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Brown Snake Eagle
Circaetus cinereus

Status: Lower risk

Population Trend: Stable.

Other Names: Brown Harrier-eagle, Brown Snake-eagle.

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Circaetus cinereus
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Distribution: Afrotropical. SENEGAMBIA east to northern ETHIOPIA and south to SOUTH AFRICA. more....

Subspecies: Monotypic.

Taxonomy: According to the molecular study of Lerner and Mindell (2005), which was based on the molecular sequences of two mitochondrial genes and one nuclear entron, the snake eagles of the genus Circaetus form a monophyletic group that is sister to the Old World vulture group, Aegypiinae, as was found earlier by Wink (1995). They are also related to the Congo Serpent Eagle (Dryotriorhis spectabilis), but not to the Madagascar Serpent Eagle (Eutriorchis astur).

Movements: Irruptive or local migrant, with juveniles dispersing from breeding areas (Bildstein 2006). Nomadic and seasonal movements have been documented in several areas, e.g., in southwestern and eastern Cape Province, where it is known only a a non-breeding visitor or vagrant. In West Africa, this species moves north with the rains and south in the dry season (Borrow and Demey 2001). Some individuals must wander widely, as a bird ringed on 3 March 1974 at Assen in the Northern Province of South Africa was recovered almost seven years later 2,100 km north in the Democratic Republic of the Congo by a missionary, who was told by villagers that the bird "died in a fight with a big snake" (Oatley et al. 1998). more....

Habitat and Habits: Occurs in moderately arid open and dense woodland, including dry thorn and broad-leafed savannas, and dense Brachystegia woodland (Brown et al. 1982), but is absent from very arid steppe and grassland. Prefers more wooded regions than its open country congener, the Black-breasted Snake-eagle (Jenkins 1997). Spends most its time perched in a prominent tree or on an electricity pylon. Occurs mostly singly, but sometimes in pairs, and never in large communal roosts like the Black-breasted Snake Eagle. more....

Food and Feeding Behavior: Feeds almost exclusively on snakes, particularly venomous species, but occasionally takes lizards and other small vertebrates. Captures prey by gliding or parachuting down from an exposed tree perch to the ground. more....

Breeding: Builds a small stick nest which is well hidden in the top of a densely forested tree, or in a mass of epiphytes. The nest is kept lined with green foliage throughout the incubation period. Clutch size is one egg. The female does most or all of the incubation, and the male provides her with food. The incubation period is 50 days (long for a species this size), and the nestling period is 100 days (Tarboton op cit.). The same nest is rarely used twice, probably reflecting the nomadic habits of this species (Tarboton 1990). more....

Conservation: Widespread over sub-Saharan Africa, but generally uncommon in most areas. It is probably affected by habitat destruction, but there is no specific information about its population trends. It is not threatened in southern Africa, but its higher densities in protected areas suggests that it is susceptible to habitat destruction and/or human disturbance outside reserves (Jenkins 1997, Simmons 2005). Categorized globally as a species of "Least Concern" by BirdLife International. more....

Population Estimates: Ferguson-Lees and Christie (2001) estimated the global population at the start of the breeding season at 10,000 to 1000,000 individuals. BirdLife International also estimated the number of mature individuals at 10,000 to 100,000 birds, but noted that the supporting data for this estimate are poor. more....

Important References: 
Brown, L.H., E.K. Urban, and K. Newman. 1982. The birds of Africa. Vol. 1.
  Academic Press, London.
Ferguson-Lees, J., and D.A. Christie. 2001. Raptors of the world. Houghton
  Mifflin, Boston, MA.
Jenkins, A.R. 1997. Brown Snake Eagle. Pp. 196-197 in J.A. Harrison et al.
  (eds.), The atlas of South African birds. Volume 1: Non-passerines. BirdLife
  South Africa and Avian Demography Unit, Johannesburg, South Africa.
Kemp, A.C. 1994. Brown Snake-eagle. Pp. 132 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.
Simmons, R.E. 2005. Brown Snake-Eagle Circaetus cinereus. Pp. 494-495 in
  P.A.R. Hockey, W.R.J. Dean, and P.G. Ryan (eds.), Roberts Birds of Southern
  Africa. 7th ed. Trustees of the John Voelcker Bird Book Fund, Cape Town,
  South Africa.
Snow, D.W. 1978. An atlas of speciation in African non-passerine birds.
  Trustees of the British Museum (Natural History), London.
Steyn, P. 1982. Birds of prey of southern Africa: their identification and
  life histories. David Phillip, Cape Town, South Africa.

Sites of Interest:
Brown Snake Eagle photos.

Middleton, Angus
Simmons, Rob
Steyn, Peter

Last modified: 6/1/2012

Recommended Citation: Global Raptor Information Network. 2020. Species account: Brown Snake Eagle Circaetus cinereus. Downloaded from http://www.globalraptors.org on 25 Sep. 2020

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