This dataset contains information on the parental behaviour, diet, condition and demography of common guillemots on the Isle of May, south-east Scotland. Annual data are available for 1982 to 2019 inclusive. These data are part of the Isle of May long-term study to assess population trends of seabirds under environmental change (IMLOTS https://www.ceh.ac.uk/our-science/projects/isle-may-long-term-study). Full details about this dataset can be found at https://doi.org/10.5285/f7676346-a67e-4fdf-9d30-e79ad2585195

This dataset contains prey items of common guillemot (Uria aalge) and razorbill (Alca torda) observed during the 2019 breeding season at East Caithness Special Protection Area (SPA), Buchan Ness to Collieston Coast SPA and Isle of May National Nature Reserve, off the east coast of Scotland. The diet of these two species has been studied on the Isle of May since the 1980s. To our knowledge, the only previous studies of diet were undertaken at Buchan Ness to Collieston Coast SPA (in 2006, 6km to the north of the site used in this study; and in 2017 & 2018, using a similar protocol as in 2019), and previous studies of diet have been undertaken at East Caithness SPA (2017 & 2018). Full details about this dataset can be found at https://doi.org/10.5285/3d90a2b0-9a9e-4e39-8986-9082d1ec529e