1. Senckenberg Research Institute and Natural History Museum Frankfurt, Ornithological Section, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany.
2. Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6, Canada.
3. Department of Natural History, Royal British Columbia Museum, 65 Belleville Street, Victoria, BC V8W 9W2, Canada.
4. Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA 02138, USA.