Isle of May Long-Term Study

From the start in 1973, the Long-Term Study on the Isle of May (IMLOTS) has grown so that today it is the most data-rich and complex study of its type in Europe. IMLOTS forms part of CEH’s network of long-term monitoring sites for detecting effects of environmental change, particularly climate change. The study is partly funded by the UK’s Joint Nature Conservation Committee (JNCC) as part of the Seabird Monitoring Programme.

Why do we monitor seabirds?

There are at least two good reasons why we monitor seabirds:

For their own sake. The UK holds internationally important breeding populations of many species of seabirds, and therefore has an obligation to keep an eye on their well-being. 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. (Click here to read more.)

To accomplish this, we monitor many aspects of the biology of five species of seabirds breeding on the Isle of May: European shag, black-legged kittiwake, common guillemot, razorbill and Atlantic puffin. We use colour ringing to follow individuals and study their behaviour in detail. This means that for some individuals we know a lot about their entire life history – for an example of this, see the story of Yellow NP.

Repeated observations of colour-ringed individuals allow us to estimate the probability that a bird survives 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. Breeding success is more likely to respond to year-to-year changes in food supply. In combination, the monitoring of annual survival and breeding success allows us to understand the reasons why populations go up or down.

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

Kittiwake on nest

Breeding season summaries

Every year, we produce a summary of the breeding season for the JNCC:

We also regularly analyse our long-term data and report the results in scientific journals.

Recent publications

Reed, T.E.,  Daunt, F., Hall, M.E., Phillips, R.A., Wanless, S. & Cunningham, E. (2008) Parental responses to parasitism affect production of sons. Science Online

Daunt, F., Wanless, S., Greenstreet, S.P.R., Jensen, H., Hamer, K.C. & Harris, M.P. (2008) The impact of sandeel fishery closure in the northwestern North Sea on seabird food consumption, distribution and productivity. Canadian Journal of Fisheries and Aquatic Sciences, 65, 362-381

Frederiksen, M., Daunt, F., Harris, M.P. & Wanless, S. (2008) Stochastic weather drives survival and population dynamics in a long-lived seabird. Journal of Animal Ecology, 77, 1020-1029

Reed, T.E., Kruuk, L.E.B., Wanless, S., Frederiksen, M., Cunningham, E.J.A. & Harris, M.P. (2008) Reproductive senescence in a long-lived seabird: rates of decline in late-life performance are associated with varying costs of early reproduction. American Naturalist, 171, E89-E101.

Frederiksen, M, Jensen, H., Daunt, F., Mavor, R. & Wanless, S. (2008) Variable effects of a local sandeel fishery closure on breeding seabirds. Ecological Applications, 18, 701-710

Daunt, F., Afanasyev, V., Adam, A., Croxall, J. P. & Wanless, S. (2007). From cradle to early grave: juvenile mortality in European shags Phalacrocorax aristotelis results from inadequate development of foraging proficiency. Biology Letters, 3,371-374.

Lewis, S., Roberts, G., Harris, M.P., Prigmore, C. & Wanless, S. (2007) Fitness increased with partner and neighbour allopreening. Biology Letters, 3, 386-389.

Frederiksen, M., Edwards, M, Mavor, R A & Wanless, S (2007) Regional and annual variation in black-legged kittiwake demography is related to sea surface temperature. Marine Ecology Progress Series, 350, 137-143

Frederiksen, M., Mavor, R A & Wanless, S (2007) Seabirds as environmental indicators: the advantages of combining data sets. Marine Ecology Progress Series, 352, 205-211

Frederiksen, M., Furness, R. W. & Wanless, S. (2007) Regional variation in the role of bottom-up and top-down processes in controlling sandeel abundance in the North Sea. Marine Ecology Progress Series, 337, 279-286.

Harris, M. P., Beare, D., Toresen, R., Nøttestad, L., Kloppmann, M., Dörner, H., Peach, K., Rushton, D. R. A., Foster-Smith, J. & Wanless, S. (2007). A major increase in snake pipefish (Entelurus aequoreus) in northern European seas since 2003: potential implications for seabird breeding success. Marine Biology, 151, 973-983.

Wanless, S., Frederiksen, M., Daunt, F., Scott, B. E., & Harris, M. P. (2007) Black-legged kittiwakes as indicators of environmental change in the North Sea: evidence from long-term studies. Progress in Oceanography, 72, 30-38

Reed, T. E., Wanless, S., Harris, M. P., Frederiksen, M., Kruuk, L. E. B., & Cunningham, E. J. A. (2006) Responding to environmental change: plastic responses vary little in a synchronous breeder. Proceedings of the Royal Society, 273, 2713-2719.

Daunt, F., Afanasyev, V., Silk, J.R.D. & Wanless, S. (2006) Extrinsic and intrinsic determinants of winter foraging and breeding phenology in a temperate seabird. Behavioural Ecology & Sociobiology, 59,381-388

Lewis, S., Wanless, S., Elston, D. A., Schultz, M. D., Mackley, E., Du Toit, M., Underhill, J. G., & Harris, M. P. (2006) Determinants of quality in a long-lived colonial species. Journal of Animal Ecology, 75, 1304-1312.

Frederiksen, M., Edwards, M., Richardson, A. J., Halliday, N. C. & Wanless, S. (2006) From plankton to top predators: bottom-up control of a marine food web across four trophic levels. Journal of Animal Ecology, 75, 1259-1268.

Crespin, L., Harris, M.P., Lebreton, J.-D., Frederiksen, M. & Wanless, S. (2006) Recruitment to a seabird population depends on environmental factors and on population size. Journal of Animal Ecology, 75, 228-238.

Sims, M., Wanless, S., Harris, M.P., Mitchell, P.I., Elston, D.A. (2006) Evaluating the power of monitoring plot designs for detecting long-term trends in the numbers of common guillemots. Journal of Applied Ecology, 43, 537-546

Frederiksen, M., Harris, M.P. & Wanless, S. (2005) Inter-population variation in demographic parameters: a neglected subject? Oikos, 111, 209-214.

Frederiksen M, Wright PJ, Harris MP, Mavor RA, Heubeck M, Wanless S (2005) Regional patterns of kittiwake Rissa tridactyla breeding success are related to variability in sandeel recruitment. Marine Ecology Progress Series, 300, 201-211.

Harris MP, Anker-Nilssen T, McCleery RH, Erikstad KE, Shaw DN, Grosbois V (2005) Effect of wintering area and climate on the survival of adult Atlantic puffins Fratercula arctica in the eastern Atlantic. Marine Ecology Progress Series, 297, 283-296.

Wanless, S., Harris, M.P., Redman, P. & Speakman, J. (2005) Low energy values of fish as a probable cause of a major seabird breeding failure in the North Sea. Marine Ecology Progress Series, 294, 1-8.

Frederiksen, M., Wanless, S., Harris, M.P., Rothery, P. & Wilson, L.J. (2004) The role of industrial fisheries and oceanographic change in the decline of North Sea black-legged kittiwakes. Journal of Applied Ecology, 41, 1129-1139.

Wanless, S., Wright, P.J., Harris, M.P. & Elston, D.A. (2004) Evidence for decrease in size of lesser sandeels Ammodytes marinus in a North Sea aggregation over a 30-yr period. Marine Ecology Progress Series, 279, 237-246.