1. School of Veterinary and Life Sciences, Murdoch University, South Street, Murdoch, Western Australia 6050, Australia
2. Current address: Wildlife Management Branch, Department of Primary Industries, Parks, Water and Environment, 134 Macquarie St., Hobart, Tasmania 7000, Australia
3. Department of Environment and Conservation, Western Australian Wildlife Research Centre, P.O. Box 51, Wanneroo, Western Australia 6946, Australia