Institution: | Centre for Ecology and Hydrology, Monks Wood, Abbots Ripton, Huntingdon, Cambridgeshire PE28 2LS, UK; Edward Grey Institute of Field Ornithology, Department of Zoology, South Parks Road, University of Oxford, Oxford OX1 3PS, UK; Royal Society for the Protection of Birds, The Lodge, Sandy, Bedfordshire SG19 2DL, UK; British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU, UK |