1. Laboratory of Applied Biology and Ecology, Faculty of Science, University of Dschang, Dschang, Cameroon
2. Department of Fundamental Science, Higher Technical Teacher Training College, University of Bamenda, Bambili, Cameroon
3. School of Biological and Environmental Sciences, University of Stirling, Stirling FK9 4LA, UK
4. Centre for Conservation Science, Royal Society for the Protection of Birds, The Lodge, Sandy, SG19 2DL, UK