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
On the Isle of May between 1986 and 1996, the average adult survival of Shags Phalacrocorax aristotelis was 82.1%, Common Guillemots Uria aalge 95.2%, Razorbills Alca torda 90.5%, Puffins Fratercula arctica 91.6% and Kittiwakes Rissa tridactyla 88.2%. Shags, Razorbills and Puffins all had a single y...
| Main Authors: | , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
2000
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| Subjects: | |
| Online Access: | http://nora.nerc.ac.uk/id/eprint/5123/ http://www.seabirdgroup.org.uk/?page=journalcontents&vol=2&no=3 |
| Summary: | On the Isle of May between 1986 and 1996, the average adult survival of Shags Phalacrocorax aristotelis was 82.1%, Common Guillemots Uria aalge 95.2%, Razorbills Alca torda 90.5%, Puffins Fratercula arctica 91.6% and Kittiwakes Rissa tridactyla 88.2%. Shags, Razorbills and Puffins all had a single year of exceptionally low survival but these years did not coincide. In contrast, Kittiwake survival declined significantly over the period and there was evidence that substantial non-breeding occurred in several years. Breeding success of Kittiwakes also declined, which gives rise to concern for its future status. Given a high enough level of resighting, return rates (the proportion of birds known to be alive one year that were seen the next year) on a year-by-year basis provide a reasonable indication of relative changes in adult survival. |
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