Here we welcome Sue Loughran, St Kilda ranger with National Trust for Scotland to tell us about biosecurity ‘From the edge of the world’.
In the last few weeks we have been working with Sarah Lawrence (Biosecurity for Life Project Officer) to improve our measures for the islands of St Kilda, but what does “biosecurity” actually mean? How do we carry it out? How can everybody play their part?
One of the major threats to our islands is the possibility of an invasion of “non-native” species (most notably for St Kilda, this would be the accidental introduction of the brown rat). As one of the most important sites in the north Atlantic for breeding seabirds, this would be catastrophic for the nesting birds, and so we need to keep a vigilant watch for any signs of rats coming ashore and work very quickly if we have evidence of their presence.
Sarah is very familiar with St Kilda (she was Seabird and Marine Ranger here in 2019) and she came laden with information for us to give to visiting yachts, key information on how to set up a network of baited stations and all the necessary ingredients to make tasty wax bait.
The first part of the response is to have a permanent set of baited boxes situated around the islands. The bait is harmless, and is a mixture of wax and strong flavouring such as chocolate or coconut. It is designed to be attractive to rodents, who will nibble on it harmlessly; leaving their tell-tale chew marks behind. We set up a network of 12 such stations around Village Bay and a further 14 around the rest of Hirta.
We spent a few long and very enjoyable days hiking around the island setting up and marking the stations with GPS. We now have to check the village stations every week, look for chew marks, smooth back or replace the blocks and record what we find. The rest of the stations will be checked monthly. All of this data is then recorded and sent back to the Biosecurity for Life project, who have a support team available, should there be positive sightings.
Our job is complicated by the fact that we have a large population of endemic St Kilda mice, and so skill is needed in identifying which species made the chew marks.
If rat chew marks are detected, a large and immediate response is triggered, aimed at eradication as quickly as possible.
The wider plan is to extend the range of these stations to include the other islands within the St Kilda archipelago later this year.
Just as important as carrying out surveillance, is the process of active prevention. The Biosecurity for Life project is working on small islands around the British Isles, and aims to educate the public in the importance of preventing the spread of invasive mammals. Their leaflets give practical advice to travellers about care when packing and checking for signs of rodents in their luggage. Here on St Kilda, we try to give this information to as many visiting yachts people as possible. We also require all passengers to approach the jetty by “open tender” (a boat without an enclosed cabin), as there is less likelihood that a rat could be unwittingly brought ashore.
The visiting landing craft, which brings supplies to the Qinetiq base on the island several times a year, has to undergo stringent checks prior to and whilst sailing to St Kilda. A dedicated watch person observes the slipway whilst the vessel is loading and unloading, and the whole process is also filmed to check for rodents.
In addition to mammalian biosecurity, we are also working hard to prevent the spread of non-native pathogens between islands. All visitors are asked to walk over a foot-mat impregnated with disinfectant when they arrive and leave. This aims to prevent the spread of bacteria, fungi, spores and viruses and forms a further facet to our biosecurity plan.
Biosecurity for Life is a partnership project between RSPB, National Trust for Scotland and the National Trust, and is funded by EU Life.
We’re really trying to keep the islands safe and hope that you will help us whenever you visit. We look forward to welcoming you in as bio-secure a way as possible!