Welcome to the ninth instalment of our work on the Shiant Isles Recovery Project. Here Jack Ibbotson, Molly Heal, and Johnny Tayton give us a glimpse of life on the islands while undertaking survey work for the project. 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.
Shiants episode 9: From winter to summer
The 2017 research monitoring team with boat operators. From left: Boatman Johannes Engebretsen, Summer field team Jack Ibbotson, Molly Heal, Johnny Tayton, and boatman Charles Engebretsen.
During the winter eradication phase our main tasks revolved firstly around deploying and monitoring rat bait stations, and then spending months carefully monitoring the state of non-toxic wax blocks. Our main challenges were the short days and the unsettled weather. The winter was dominated by Atlantic storms, enough to shake the earthy and substantial walls of the small bothy on Eilean an Tighe. The island’s owners had allowed us to use the small bothy as accommodation during the project… we needed it! All too frequently the VHF would crackle, ‘The Minch – North Easterly force 8 increasing storm force 9 later, sea state very rough, persistent wintery showers’.
Despite the hardships of the winter all three of us jumped at the chance to return to the Shiants when offered positions on the RSPB research team for summer 2017. We returned to set up camp on the Shiants at the end of April, relying partly on the bothy but mainly on the satellite cabin/tent set up just a short distance behind it. An unusually unsettled spell of weather engulfed the islands during our first week with snow briefly settling on the east slopes of Garbh Eilean, something we experienced only once during the winter. Thankfully conditions quickly improved and the VHF averaged an altogether more manageable, ‘Southerly force 3-4, sea state slight to moderate’.
The speed at which spring began on the islands was staggering. Through May the colours quickly changed from pale yellow to a flourishing dark and luscious green. Thrift or sea pinks adorned the rocky shores and crags, contrasting sharply with the vibrant yellows of the lichens in the splash zone. Our first tasks involved monitoring vegetation quadrats and collecting pitfall traps of crawling invertebrates. Both are likely to have been previously impacted by the rats and we are keen to try and understand what changes might have begun since the end of the eradication.
Molly and Johnny with a vegetation quadrat. Photo: Jack Ibbotson
By June the majority of the seabirds were settled incubating eggs and many land birds and waders were busy feeding young and fledglings. By this stage our monitoring had turned to the bird life of the islands and the long days were dominated by monitoring the contents of carefully selected nests in our study plots.
The aim with the pre- and post-eradication ecosystem monitoring is to try and explain the impact that the rat eradication has had in terms of seabird fledging success, presence of land birds, vegetation cover and invertebrate populations. It will be a number of years before it is clear what the long term changes have been. So far, seabird productivity has not changed wildly at all of our study sites, although there appear to be modest rises in most cases. In some areas, colonies have may have expanded. For example, we seem to be finding many more nests at the northern end of the Boulderfield, Carbnach Mor than had been seen before 2016 (the first post-eradication year). Activity of some seabird species at the islands has risen noticeably such as the total number of great skua nests found on the largest islands – Eilean an Tighe and Garbh Eilean has doubled from 2015 to 2017. However, it must be remembered that there are many factors affecting seabirds. Add in the pressure on food resources, climate change and pollution to predation including from rats, and it is a truly huge task to try and disentangle what is happening out there.
Seabirds in the boulderfield at Carnach Mor, Garbh Eilean. Photo: Jack Ibbotson
Another research assistant is now working on the sorting and identification of three years of pitfall trap samples. In total, 980 invertebrate samples were collected – covering one field season before and two years following the eradication on the two largest islands, Eilean an Tighe and Garbh Eilean. It will probably be the largest arthropod dataset ever produced on the Shiants – fantastic news for the project.
As you may have been able to tell we’ve all thoroughly enjoyed our time on this amazing cluster of islands! It’s been great to be able to be here in all weathers studying the wildlife that makes its home out in the Minch; we look forward to seeing how the data we collected helps us know more about the nature here and what part it plays in the next chapter for the Shiant Isles.
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 being led by Wildlife Management International with the support of Engebrets and Sea Harris Ltd.