1. aMesserli Research Institute, University of Veterinary Medicine Vienna in collaboration with the University of Vienna and the Medical University of Vienna, Vienna, Austria
2. bMax-Planck-Institute for Ornithology, Seewiesen, Germany
3. cMax-Planck Comparative Cognition Research Station, Loro Parque Fundación, Puerto de la Cruz, Tenerife, Spain
4. dDepartment of Biology II, Ludwig-Maximilians-University of Munich, Munich, Germany