AFRICAN HARRIER-HAWKS (Gymnogene)
take up residence on the Greater Woodmead Estate…
Our Golf Professional and enthusiastic birdwatcher, Owen Grobler recently reported seeing a pair of African Harrier-hawks constructing a nest high up in a blue gum tree on the Woodmead course. This pair of Harrier-hawks have hunted and foraged over the Greater Woodmead Estate for many years and have had their nest site in the Sandspruit river valley a mere 500 meters away to the west of the Bowling avenue boundary. They have now decided in their more senior years – for those few extra minutes of shut eye, to move closer to their hunting ground, and take up residence on Woodmead and raise their next brood.
The relocation of their nesting site left us with a dilemma. The Environment Committee had gained approval to wean out the alien trees, notably blue gums and wattles, on the western front and now the chain saws were advancing in the direction of the new nest site!
A quick call was made to Geoff Lockwood, an old friend of CCJ, to survey the site. He was expecting an American Birdwatchers group and was not available at short notice but suggested we contact Mark Anderson, the CEO of Birdlife and a raptor specialist. Mark made himself immediately available and arrived with his wife Tania, a botanist and also with Birdlife, early one morning on our recent public holiday.
Suspension of the chain saws was never in doubt. Mark in turn consulted with Dr. Warwick Tarboton, who many of our CCJ members know, with regard to post breeding rehabilitation of the surrounding indigenous flora. His recommendation was that for a period of three months all rehabilitation of the close surrounding flora be suspended and that thereafter only the alien undergrowth be removed under the tall majestic blue gums, in order to preserve the nest site for future use.
The African Harrier-hawk, also known as the Gymnogene or Bare-faced Hawk with blue-grey plumage, a small head, yellow facial mask and with a prominent tail bar is one of the most unusual and specialized birds of prey in Southern Africa. From a prey point of view, one of the most feared raptors due to its remarkable ‘double jointed knees’, which not only bend forwards but backwards and also sideways. Due to this adaption, its long legs can be inserted into holes in trees to extract nestlings of hole nesting species such as woodpeckers, barbets, starlings as well as small reptiles and squirrels.
The African Harrier-hawk has an ability to hang or ‘walk upside down’ for quite long periods and flaps its wings loosely while doing so. It can ‘run’ up trunks of trees with flapping wings searching in crevices and holes. Its’ very small head makes this possible as it hunts out its prey. Whilst it forages mainly in trees it may also hunt on foot in the open ground and often some distance from the nearest cover.
The various adaptions of the Harrier-hawk enables it to fill an ecological niche where it has little competition from other raptors. While breeding the male feeds the female as part of courtship, depositing prey on the nest or giving it to her directly. The bare facial skin of both the birds flush red during courtship and when excited.
During nest building, which we have witnessed, prey has also been deposited at the nest site and whilst the pair have been away searching for nest building material the crows have been raiding the nest site for morsels.
There is considerable time being spent mating and as a matter of interest the other nest site also in a eucalypt in the Sandspruit, has not been rehabilitated so it bodes well for us that they will stay on our estate.
One or two eggs will be laid and are the most beautifully marked eggs of all the raptors in Southern Africa, being creamy white, and often with red-brown blotches almost the colour of mahogany. Incubation will be for 35 days followed by a developing fledgling period of 45 days and so our family will be with us until mid-November when the juvenile fledges and then one will be able to see a non-descript brown bird with yellow legs and small head hanging around the nest crying for food before eventually being chased away by its parents.