1. University Centre Sparsholt, Sparsholt College Hampshire, Sparsholt, Winchester SO21 2NF, UK
2. Cotswold Wildlife Park, Bradwell Grove, Burford OX18 4JP, UK
3. Centre for Research in Animal Behaviour, Psychology, University of Exeter, Perry Road, Exeter EX4 4QG, UK
4. WWT Slimbridge Wetland Centre, Slimbridge, Gloucestershire GL2 7BT, UK