1. Department of Zoology; University of Cambridge; Cambridge CB2 3EJ UK
2. Department of Land Economy; University of Cambridge; Cambridge CB3 9EP UK
3. Department of Crop and Environment Sciences; Harper Adams University; TF10 8NB UK
4. United Nations Environment Programme World Conservation Monitoring Centre; 219 Huntingdon Road Cambridge CB3 0DL UK
5. School of Life Sciences; University of Sussex; Falmer Brighton BN1 9QG UK
6. British Trust for Ornithology; The Nunnery; Thetford IP24 2PU UK
7. Centre for Environmental and Climate Research; Lund University; S-22362 Lund Sweden