1. Terrestrial Ecology Unit, Department of Biology Ghent University Ghent Belgium
2. Department of Biology and Center for Environmental and Marine Studies University of Aveiro, Campus de Santiago Aveiro Portugal
3. Department of Ornithology Aranzadi Sciences Society Donostia Spain
4. Behavioral Ecology and Ecophysiology Group, Department of Biology, University of Antwerp, Campus Drie Eiken Antwerp Wilrijk Belgium
5. Research Institute for Nature and Forest Brussels Belgium