-


Home | Species Database | Species Accounts | Bibliography | Researchers | Related Sites | Login


African Harrier-hawk
Polyboroides typus

Status: Lower risk

Population Trend: Stable.

Other Names: African Gymnogene, African Harrier Hawk, Banded Gymnogene, Banded Harrier-hawk, Bare-faced Whistling Hawk, Gymnogene, Gymnogenys typicus.


Polyboroides typus
click to enlarge
Distribution: Afrotropical. NIGER and SUDAN south to ZAIRE, ANGOLA, and SOUTH AFRICA. more....

Subspecies: 2 races. P. t. pectoralis: SENEGAMBIA east to western SUDAN, north to northwestern NIGER (Air Mountains) and south to ZAIRE; P. t. typus: East SUDAN to ERITREA and south to ANGOLA and SOUTH AFRICA. more....

Taxonomy: Formerly merged with the Madagascar Harrier-hawk (Polyboroides radiatus) under the latter name, but virtually all recent authors have considered the two forms to be separate species. 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. Wink and Sauer-Gürth (2004) found that this species clusters near the base of the Accipitridae, close to the Australian genera Hamirostra and Lophoictinia, based on analysis of cytochrome b nucleotide sequences. However, they noted that the affinities of Polyboroides remain unresolved. It is possibly closest to Melierax.

Movements: Partial migrant (Bildstein 2006). Sedentary in most parts of its range, but it is a wet season migrant in the Sahel zone, and there are movements into drier habitat in the non-breeding season in southern Africa. Immatures disperse from natal territories (Hockey et al. 1989).

Habitat and Habits: Occurs in a wide variety of open and forested habitat, ranging from semi-desert scrub to riparian woodlands to lowland rainforest and including exotic tree plantings in southern Africa. Occurs in the vicinity of oil palms (Elaeis) palms in Uganda (Carswell et al. 2005). It is often associated with cliff faces in mountainous or hilly terrain in South Africa, but it also occurs in flat plains (Boshoff 1997). Less common in more arid areas. Usually perches within cover. Occurs singly or in pairs. more....

Food and Feeding Behavior: Very opportunistic feeder, preying upon small mammals, frogs, lizards, and insects, which are found by climbing around on tree trunks and limbs, peering into crevices and holes while hanging at odd angles. This species has a reversible intertarsal ("knee") joint which can bend backward, as well as forward, enabling the bird to reach into deep holes to extract the contents. For prey that would otherwise be inaccessible, gymnogenes hang under branches and cliffs, balancing with flapping wings, and feeding on anything that they come across (Tarboton 1990). Raids nesting colonies of birds, especially ploceid weavers, taking eggs and nestlings. Also hunts on the wing, soaring or flapping slowly over open areas between trees. In West Africa and Malawi, it feeds on oil palm fruit, and it also takes carrion and fish. more....

Breeding: In southern Africa, most breeding activity occurs from September-March, and egg-laying is largely restricted to early summer (August-December, mainly September-October) (Boshoff 1997). Builds a stick nest, which is kept lined with green leaves and placed on rocks or trees, often on a slope, at the head of a ravine, or in riparian forest. Clutch size is 2 eggs, which are white and boldly blotched with dark reddish-brown markings. Parents share incubation and nest building duties. The incubation period is about 36 days, and the nestling period is about 52 days. Generally, only one chick survives, as the result of cainism (Tarboton 1990). more....

Conservation: Widespread and common throughout most of sub-Saharan Africa. One of the commonest birds of prey in forest and woodlands of West and Central Africa, especially where oil and Borassus Palms are abundant, and also abundant in southern Africa (Verdoorn and Roth 2000). This species has shown an ability to adapt to stands of alien trees in the latter region, which has allowed it to colonize some new areas. Categorized globally as a species of "Least Concern" by BirdLife International. more....

Important References: 
Boshoff, A.F. 1997. Gymnogene. Pp. 244-245 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.
Brown, L. 1972. The breeding behaviour of the African Harrier Hawk
  Polyboroides typus in Kenya. Ostrich 43:169-175.
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.
Kemp, A.C. 1994. African 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.
Smeenk, C., and N. Smeenk-Enserink. 1983. Observations on the Harrier Hawk
  Polyboroides typus in Nigeria, with comparative notes on the Neotropical
  Crane Hawk Geranospiza caerulescens. Ardea 71:133-143.
Steyn, P. 1982. Birds of prey of southern Africa: their identification and
  life histories. David Phillip, Cape Town, South Africa.
Thurow, T.L., and H.L. Black. 1981. Ecology and behaviour of the
  Gymnogene. Ostrich 52:25-35.
more....

Sites of Interest:
VIREO
African Harrier-hawk photos.


Last modified: 5/31/2012

Recommended Citation: Global Raptor Information Network. 2014. Species account: African Harrier-hawk Polyboroides typus. Downloaded from http://www.globalraptors.org on 17 Apr. 2014








Home | Species Database | Species Accounts | Bibliography | Researchers | Related Sites | Login

Copyright © 1999-2012 The Peregrine Fund. All Rights Reserved.
-