The Hadeda’s raucous call is unmistakeable. Loud, harsh and usually catching you by surprise. Hadedas were not indigenous to strandveld or renosterveld of the South Western Cape. Man-made changes in the form of cultivated agricultural fields, irrigated sports grounds and alien trees for nesting have made the environment more suitable to these birds’ requirements. This species moved into our area during the 1980’s and is now widespread.
The diet of this bird consists of a variety of insects, spiders, earthworms, snails and frogs. Prey items are either taken from the surface or captured by probing into soft soil. After good rains, groups of these birds may be seen on waterlogged sports grounds or cultivated fields where they gorge on insects that have been displaced by the standing water.
The Hadeda is somewhat of an oddball when compared with its cousins in South Africa. It is noisy, conspicuous and does not nest in colonies.
Pairs build nests in tall trees, often above streams or dams. The nest platform is an untidy bowl of sticks in which 2 to 4 eggs may be laid. Both parents incubate the eggs, which take between 25 to 28 days to hatch. Once the fledglings are able to clamber about they will leave the nest and can be seen perched ungainly on adjacent branches. The youngsters will take their first flight about 35 days after hatching and then join their parents when they roost in groups after the breeding season.
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.