Evans MI, Duckworth JW, Hawkins AFA, Safford RJ, Sheldon BC, Wilkinson RJSeptember 1992Journal article Journal:Bird Conservation InternationalVolume:2Issue:3, Cambridge University Press (CUP), pp.201 - 220No abstract availableKeywords:31 Biological Sciences , 41 Environmental Sciences DOI10.1017/s0959270900002446