1. PiedFly.Net; Yarner Wood Bovey Tracey Devon TQ13 9LJ UK
2. British Trust for Ornithology; The Nunnery Thetford Norfolk IP24 2PU UK
3. Centre for Research in Animal Behaviour; College of Life & Environmental Sciences; University of Exeter; Devon EX4 4QG UK
4. RSPB Centre for Conservation Science; The Lodge Sandy Bedfordshire SG19 2DL UK