Beaudouin’s snake-eagle  (Circaetus beaudouini)

Classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Previously considered a subspecies of the short-toed snake eagle, Circaetus gallicus, Beaudouin’s snake-eagle is a large eagle with a large, rounded head, fairly long wings, and a relatively long, square-ended tail. The body is grey brown above, with a dark head and chest, and the lower breast and belly are white, with thin, even brown bars. The whitish undertail bears three to four dark bands, and the underwings are also whitish, with some dark barring, and with dark tips to the primaries. The bare legs and feet are plain greyish-white, as is the facial skin, while the eyes are a striking and conspicuous yellow (2) (4) (5) (6).

The male and female Beaudouin’s snake-eagle are similar in appearance, while the juvenile is all dark or reddish-brown, with some white streaking on the head and barring on the flanks. The underparts, head and neck become paler and more mottled as the bird matures (2) (4) (6). Beaudouin’s snake-eagle can be distinguished from the closely related short-toed snake-eagle (C. gallicus)  by its smaller size, darker plumage, plainer underwings, more distinct tail bars and more even barring on the body, while the black-chested snake-eagle (Circaetus pectoralis) has a much darker hood and upperparts, and a plain white abdomen (2) (4) (5) (6).

Beaudouin’s snake-eagle occurs across a relatively narrow band of sub-Saharan Africa, from Senegal, Gambia and southern Mauritania in the west, to southern Sudan in the east, and south as far as northern Uganda. The species may also occur in Kenya, although its presence there is uncertain (2) (4) (5).

This species inhabits open woodland and wooded savanna, favouring areas of open grassland and even cultivated areas. A seasonal migrant, Beaudouin’s snake-eagle tends to move northwards in the rains and southwards in the dry season (2) (4) (5) (6).

Relatively little is kown about the biology of Beaudouin’s snake-eagle. Usually seen alone or in pairs (2) (4), it feeds mainly, as the name suggests, on snakes, although some lizards, small mammals, birds and occasional insects may also be taken. Breeding has been recorded from November to March in West Africa, but may occur over a more extended period further east. Beaudouin’s snake-eagle builds a small stick nest in a tree, and lays a single egg (2) (5) (6). The incubation period is thought likely to last around 45 days, the young eagle leaving the nest at around 70 days (2), but detailed information on these periods is lacking.

Despite its quite large range, Beaudouin’s snake-eagle has a relatively small population, which has undergone a dramatic decline in recent decades (4). In West Africa, the decline of this and other large birds of prey is thought to be associated with rapid human population growth, and the consequent destruction of habitat due to agriculture, overgrazing, woodcutting and urbanisation. Hunting pressure may also be a threat, while the use of pesticides is likely to have depleted insects which were previously an important food source for raptors or their prey. In addition, overgrazing of livestock is a major cause of desertification in the Sahel region (4) (7) (8).

Beaudouin’s snake-eagle is listed on Class B of the African Convention on the Conservation of Nature and Natural Resources, meaning it should only be killed or captured with special authorisation (9), and international trade in the species should be regulated under its listing on Appendix II of the Convention on International Trade in Endangered Species (CITES) (3). Beaudouin’s snake-eagle occurs in a number of protected areas in West Africa, which have been shown to be of vital importance to its conservation (4) (7) (8). However, such areas currently only cover under two percent of the region (4) (8). Further population surveys, investigation into the threats the species faces, and protection of the remaining habitat will all be important for the future survival of this large eagle (4).

View information on this species at the UNEP World Conservation Monitoring Centre.

To find out more about Beaudouin’s snake-eagle and its conservation see:

• BirdLife International:
  http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=31639&m=0
• Ferguson-Lees, J. and Christie, D.A. (2001) Raptors of the World. Helm Identification Guides, A & C Black Publishers, London.