1. School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
2. Biomolecular Interaction Centre, University of Canterbury, Private Bag 4800, Christchurch 8041, New Zealand
3. Electron Microscope Unit, University of Cape Town, Rondebosch, 7701 Cape Town, South Africa
4. Department Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard Gwinnerstr, 82319 Seewiesen, Germany