Funding for this research was provided by:
Carl Tryggers Stiftelse för Vetenskaplig Forskning (CTS 15-74)
Article History
Received: 27 October 2017
Revised: 8 June 2018
Accepted: 14 June 2018
First Online: 26 June 2018
Compliance with ethical standards
: We performed the experiments and kept the birds under permit M-213-11 from the Malmö-Lund regional ethical permit board. We have followed all applicable national and international guidelines for the care and use of animals.
: The authors declare that they have no conflict of interest.