1. BTO Scotland, Beta Centre Unit 15, Stirling University Innovation Park, Stirling, FK9 4NF
2. British Trust for Ornithology, The Nunnery, Thetford, Norfolk IP24 2PU
3. Comers Wood Croft, Midmar, Inverurie, AB51 7QB
4. CEFE UMR 5175, Univ Montpellier, CNRS, EPHE, IRD, Univ Paul Valéry Montpellier 3, 1919 route de Mende, 34293 Montpellier cedex 5, France
5. School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ