Affiliation: | Royal Society for the Protection of Birds, Dunedin House, 25 Ravelston Terrace, Edinburgh EH4 3TP, UK; Centre for Ecology and Hydrology, Hill of Brathens, Banchory, Aberdeenshire AB31 4BW, UK; Royal Society for the Protection of Birds, 12–14 North End Road, Stromness, Orkney KW16 3AG, UK; Scottish Natural Heritage, 2 Anderson Place, Edinburgh EH9 2AS, UK |