1. Institute of Biological and Environmental Sciences, School of Biological Sciences, Zoology Building, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, UK
2. Centre for Applied Conservation Research, Forest Sciences, 2424 Main Mall, University of British Columbia, Vancouver, Canada V6T 1Z4
3. Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland