EVOLUTION 



Fig. gb 



The distribution of bridled guillemots in the East Atlantic breeding-populations: 



O: no bridled birds observed. A: under i per cent bridled. B: under 2 per cent bridled. C: under 



5 per cent bridled. D: under 10 per cent bridled. E: under 20 per cent bridled. F: under §0 per 



cent bridled. G: over ^o per cent bridled. 



