1. Wildlife Ecology Group, Massey University, Private Bag 11222, Palmerston North, New Zealand
2. Institute of Zoology, Zoological Society of London, Regent's Park, London, UK
3. Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
4. Parker Conservation, PO Box 130, Warkworth, Auckland, New Zealand