1. From the General and Systematic Zoology, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
2. Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
3. Vogelwarte, Zoological Institute and Museum, University of Greifswald, Greifswald, Germany
4. Department of Biological Sciences, University of Cape Town, Rondebosch, Cape Town, South Africa