1. Environmental Research Institute, UHI North Highland , Thurso, Caithness , UK
2. Bird Group, Department of Life Sciences, The Natural History Museum , Tring, Hertfordshire , UK
3. Department of Ecoscience, Aarhus University , Roskilde , Denmark
4. Department of Ecoscience, Aarhus University , Aarhus , Denmark
5. Seabird Ecology Department, Faroe Marine Research Institute , Tórshavn , Faroe Islands
6. Norwegian Polar Institute, Fram Centre , Stakkevollan, Tromsø , Norway
7. Brautarland , Reykjavik , Iceland
8. Department of Arctic Ecology, Norwegian Institute for Nature Research , Trondheim , Norway