Mayr, Gerald http://orcid.org/0000-0001-9808-748X
Article History
Received: 13 March 2018
Revised: 22 May 2018
Accepted: 23 May 2018
First Online: 29 May 2018
Compliance with ethical standards
:
: The author declares that he has no conflict of interest.
: This study is exclusively based on museum specimens. Most of the birds stem from captivity and all died of natural causes. No birds were collected, killed or otherwise harmed in the course of the analysis.