1. Ecology Group, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand
2. New Zealand Wildlife Health Centre, Institute of Veterinary and Biomedical Sciences, Massey University, Private Bag 11-222, Palmerston North 4442, New Zealand
3. Research & Development Group, Department of Conservation, P.O. Box 10420, Wellington 6143, New Zealand