Found off the south-west coast of Wales, UK, Skomer Island is a National Nature Reserve managed by The Wildlife Trust of South and West Wales. Less than 3km2, this remote island is home to the world’s largest population of Manx Shearwaters, 6000 breeding pairs of Puffins, and is the only known habitat of the Skomer Vole. A naturalist’s paradise, Skomer is rich in seabirds (eg. Guillemots, Razorbills, Kittiwakes, Fulmars, Manx Shearwaters, Puffins, gulls), birds of prey (eg. Short-Eared Owls, Kestrels, Buzzards, Peregrine Falcons), seals, porpoises, butterflies and stunning flora. Skomer is no longer permanently inhabited, but a team of wardens, assistants and volunteers help the hundreds of visitors as well as several important research projects.
Guillemot Population Study
In 1930’s, there were around 100,000 guillemots on the island’s cliffs, but by the early 1970’s there were just 2000 birds remaining. The population is now around 20,000 individuals and increasing, possibly due to overfishing of large fish leading to an increased number of the smaller fish which guillemots eat (sprats). Since 1972, Tim Birkhead and Ben Hatchwell (also at the University of Sheffield) have studied an individually marked population of guillemots on Skomer Island. Aiming to understand population fluctuation, our group monitor adult and chick survival, reproductive success, timing of breeding, and the diet of the guillemot population. Long-term studies such as this are vital to understand the health of the population and the state of the marine environment, and to recognise the effects of climate change and oil pollution on the ecosystem. (See: Votier et al. (2005) Ecology Letters, 8: 1157-1164, and Meade et al. (2012) J. Avian Biology, 43: 1-7.)
Whole island and sub-colony counts of guillemots from 1963 to 2012.
Guillemots can live for 20-30 years, and generally return to breed at the same site each year. They produce a range of beautifully coloured eggs, each colour and pattern combination unique to each female. They can dive up to 180m into the sea to catch their fish prey, before crash-landing back into their densely packed cliff colonies.