1. Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, the Netherlands
2. Behavioural Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
3. Interfaculty Mass Spectrometry Center, University of Groningen, the Netherlands
4. Laboratory Medicine, University Medical Center Groningen, University of Groningen, the Netherlands