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  • This dataset contains the dive times (dive start time and dive end time) and depths (maximum depth attained on a dive) of three species of auk from the Isle of May outside the seabird breeding season. Data were collected from 12 Atlantic puffin individuals (Fratercula arctica), 13 common guillemot (Uria aalge) and 13 razorbill (Alca torda). Atlantic puffin data were collected between 19th July 2008 to 3rd December 2008; common guillemot data from 20th July 2005 to 28th January 2006; razorbill data from 1st July 2008 to 24th January 2009. Full details about this dataset can be found at

  • This dataset contains calculated return rates for five seabird species from representative colonies on the Isle of May, off the East coast of Scotland. Annual return rates are measured as the number of individually colour marked individuals seen in any one year that were also observed in the previous year for the Atlantic puffin (Fratercula arctica), common guillemot (Uria aalge), razorbill (Alca torda), European shag (Phalacrocorax aristotelis) and black-legged kittiwake (Rissa tridactyla). Not every individual is seen in any one year and the data set does not take into account those missed in any previous years hence these data are not to be treated as survival estimates. The Isle of May long-term study (IMLOTS) aims to identify the impact of environmental change on seabirds and their associated ecosystems. Understanding the mechanisms underlying variation in seabird population size requires a thorough knowledge of demographic parameters, namely birth rates, death rates, immigration and emigration. The effects of environmental change are likely to be different according to which demographic parameter or life history stage is being considered. This complexity means that only long-term monitoring, such as that carried out on the Isle of May, will allow us to understand the functioning of bird populations and their responses to environmental change. Full details about this dataset can be found at