1. Game Conservancy Trust, Institute of Cell, Animal and Population Biology, University of Edinburgh, Edinburgh EH9 3JT, UK
2. Institute of Terrestrial Ecology, Banchory, Kincardinshire AB31 4BY, UK
3. Centre for Tropical Veterinary Medicine, University of Edinburgh, Edinburgh EH25 9RG, UK
4. Institute of Terrestrial Ecology, Monks Wood, Cambridgeshire PE17 2LS, UK
5. Institute of Biology, University of Stirling, Stirling FK9 4LA, UK