1. Konrad Lorenz Institute of Ethology, Department of Integrative Biology and Evolution, University of Veterinary Medicine, Vienna, Austria
2. Laboratoire Évolution & Diversité Biologique (EDB), UMR 5174 CNRS-UPS-IRD, Toulouse, France
3. ENSFEA, Castanet-Tolosan, France
4. Institute for Seabird Research and Conservation, Anchorage, AK, USA