1. Wildlife Conservation Research Unit, The Recanati-Kaplan Centre, Department of Biology, University of Oxford, Tubney House, Tubney, Abingdon OX13 5QL, UK
2. Department of Chemistry and Bioscience, Aalborg University, 9220 Aalborg, Denmark
3. Linacre College, University of Oxford, St. Cross Road, Oxford OX1 3JA, UK
4. Aalborg Zoo, 9000 Aalborg, Denmark
5. Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark