1. Department of Biology, Biodiversity unit, Lund University, Ecology Building, Lund 22362, Sweden
2. Cross River State Forestry Commission, Calabar, Nigeria
3. Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
4. Centre for Environmental and Climate Research, Lund University, Lund, Sweden
5. A.P. Leventis Ornithological Research Institute, Jos, Nigeria