Funding for this research was provided by:
Norges Forskningsråd (221393, 223257)
the Norwegian Water resources and energy directorate
Received: 9 September 2019
Accepted: 25 November 2020
First Online: 17 December 2020
Ethics approval and consent to participate
: The field work was conducted with respect for the animals’ well-being and adheres to the Guidelines for the Use of Animals in Research [CitationRef removed]. It complies with the laws and regulations for animals used in research in Norway (FOR-2003-03-18-349, LOV-2009-06-19-100, LOV-1981-05-29-38§26). Ethical approval is not required for bird ringing (FOR-2003-03-18-349§§21-24), but Ringing licenses were issued and approved by the Norwegian Bird Ringing Centre on behalf of the Norwegian Environment Agency.
: Not applicable.
: The authors declare that they have no competing interests.