based on the molecular sequences of two mitochondrial genes and one nuclear intron, clearly show that the Madagascar Serpent Eagle is a member of the subfamily, Gypaetinae, where it clusters with the Palm-nut Vulture (Gypohierax angolensis), Egyptian Vulture (Neophron percnopterus), and the Bearded Vulture (Gypaetus barbatus). Each is highly divergent from each other genetically, but they are still more closely related to each other than to other accipitrine species.

Movements: Non-migratory (Bildstein 2006).

Habitat and Habits: Occurs in primary rainforest and forest edges up to 1,000 m, (Thorstrom et al. 2003), spending most its time perched motionless below the canopy. They rarely fly or soar above the canopy and are generally very elusive and secretive. Their presence is best detected by their distinctive frog-like call, which is given in the early morning and occasionally in late afternoon prior to roosting (Thorstrom et al. 2003). more....

Food and Feeding Behavior: Feeds mostly on lizards, including chameleons (Furcifer and Calumna spp.) and Leaf-tailed Geckos (Uroplatus spp.), plus tree frogs (Thorstrom and René de Roland 2000), and, less commonly, on snakes, bats, and insects (Thorstrom et al. 2003). Reports by local residents of it feeding on small mammals and chickens are doubtful and probably result from confusion with Henst's Goshawk Accipiter henstii. This species hunts from the ground up to the subcanopy, where it usually perches for several minutes, scanning up and down and from side to side, before flying to another nearby perch and resuming the scanning process (Thorstrom et al. 2003). more....

Breeding: Only two nesting attempts have been well documented, although five nesting attempts have been records in the Makira forest (Thorstrom et al. 2003, Thorstrom pers. comm.). Both of the nests that were studied were made of sticks and were well hidden in epiphytic ferns within the dense canopy of primary raiforest. The clutch size was a single, unmarked white egg. Both adults incubated, with the female doing the majority (78%), and the female also attended the single nestling; both parents delivered fresh twigs with leaves to the nest (Thorstrom and René de Roland 2000). The incubation period was about 40 days at one nest, and the recorded nestling periods were 58 and 62 days (Thorstrom et al. 2003). The male delivered 75% of the prey items, and the female did not begin hunting and delivering prey until the chick was 18 days old. Both parents continued delivering prey items to a chick after it fledged, but it began hunting on its own within 10 days after fledging. more....

Conservation: Until fairly recently, this species was known from only 11 specimens, with the last one taken in 1935 (Dee 1986). In later years, there were only a few sight reports of the species until 1993, when a bird was captured and photographed on the Masoala Peninsula by a Peregrine Fund field team (Thorstrom et al. 1995). Subsequently, studies by Russell Thorstrom, Lily René de Roland, Steve Goodman, and other researchers have shown that the Madagascar Serpent Eagle is more common than formerly believed and not in imminent danger of extinction, as previously thought. Nevertheless, it occupies only a limited range within the forests of northeastern Madagascar, where it is extremely vulnerable to any loss of primary forests. Categorized globally as Endangered by BirdLife International (2009). more....

Population Estimates: The total global population probably numbers in the low hundreds. Thorstrom and René de Roland (2000) estimated that as many as 104 territorial pairs may exist in the Masoala National Park and other portions of the peninsula, if the habitat is saturated. BirdLife International places the number of mature birds in the range of 250-999 individuals.

Important References: 

Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Kemp, A.C. 1994. Madagascar Serpent-eagle. P. 134 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.
Rand, A.L. 1936. The distribution and habits of Madagascar birds. Bulletin
  of the American Museum of Natural History 72:143-499.
Raxworthy, C.J., and P.R. Colston. 1992. Conclusive evidence for the
  continuing existence of the Madagascar Serpent-eagle Eutriorchis astur.
  Bulletin of the British Ornithologists' Club 112:108-111.
Sheldon, B.C., and J.W. Duckworth. 1990. Rediscovery of the Madagascar
  Serpent-eagle Eutriorchis astur. Bulletin of the British
  Ornithologists' Club 110:126-130.
Thorstrom, R., and L.-A. René de Roland. 1997. Madagascar Serpent-eagle:
  current status on Masoala Peninsula. Pp. 143-147 in R.T. Watson (ed.),
  Masoala Project: use of raptors and other avifauna for conservation,
  monitoring and evaluation of rain forest on Masoala Peninsula. The Peregrine
  Fund, Boise, ID.
Thorstrom, R., and L.-A. René de Roland. 2000. First nest description,
  breeding behaviour and distribution of the Madagascar Serpent-eagle
  Eutriorchis astur. Ibis 142:217-224.
Thorstrom, R., and L.-A. René de Roland. 2000. Status and conservation of
  raptors on the Masoala Peninsula, Madagascar. Pp. 35-41 in R.D. Chancellor
  and B.-U. Meyburg (eds.), Raptors at risk. World Working Group on Birds of
  Prey, Berlin and Hancock House, Blaine, WA.
Thorstrom, R., and L.-A. René de Roland. 2003. Eutriorchis astur,
  Madagascar Serpent-eagle, Fancrasalambo. Pp. 1088-1091 in S.M. Goodman
and J.P. Benstead (eds.), The natural history of Madagascar.
  Universitry of Chicago Press, Chicago, IL.
Thorstrom, R., R.T. Watson, B. Damary, E. Toto, M. Baba, and V. Baba.
  1995. Repeated sightings and first capture of a live Madagascar
  Serpent-eagle Eutriorchis astur. Bulletin of the British
  Ornithologists' Club 115:40-45. more....

Sites of Interest:
The Peregrine Fund
Long-term field studies under the direction of Russell Thorstrom.

Rene de Roland, Lily-Arison
Thorstrom, Russell

Last modified: 10/23/2011

Recommended Citation: Global Raptor Information Network. 2020. Species account: Madagascar Serpent Eagle Eutriorchis astur. Downloaded from http://www.globalraptors.org on 6 Jul. 2020

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