Author: Madre du Plessis

11 May 2012

Raptors, or birds of prey, always have some appeal to us because of their aerial antics and regal stance.  The Black Sparrowhawk is one of the stealthy hunters and has moved into the Western Cape over the past 20 years.  The availability of mature bluegum (eucalyptus) trees for nesting purposes has enabled this species to spread into the northern and southern suburbs.  There are a few territories adjacent to the Tygerberg Nature Reserve and one nest has been seen to produce offspring over the past three years.

The Black Sparrowhawk can be identified by its large size and black plumage, with a white chest and belly.  There is also a melanistic form where the black pigment is excessive and the white feathers are restricted to the throat and upper chest.  As is the case with most raptors, the female is substantially larger than the male.  These birds feed mainly on small birds, especially doves, but have been seen to take much larger prey up to the size of a Helmeted Guineafowl.

Black Sparrowhawks build a large nest platform high up in eucalyptus trees and lay between 2 and 4 eggs.   The incubation period is about 36 days, with both parents participating in brooding the clutch.  The youngsters remain in the nest for 37 to 47 days.  The male usually brings the food items, which are fed to the chicks by the female.  Once the fledglings have left the nest, they are dependent on their parents for food for a further 55 days.  The immature sparrowhawks’ plumage does not resemble that of their parents.  They have rich brown plumage, streaked with black, on their bellies and black feathers on the back and the folded wings.

At the onset of the breeding season one might be surprised by a sudden commotion in the vicinity of the sparrowhawk’s nest.  Egyptian Geese, which do not build their own nests, attempt to take over the nest platform for their own brood.  Squabbles often take place, accompanied with loud objections from the geese.  However, the aerial prowess and powerful talons of the sparrowhawks usually settle the disputes relatively quickly.