1. BirdLife International, The David Attenborough Building, Cambridge CB2 3QZ, UK
2. Centre for Ecology and Conservation, University of Exeter, Penryn TR10 9FE, UK
3. Unidad de Investigación de Ecosistemas Marinos-Grupo Aves Marinas, Universidad Científica del Sur, Lima 15067, Peru
4. Lyell Centre, Heriot-Watt University, Edinburgh EH14 4BA, UK