BLACK SPARROWHAWKS SPOTTED ON WESTLAKE GOLF CLUB

It was really exciting to find Black Sparrowhawks breeding on your golf course, and to be able to identify the male as a chick that we ringed in 2006, in a garden off Southern Cross Drive in Constantia. We haven’t seen enough of his mate to be able to tell if she is ringed or not.

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The male was ringed on 8/11/2006 (1) and was next seen by Sue Harwood at Marina da Gama in July 2007 (4). As you can see from the picture he was beginning to get his adult plumage at the time.

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A few months later she managed to get another picture of him (5), this time in almost complete adult plumage. He was then seen in Lakeside several times, and then in 2008 Sharon Yodaiken saw him on Westlake Golf Course. I had already identified Westlake Golf Course as the most likely place for him to try and nest, so I can’t tell you how delighted I am that we have found him there. (6)

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On Black Sparrowhawks in general:

The adults come in two different types of plumage, their backs are black and their chests are either white or black (7 & 8). In Africa the white chested birds are common and the black chested are rare, but here on the Cape Peninsula the black chested ones make up more that 60% of the population.  The  juveniles are brown backed and red chested with dark streaks on the chest (3). The males are only two thirds the size of the females, and yet during the breeding season they do all the hunting for the family. If you think that they may have large three female chicks in the nest, a large wife and themselves to feed, then you can imagine how their endurance and strength is tested at this time. All in all, their breeding period takes up about 30 weeks of a year, slightly more than seven months. First the female becomes lethargic and the male starts providing her with food and building a nest. He is rewarded with being allowed to mate with her. One of the volunteers, who spent a lot of time at one nest noted “it is two sticks for a leg over” which turned out to be the going rate at all the other nests as well. Then after about 4-6 weeks she is ready to lay her eggs which take about 5 weeks to hatch. The chicks grow remarkably fast, taking only 6 weeks to develop from tiny creatures just out of the egg to being able to fly. Males are about 55 cm in length with a mass of 550 g, and females 60 cm in length with a mass of 850 g. The care of the young birds doesn’t end when they leave the nest because they are hunters and have to learn how to hunt. The parents spend three to four months with the fledglings teaching them this highly skilled activity. About 80% of their prey is pigeons and doves.

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Their most serious enemy is the Egyptian Goose. Geese don’t build their own nests but usually flatten an area in some grass or reeds, pluck some down from their chests, and lay their eggs. But they also realise that this puts them at the mercy of land predators, so if they can find a platform in a tree they are delighted to be able to nest safely off the ground (10).

The sparrowhawks can chase a goose off their nest if they act together, but if the goose’s mate gets into the act, then sparrowhawks lose their nest to the geese. If this happens the sparrowhawks have to start their breeding cycle all over again, and either wait for the geese to leave their nest or build a new one. In 2007 70% of nest failures were due to Egyptian Geese.  

Our project started in 2000 and we now have colour ringed over 130 birds. If anyone should see a ringed bird we would appreciate it if they could note which leg the colour rings are on, and which colour is on top of which (e.g. red over blue on right leg) and contact me at:

annkoeslag@cybersmart.co.za

072 357 0909   or   021 762 5347

Regards,

Ann Koeslag

Pictures of the bird nesting on Westlake Golf Course are: 1, 4, 5 and 6.
Pictures of birds from other areas to show various stages and plumages and what the rings look like are: 2, 3, 7, 8, 9.

Images 4 & 5 were taken by Sue Harwood.
All other pictures were taken by Ann Koeslag.