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Madagascar Harrier-hawk
Polyboroides radiatus

Status: Lower risk

Population Trend: Stable.

Other Names: Banded Gymnogene, Madagascar Gymnogene, Madagascar Harrier Hawk.


Polyboroides radiatus
click to enlarge
Distribution: Afrotropical. Endemic to MADAGASCAR. more....

Subspecies: Monotypic.

Taxonomy: Forms a superspecies with P. typus, but possibly a race of that species (Amadon and Bull 1988). If so, the combined species would be called P. radiatus, the name with priority. Various authorities have commented on the similarity in morphology and feeding habits between this genus and the Crane Hawk, Geranospiza caerulesens, of tropical America, and Friedmann (1950) hypothesized that they are closely related. However, subsequent authors (e.g., Burton 1978) concluded that their morphological similarities were due to convergent evolution. The study of Lerner and Mindell (2005), based on molecular sequences from two mitochondrial genes and one nuclear intron, confirmed that Geranospiza is not closely related to Polyboroides.

Movements: Probably non-migratory.

Habitat and Habits: Found in in a wiude variety of habitats, ranging from montane rainforest to spiny desert scrub, from primary to degraded forests to wooded habitat, including exotic tree plantations (Karpanty and Goodman 1999, Thorstrom et al. 2003). Frequently seen soaring above the forest canopy. more....

Food and Feeding Behavior: Has a diverse diet, including small lemurs, flying foxes, birds and contents of bird nests, reptiles, amphibians, and insects (Rand 1936, Karpanty and Goodman 1999). Like its mainland congener, P. typus, this species climbs around tree trunks and limbs, balancing itself with flapping wings as it peers into holes and reaches into crevices of trees with its long legs in search of small animal prey. It also hunts on the wing, soaring slowly between trees, before descending to take prey from trees or the ground, and it sometimes searches for food by walking on the ground. more....

Breeding: Builds a stick nest placed in the main fork of a large tree. Four nesting attempts were recorded during a 1992 raptor survey on the west coast of the Masoala Peninsula. One pair nested at the same site from 1991-1997, invariably laying two eggs, but fledging only a single young in 1994 and 1996 as a result of siblicidal behavior (Thorstrom and René de Roland 2000, Thorstrom and La Marca 2000). Langrand (1990) and Thorstom and La Marca (2000) also reported a clutch size of two eggs, which are white with brownish spots. The incubation period is 39 days, and the nestling period is 50 days (Thorstrom and La Marca op cit.). more....

Conservation: Fairly common in the eastern and northeastern forested portions of Madagascar, where it is vulnerable to deforestation. Thorstrom and René de Roland (2000) reported an instance of villagers trapping, killing, and eating a harrier-hawk because it preyed upon their chickens. Categorized globally as a species of "Least Concern" by BirdLife International.

Important References: 
Borge, L. 1992. First studies on Madagascar Harrier-hawk and Henst's
  Goshawk. Pp. 73-74 in R.T. Watson (ed.), Project report I, 1991 and 1992.
  Madagascar Project: an integrated program for development of local capacity
  for conservation of natural resources. The Peregrine Fund, Boise, ID.
Brockman, D.K. 2003. Polyboroides radiatus predation attempts on
  Propithecus verreauxi. Folia Primatologia 74:71-74.
Dee, T.J. 1986. The endemic birds of Madagascar. International Council for
  Bird Preservation, Cambridge, UK.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Goodman, S.M., and M. Pidgeon. 1991. Madagascar Harrier-hawk
  Polyboroides radiatus preying on flying fox Pteropus rufus.
  Ostrich 62:215-216.
Karpanty, S.M. 2006. Direct and indirect impacts of raptor predation on
  lemurs in southeastern Madagascar. International Journal of Primatology
  27:239-261.
Karpanty, S.M., and S.M. Goodman.. 1999. Diet of the Madagascar
  Harrier-hawk, Polyboroides radiatus, in southeastern
  Madagascar. Journal of Raptor Research 33:313-316.
Kemp, A.C. 1994. Madagascar Harrier-hawk. P. 143 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.
Thorstrom, R., and G. La Marca. 2000. Nesting biology and behavior of the
  Madagascar Harrier-hawk (Polyboroides radiatus) in northeastern Madagascar.
  Journal of Raptor Research 34:120-125.
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., L.-A. René de Roland, and R.T. Watson. 2003. Falconiformes
  and Strigiformes: ecology and status of raptors. Pp. 1080-1085 in S.M.
  Goodman, and J.P. Benstead (eds.), The natural history of Madagascar.
  University of Chicago Press, Chicago, IL.
more....

Sites of Interest:
VIREO
Madagascar Harrier-hawk photo.

Researchers:
Thorstrom, Russell
Tingay, Ruth

Last modified: 7/1/2012

Recommended Citation: Global Raptor Information Network. 2014. Species account: Madagascar Harrier-hawk Polyboroides radiatus. Downloaded from http://www.globalraptors.org on 1 Aug. 2014








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