J. Fuller & C. M. Ray, British Trustfor Ornithology, Beech Grove, Tring, Hertfordshire HP23 5NR,...
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J. Fuller & C. M. Ray, British Trustfor Ornithology, Beech Grove, Tring, Hertfordshire HP23 5NR, United Kingdom. P. Stuttard, Nature Conservancy Council, Blackwell, Bowness-on-Windermere,