Shiants episode eight: Buzzing about biosecurity

Welcome to the latest instalment of our work on the Shiant Isles Recovery Project from Laura Bambini, RSPB Scotland's seabird recovery officer. The project is an initiative to remove non-native black rats from the isles in order to provide safe breeding sites for Scotland’s globally important seabird colonies. It is part funded by the EU LIFE+ programme and is a partnership between RSPB Scotland, Scottish Natural Heritage (SNH) and the Nicolson family, who have been the custodians of the Shiant Isles for three generations.

In the last installement Iain Maclean, a research assistant in the project, reflected on his time spent on the island. Here Laura gives us an update on the biosecurity work that’s been taking place and will be crucial to the long term success of the project.

One year on from the end of the operation to eradicate the black rat on the Shiant Isles, our team continues to monitor for signs of any surviving rats on the islands. Following international best practice, we’ll have to wait a full two years from the last sign of rat before we can declare the islands rat-free. In the meantime, we’re focussing our efforts on preventing a new population of rats arriving and establishing on the Shiant Isles – it’s all about biosecurity these days!

Our project manager, Charlie, and RSPB Scotland’s conservation officer in Western Isles, Robin, visited the islands a couple of times over the winter months to check the permanent rat monitoring stations for signs of them. We’ve placed a few dozen Protecta bait stations around the islands, and each station contains cocoa- or peanut butter flavoured wax blocks which rats love to chew. If a lone rat arrived on the islands in the dead of winter, it would be keen to find a dry and warm place to shelter in so we  placed a few ‘rodent motels’ in strategic locations around the islands. These motels are plywood boxes that contain bedding material, and more wax for the rats to chew on. The winter checks found no sign of rats, which was great news.

One of the rodent motels

In order to keep the Shiants rat-free for the years to come, we want to raise awareness about the need for rodent biosecurity in the Western Isles, and amongst managers of other seabird islands around the UK. Effective rodent biosecurity is like a three-legged stool, where each of the legs has an important function without which the stool wouldn’t stay upright. The legs of the biosecurity stool are: prevention, early detection and rapid response. Our team on the Shiants is working on ensuring the second and very important aspect of biosecurity is in place (early detection). Last December, we trained up a group of keen volunteers to act as the Shiant Isles Rapid Response Team (SHIRT) who are ready to spring into action if our team on the islands detected signs of rats.

This summer, we are working on the final important leg of the biosecurity stool: prevention. To do this, we recently held the first of four biosecurity training courses aimed at island managers and other people who have a key role to play in ensuring the ‘incursion pathways’ to the Shiants and other offshore islands are kept secure and rodent-free. The training course in Leverburgh on the island of Harris was attended by a hardy bunch of islanders who were keen to learn about rat eradications and preventing new incursions on islands. 

Taking the course out of the classroom and into the outdoors

The course participants learned about the different tools available to detect rats on islands, and about the ways and means rats have for reaching offshore islands. We were reminded of the long history of shipwrecks along the coasts and islands of the British Isles – and there have been a staggering number of wrecks over the centuries – and that these are by no means a thing of the past. Just a few years ago, the trawler Spinningdale ploughed into Hirta, the main island in the St Kilda group. Thanks to effective biosecurity measures and protocols in place, the National Trust for Scotland was able to respond and make sure no rats abandoned the wreck for safety on the island. The St. Kilda islands are home to a vast number of breeding puffins and other seabirds, including the largest colony of Leach’s storm petrels on this side of the Atlantic which would have been at risk from the rats. The Spinningdale story served as a reminder that vigilance is needed to keep our seabird islands safe and free from rats, and that similar events could happen anywhere in the Western Isles or on any of the dozens of important offshore seabird islands in the UK waters.

Field training on Boreray

Following on from a day in the classroom, the next day we took a boat to the island of Boreray in North Uist, to look for rat sign and to gain practical experience in deploying rat detection tools. Walking round the island on the sunny and calm day, it was easy to see how rats could reach offshore islands – Berneray island appeared just a stone’s throw away. Several ruined buildings and ancient stone walls on the island could feasibly host large numbers of breeding European storm petrels. Alas, none are present on Boreray now. Instead, we found several rat burrows and runs. The storm petrel, the UK’s smallest seabird, is defenceless against rats that are as big as the adult birds, and so storm petrels are only found breeding on rat-free islands. 

The course on the beach at Boreray

Talking to course participants from different islands in the Western Isles, we all agreed on the importance of biosecurity and the fact that prevention is better than the cure. I hope that the course, and the others that will follow, helped to inspire island managers and boat operators to work together to keep seabird islands rat-free. I certainly came away thinking the Shiants really are a special place and how important it is to keep them rat-free for the years to come. By doing that, the storm petrels will hopefully find them a safe place to breed, and establish on the islands.  

The Shiant Isles Recovery Project is a partnership between RSPB Scotland, Scottish Natural Heritage and the Nicolson Family, it is funded by EU LIFE+ Nature [LIFE13 NAT/UK/000209 – LIFE Shiants] and private donations. The eradication is led by Wildlife Management International with the support of Engebrets and Sea Harris Ltd.