1. Animal Demography Unit, Department of Biological Sciences, University of Cape Town, Cape Town, South Africa
2. Department of Biological Sciences, Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Cape Town, South Africa
3. Centre for Isotope Research, University of Groningen, Groningen, The Netherlands
4. Department of Biodiversity (Zoology), University of Limpopo, Sovenga,South Africa