Wildlife Trust of South and West Wales Countryside Council for Wales Natural Environment Research Council University of Sheffield Skomer wardens and their partners Boatmen Numerous field assistants over 35 years ACKNOWLEDGEMENTS
Overall, a substantial increase in numbers since 1980 but still a long way off 1890s or 1930s levels
The Long-Term study of Guillemots on Skomer To understand what determines the numbers of guillemots Aims: 1. Annual survival - of adults & immature birds 2. Age of first breeding 3. Breeding success 4. Chick diet and feeding rate 5. Identify the factors affecting these
Effect of climate change on guillemot population parameters
North Atlantic Oscillation (NAO) a phenomenon associated with winter fluctuations in temperatures, rainfall and storminess. Positive NAO = westerly winds are stronger or more persistent, northern Europe tends to be warmer and wetter than average. Negative NAO = westerly winds weaker or less persistent, northern Europe tends to be colder and drier.
1950 1980 2000 From T. Osborn, Climate Research Unit, University of East Anglia NAO NAO: A general increase since 1980 but very variable
Adult guillemot survival decreases significantly with NAO
The Erika December 1999, 10,000 tons Brittany, Northern France OIL
When survival is 97% average breeding lifespan is 33 years When survival is 93% average breeding lifespan is 14 years Adult Survival Under normal conditions adult survival is 93-97% Oil incidents reduce survival to 87% = 7 year lifespan
Long term monitoring of population parameters provides 2. Early warning system 1. A much more sensitive assay of events than counts alone 3. Better understanding of the biology & reasons for change 4. A clear signal to the public of concern for populations
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