1. Percy FitzPatrick Institute of African Ornithology; University of Cape Town; Rondebosch 7701 Cape Town South Africa
2. Rhodes University; P.O. Box 94 Grahamstown 6140 South Africa
3. Institute of Zoology; Zoological Society of London; Regent's Park London NW1 4RY U.K.
4. Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment; University College London; London WC1E 6BT U.K.
5. ARC Centre of Excellence in Coral Reef Studies; James Cook University; Townsville Queensland 4811 Australia