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.
Publication date: 2016-11-01
This dataset is part of the following
Data collected by CEH staff. All fieldwork, sampling and data handling was carried out by experienced and trained staff to defined protocols agreed to meet the objectives of the work. All data was collected in the field in notebooks and field data sheets. These were transcribed to spreadsheets after each check was made and files backed up to CEH directories. All notebooks and fieldsheets are archived at CEH Edinburgh.
The Isle of May is one of four key UK seabird monitoring sites supported by the JNCC (Joint Nature Conservation Committee). CEH has an on-going contract with JNCC to collect data on seabird demography and diet. The data, including that on annual breeding success, feed into the national Seabird Monitoring Programme network.