Hadeda mysteries unravelled
2006-11-09
A SWISS mountaineer, now assisting the Avian Demographic Unit (ADU) at the University of Cape Town, has been matching his skill with one of the largest swamp cypress trees in the Western Cape.
The tree in First Avenue, Paarl, is the home of a pair of Hadeda Ibis, a species that has become an increasingly frequent resident in many Paarl gardens of late.
The ADU is interested in their breeding and nesting habits and sent Dr Res Altwegg and his colleague, David Swanepoel, to scale the giant swamp cypress and ring the two fledglings that have so far escaped the ravages of the local African Harrier Hawks.
This was quite a daunting task, since no ladders could reach the nest high up in the branches. A handline had to be thrown across the top branches to provide a purchase for Dr Altwegg, who was then able to haul himself up in stages, branch by branch, to the nest. The fledglings were then lowered gently in a “bank bag” to the ground, where Swanepoel took the necessary measurements and attached a ring to each leg.
One of these is coloured red to assist spotters, the other is a Safring metal ring bearing a reference number.
In spite of their sharp, long beaks, the fledglings were not aggressive and did not seem to resent the undue handling. Once ringed, they were safely returned to their nest much to the delight of ma Hadeda (Lavinia), who did not much appreciate the interference of the Swiss mountain climber.
Hadeda Ibis were first recorded in the Western Cape some 46 years ago. By 1990 they had already established themselves as breeding residents. Their numbers have since increased rapidly and they are seen digging for food in parks, sportsfields and suburban gardens.
The ADU is trying to establish why they have proved so successful in a man-made environment. The three-year colour-ringing study started in September this year and will attract international interest.
The public is requested to report any red or yellow-ringed birds or active nests to Safring (tel 650-2421) or e-mail safring@adu.uct.ac.za. Queries may be directed to Doug Harebottle or Res Altwegg, co-ordinator of the project.
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