1. Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3DA, UK
2. Montgomeryshire Wildlife Trust, Park Land House High Street, Welshpool, SY21 7JP, UK
3. Department of Physical Sciences, Earth and Environment, University of Siena, Via Mattioli 4, 53100 Siena, Italy
4. Latvian Fund for Nature, Dzirnavu 73-2, Riga, LV-1011, Latvia
5. Mid Wales Ringing Group, Nantmel, LD16EN, UK
6. Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Penglais, Aberystwyth, Ceredigion, SY23 3DA, UK