1. a Dept. of Ornithology , National Museum , P.O. Box 266, Bloemfontein, 9300
2. b P.O. Box 313, Knysna, 6570, South Africa
3. c Percy FitzPatrick Institute of African Ornithology , University of Cape Town , Rondebosch, 7700, South Africa
4. d Department of Ornithology , National Museum , P.O. Box 266, Bloemfontein, 9300
5. e Dr Guepinlaan 23, 4032, NH, Ommeren, Holland
6. f Dokter Guepinlaan 23, 4032, NH, Ommeren, Holland
7. g Lehrstuhl für Tierphysiologie , Universität Bayreuth , 8580, Bayreuth