ACKNOWLEDGEMENTS
We are grateful to the inhabitants in our study area at the Helgeland coast, whose hospitality made this study possible. We also thank fieldworkers and laboratory technicians who contributed to generating the data used in the study. The empirical research was carried out in accordance with permits from the Norwegian Environment Agency and the Ringing Centre at Stavanger Museum, Norway. This study was supported by grants from the Research Council of Norway (project numbers 274930 and 302619). This work was also partly supported by the Research Council of Norway through its Centres of Excellence funding scheme (project number 223257). The authors declare no conflicts of interest.