In 1986, St Kilda was inscribed by UNESCO as a World Heritage Site in recognition of its Natural Heritage; for its exceptional natural beauty and for the significant natural habitats that it supports.
Earlier this month, the National Trust for Scotland celebrated the 30th anniversary of this designation and launched the ‘Love Our Islands’ appeal to support important conservation and ecological work at the archipelago. Caring for St Kilda costs our charity around £270,000 annually. Monies are used for all manner of works including the upkeep and preservation of manmade dwellings such as the iconic street, the church and Factor’s House, approximately 1400 cleits, enclosures and miles of drystane walling and to fund monitoring work of our important seabird colonies.
St Kilda is the largest seabird colony in the north-east Atlantic, with something in the region of 600,000 birds nesting each year across seven islands within the archipelago. Ecological studies of the seabird populations here have shown its increasingly vital role as a bellwether for the condition of our climate and seas. Full counts of all of the seabirds in the colony take place at intervals of around 15 years, with the most recent taking place over the last two years. In the intervening years the seabird ranger – me! - carries out routine monitoring of small sub-sections of the colony that helps to build a picture of shorter term trends in numbers.
The most recent survey concentrated on the cliff nesting species. The results make sombre reading as there were significant declines recorded for all species, namely: Black-legged Kittiwakes, Northern Fulmars, Razorbills, Common Guillemots and European Shags. But, it is the Kittiwake population that has suffered most severely with a 90% reduction in the number of breeding sites.
Rising water temperatures caused by climate change have been implicated in these declines as changing oceanic conditions make the marine life on which the birds feed harder to access. Of course, in ecology, it is rarely this simple and there are likely to be other causal factors that affect the size of the colonies at St Kilda.
Over the next couple of years, we would like to complete whole archipelago surveys for all the breeding seabirds. This is a big undertaking; the logistics involved are complex and expensive, but the results obtained will give a much clearer understanding of the status of all our seabird populations.
If you have a moment, follow this link and take a look at the ‘Love Our Islands’ website. The short video on the webpage was filmed this summer and it captures the very essence of St Kilda in all its summer finery.
Gina, Seabird Ranger