1. African Wildlife Conservation Fund, Chishakwe Ranch, Savé Valley Conservancy, Zimbabwe
2. Wildlife and Reserve Management Research Group, Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown/Makhanda, 6140 South Africa
3. Zoological Society of London, Regents Park, London, NW1 4RY, England
4. Department of Terrestrial Ecology, Norwegian Institute for Nature Research, Høgskoleringen 9, 7034 Trondheim, Norway