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African Harrier Hawk (or Gymnogene or African Gymnogene)
Polyboroides typus

Accipitriforme Order – Accipitridae Family 

BIOMETRICS:
Length: 60-66 cm; Wingspan: 160 cm ; Weight: 635-950 g

DESCRIPTION:
Gymnogene is a medium sized raptor. Upperparts, head and breast are pale grey. Belly is finely barred with black and white. It has broad pale grey wings, with edge fringed with narrow white line, and black spots on the wing coverts. A broad white band crosses the black tail.
Gymnogene has a bare facial patch, variable in colour, but often bright yellow. When it calls near the nest, this patch becomes pink, and during display, face becomes almost red, with various shades of orange between yellow and red.
Eyes are dark brown. Hooked short bill is black. Feet and legs are yellow, and double-jointed, with smallish feet.
Both sexes are similar.

VOICE: SOUNDS BY XENO-CANTO
Gymnogene’s call is a weak, plaintive and prolonged whistle “su-eeeee-oo”. But usually, it is a silent bird.
Young at nest make a more high-pitched call, a rapid chattering “ki-ki-ki-ki-ki”, while adults utter a “wheep-wheep” near the nest.

HABITAT:
Gymnogene lives in woodland areas, forests, savannahs and cultivated areas, close to water, or in rainy areas, from sea level to 3000 metres elevation.

RANGE:
Gymnogene lives in Africa, South of Sahara. In southern Africa, it is locally common resident, but absent from the drier parts of the country.

BEHAVIOUR:
Gymnogene is usually solitary. It is specialized in robbing nests of holes nesting birds, with its adaptive flexible knee-joints to facilitate this habit. It can probes crevices and hollows for lizards and larvae, but when it robs weaver’s nests, it hangs upside-down to catch chicks and eggs.
To feed on oil palm nuts, it may walk along branches and foliages, feet over feet, using its wings to stabilize it.

Gymnogene hunts mainly in trees and bushes, but not on the wing. It performs hunting in weaver bird colonies to probe their nests.
It hunts by soaring, searching from a perch or walking on the ground, or over tree trunks, flapping loosely its wings. It invades waterbirds colonies to eat young and eggs, and may perform a low coursing flight across vegetation. 
Its tarsal joint bends forwards, backwards and sideways, making it unique. Its small head allows it to extract some preys from crevices.
During courtship display, female flies turning on its back in order to present her talons to the male.    

FLIGHT:
Gymnogene soars easily and steadily. In flight, it appears very buoyant, with its broad and rounded wings. Usually, it flies high over the forest, with a slow and buoyant flight.

REPRODUCTION:
Gymnogene breeds at the end of the dry season, from June to November. Its nest is located at the top of a tree, or in a rocky crevice near the ground.  
The nest is a stick platform, with a rim of green fresh leaves, and lined with green sprigs.
Female lays 1 or 2 white eggs. Incubation lasts about 35 days, by both parents. Chicks are fed by both adults, mainly by female with food brought at nest by male. They fledge at about 45 to 55 days.

DIET:
Gymnogene feeds on chicks and eggs of small birds. But it also eats frogs, insects, small mammals and reptiles, and bats. Sometimes, when available, it may consume oil palm fruit. 

 

PROTECTION / THREATS / STATUS:
Gymnogene is widely distributed in sub-Saharan Africa, except in the arid northern regions. 

Fr: Gymnogène d’Afrique
All : Höhlenweihe
Esp: Aguilucho-caricalvo Común
Ital: Sparviero serpentario africano
Nd: Kaalkopkiekendief
Russe: Африканский луневый ястреб

Photographs by Yves Thonnérieux (Adult birds)
His website : NATUR’AILES

Photograph by Steve Garvie (Immature bird)
His website : RAINBIRDER Photo galleries

Text by Nicole Bouglouan

Sources:

HANDBOOK OF THE BIRDS OF THE WORLD Vol 2 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334156

BIRDS OF PREY OF AFRICA AND ITS ISLANDS by Alan and Meg Kemp - Struik Publishers - ISBN: 1770073698

BIRDS OF AFRICA SOUTH OF THE SAHARA by Ian Sinclair and Peter Ryan - Princeton University Press Princeton and Oxford - ISBN: 0691118159

Avibase (Lepage Denis)

The Hawk Conservancy Trust (Hilary Smith)

Wikipedia (Wikipedia, The Free Encyclopedia)

 

Home page

Page Birds of Prey

Summary cards

 

Juveniles have pale brown plumage, paler on belly, with dark brown instead black and barred tail.
Chicks are downy buff to orange-brown, and at about 10 days, they are greyish above and white below. They have pale olive grey cere and face whereas legs and feet are greenish yellow.
Immature

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