1. Department of Forest and Nature Management; Gembloux Agro Bio-Tech; University of Liège; Passage des déportés 2 5030 Gembloux Belgium
2. Mammal Research Institute; Polish Academy of Sciences; ul. Waszkiewicza 1 17-230 Białowieża Poland
3. Department of Natural and Agricultural Environmental Studies; Service Public de Wallonie; Avenue Maréchal Juin 23 5030 Gembloux Belgium
4. Institute for Terrestrial and Aquatic Wildlife Research; University of Veterinary Medicine; Bischofholer Damm 15 30173 Hannover Germany