Adult survival rates of Shag (Phalacrocorax aristotelis), Common Guillemot (Uria aalge), Razorbill (Alca torda), Puffin (Fratercula arctica) and Kittiwake (Rissa tridactyla) on the Isle of May 1986-96

摘要: On the Isle of May between 1986 and 1996, average adult survival Shags Phalacrocorax aristotelis was 82.1%, Common Guillemots Uria aalge 95.2%, Razorbills Alca torda 90.5%, Puffins Fratercula arctica 91.6% Kittiwakes Rissa tridactyla 88.2%. Shags, all had a single year exceptionally low but these years did not coincide. In contrast, Kittiwake declined significantly over period there evidence that substantial non-breeding occurred in several years. Breeding success also declined, which gives rise to concern for its future status. Given high enough level resighting, return rates (the proportion birds known be alive one were seen next year) on year-by-year basis provide reasonable indication relative changes survival.