Regional and annual variation in black-legged kittiwake breeding productivity is related to sea surface temperature

Spatiotemporal variation in seabird demographic parameters is often pronounced and be an important source of information on the state of marine ecosystems. Black-legged kittiwakes tridactyla in Britain and Ireland show strong regional structure in breeding productivity, both temporal and spatial variation are probably related to abundance of the principal prey of kittiwakes, the lesser sandeel Ammodytes marinus. Annual regional estimates of sandeel do not exist, prohibiting direct tests of this hypothesis. We examined relationships kittiwake breeding productivity and 2 potential proxies of sandeel abundance, winter sea temperature (SST) and abundance of Calanus copepods, within and among 6 regions in and Ireland from 1986 to 2004. Means and trends in winter SST differed among regions, with means and less pronounced increasing trends in western (Atlantic) regions than in eastern (North Sea) regions. A negative relationship between breeding productivity and winter SST in the year was found within 2 regions (East Scotland and Orkney), as well as in a cross-regional . Results were inconclusive for Calanus abundance, with a positive relationship in East Scotland negative in Orkney. These results demonstrate that although a single environmental driver (SST) is related to both within- and between-region variation in a key demographic parameter, heterogeneity in SST trends as well as the importance of other factors may lead to highly responses. Understanding this heterogeneity is critical for predicting long-term effects of change or other anthropogenic drivers on marine ecosystems.