[THIS DATASET HAS BEEN WITHDRAWN]. 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 https://doi.org/10.5285/53251b3c-6c79-4aeb-a0de-fc63b9350cc1

This dataset contains energy expenditure, sea surface temperature, foraging activity, day length, longitude, latitude, distance from the coastline and mass data from 17 common guillemots (Uria aalge) from the Isle of May during the 2016-2017 annual cycle. Full details about this dataset can be found at https://doi.org/10.5285/1cc5dcdb-e894-4973-a5b5-7a38a6cfc770

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. In the dataset, each year is represented by a single row of data, there are five columns showing the calculated return rates for each species (indicated by its common name and suffixed 'RR'). The figure quoted in any row is the proportion of marked birds which are observed by the end of the stated breeding season. Each row also contains the number of individuals seen in that year and the number seen in the previous year, taking into account new individuals which are marked. Full details about this dataset can be found at https://doi.org/10.5285/1624fe45-0deb-4bcd-9f13-75578693aaae

We tracked 94 common and 50 Brunnich's guillemots from five colonies around Iceland (Latrabjarg, Grimsey, Langanes, Skrudur and Papey) during late incubation and chick rearing from June to July 2019. We also tracked 5 common and 3 Brunnich's guillemots from Langanes during chick-rearing in July 2020 (GPS only). Finally, we tracked 4 common and 4 Brunnich's guillemots from Langanes during late incubation and chick rearing in June 2021. We used Pathtrack nanoFix GPS loggers to record locations every 3min and Cefas G5 TDR loggers to record depth every second. The tags recorded the birds' behaviour for a few days (typically 2 to 3). The aim was to investigate the foraging behaviour of the two species and the potential competition between them. Funding was provided by NERC grant NE/R012660/1 (part of the NERC Changing Arctic Ocean programme).