Isle of May landscape
Isle of May Long-Term Study (IMLOTS)

Science challenge

The UK holds internationally important breeding populations of many species of seabirds, and therefore has an obligation to monitor their well-being. Seabird population dynamics are also a highly useful indicator of the health of marine ecosystems and environmental change. For example, analysis of data from the Isle of May confirmed that numbers of black-legged kittiwakes have declined by more than half since 1990 and linked this decline to ongoing climate change.

Project summary

The Isle of May Long-Term Study (IMLOTS) began in 1973 and is the most data data-rich and complex study of its kind in the UK.

The Isle of May, situated in the entrance to the Firth of Forth on the east coast of Scotland, is a National Nature Reserve, recognised for its rich bird life. The breeding success of many of the bird species found there is influenced by climate change, via effects on their food sources.

In IMLOTS, we monitor many aspects of the biology of five seabird species breeding on the island:

  • European shag
  • Black-legged kittiwake
  • Common guillemot
  • Razorbill
  • Atlantic puffin.

Birds are ringed and the behaviour of individuals are studied in detail. Repeated observations allow us to predict bird survival from year to year, the main factor affecting population growth in these long-lived birds. We also follow breeding success, measured as the average number of chicks fledged per breeding pair.

To understand year-to-year variation in more detail, we also monitor the food that adults bring to their chicks. Variation in the importance or size of different fish species, or in fish age classes, can have important repercussions for the birds and tell us a lot about sea conditions.

The study is partly funded by the UK’s Joint Nature Conservation Committee (JNCC) as part of the Seabird Monitoring Programme. 

The IMLOTS team are also involved in a range of related projects (see below).


  • To undertake world class strategic research to deliver process-based understanding of drivers of change in seabird populations and coastal ecosystems
  • To provide evidence for the major societal challenge of sustainable economic use of UK coastal waters, in particular the delivery of marine renewable developments and fisheries while fulfilling the UK’s legal obligations under national and international environmental protection directives.



Research facilities

  • A field research platform at which to study seabirds and other components of UK coastal marine ecosystems that is used for numerous university projects and is the central hub of a national network of long-term seabird monitoring sites.


UKCEH national capability

  • IMLOTS makes a valuable contribution to UK-SCAPE’s activities on monitoring, data science, projections of environmental impacts and stakeholder engagement
  • Investigations of cross-system pressures can be undertaken in collaboration with UKCEH's other long-term monitoring studies (e.g. Burthe et al, Journal of Applied Ecology 2016).


  • IMLOTS collaborates with other National Capability activities undertaken by British Antarctic Survey, Plymouth Marine Laboratory and National Oceanography Centre.

Project lead - Dr Francis Daunt

Prof. Sarah Wanless