In this blog our Biosecurity Officer Sarah recounts a long and tiring day to the Flannan Isles to set up rodent surveillance and count the seabirds.
While Tom was waking up to his first morning on North Rona, I was in a RIB, skimming due west across the North Atlantic away from Great Bernera off the west coast of Lewis at great speed. Tom and I had planned to travel together, but after ten days holed up in a cottage on the Isle of Lewis patiently refreshing the weather forecast, it became clear that we needed to seize our short weather window and split up to cover more ground.
My destination would be the Flannan Isles, for a “long day trip” since the swell was due to pick up and risked us getting stuck on the islands if we stayed overnight. The Flannans are also known as the Seven Hunters, or Seven Haley (Holy) Isles – both descriptions are understandable since the perilous shoreline has long been feared by sailors, and the islands are believed to be inhabited by spirits, which has led to a number of customs expected to be followed by those landing - for instance "it was forbidden to kill a bird after evening prayers" (we should manage that one!).
So at 04:30am on the 19th June, I boarded the RIB at Kirkibost Pier alongside the MarPAMM Seabirds Count team and Robin Reid from RSPB. I was equipped with a drysuit for what I expected to be a splashy 30 kilometre journey through residual swell to reach the Flannans. Soon we were speeding away from Lewis with the sun rising behind us and the sea calming ahead… For an hour or so we passed several pods of dolphins gliding in and out of the flat calm water before a lone Leach’s petrel reminded us of our destination and I looked ahead to see the lumpy silhouette of the Seven Hunters appearing on the horizon.
By 7am we had arrived and began assessing our options for landing. Landing at the Flannan Isles is notoriously challenging: the islands are not especially tall (highest point 88m), but they are surrounded by cliffs on all sides, and the swell often makes it impossible to find a landing spot calm enough to jump ashore onto the rocks. The largest island, Eilean Mòr, has two landing places with concrete platforms built when the lighthouse was installed in 1899. Neither landing place has been maintained for many years – and the west landing now appears to be a particularly interesting option, with several steps and platforms seemingly missing altogether… The east looked much preferable, with all steps present and correct, and even a sturdy-looking ladder (although the morning’s low spring tide meant it was out of reach). To my relief, there was very little swell at the east landing, so the day’s equipment was loaded into the tender and carefully hoicked onto the rocks and up onto the landing platform.
With the equipment ashore, there was space to move more freely around the boat – allowing us to begin the day’s first job: counting the cliff-nesting seabirds. We began two miles west of the main island at Roaiream, host to the Flannan Isles’ gannet colony. Here Robin briefly jumped ashore and set up the first biosecurity surveillance station for the Flannans. We worked our way around the coast of Roaiream followed by Eilean a’ Ghobha, with each member of the team counting a different seabird species. I was tasked with the guillemots – many of which were dotted through the middle of the gannet colony, and others tightly packed on their customary rowdy, narrow ledges. When we’d finished it was 10:00am, and we were pleased to have one of the three “island groups” that comprise the Flannans counted.
We returned two miles east to the smallest of the three groups, comprising of the islands Soraigh, Sgeir Toman, and Sgeir Righinn. The contrast to the stark cliffs of Roaiream and Eilean a’ Ghobha was immediately apparent. There were no gannets on these small low-lying islands, and the cliffs quickly knitted into steep, tussocky slopes with thrift glowing pink in the sunshine. These islands were the realm of puffins and fulmar, so I took a momentary respite from my guillemot counting duties and chanced a tea break. It wasn’t long before we reached the narrow geo between the islands and found it teaming with auks and kittiwakes – guillemot duties resumed – and by 11:30am we had completed five of the Seven Hunters, with only(!) the two large islands to go.
Half a mile north and we were back to where we had left our bags on Eilean Mòr. First we would count its neighbouring island, Eilean Tighe, and decided to speed things up by splitting the team; myself and Robin would land on Eilean Tighe while the others counted the cliff nesting birds from the boat. Now to find a landing spot! We were told there’s a known landing place in a geo on the west of the island – this would require an extremely steep climb into the dark, damp geo and the swell was not in our favour. The south east looked much better, and in light swell we managed to jump ashore into a gap between two large rocks and climb to the top of the island. Wow! We were greeted by carpets of sea thrift, shags and razorbills nesting behind every suitable rock, and a stunning view across to the lighthouse on Eilean Mòr. But there was no time to take in the view, so I set to work scouting out suitable locations for biosecurity surveillance stations. One of the sites I had planned from studying maps was not going to work: the bothy at the far east of the island was full of nesting shags and razorbills that would be disturbed if I went near, so I found other linear features that may be appealing through-routes to an arriving rodent. With five surveillance stations set up, we returned to the boat.
Now we had Eilean Mòr left to count. It was 12:30pm, and the combination of the 04:00am start with what was turning out to be a blisteringly hot calm day (by Hebridean standards), meant we were wilting. A top-up of sun cream, dry suits shed, and we were off for the last leg of the cliff counts. Eilean Mòr had a bit of everything, rolling slopes of fulmar, geos full of kittiwakes and guillemots, nooks of razorbills and shags in every corner. Just when we thought we had seen it all – we turned back towards the jetty and there was the call, “eagle!” …Well that woke us up! Sure enough, perching at the top of Eilean Mòr was an adult white-tailed eagle, and soon a second appeared overhead! After a good ten minutes admiring this surprise finding, it was time to land.
The tide had risen enough for us to reach the ladder, so one by one we climbed ashore, and made our way up the narrow staircase built into the cliff face. Eventually the stairs turned into a steep, paved track; the remains of the railway which had led from the lighthouse down to each landing place. The old steam powered bogie would have been a welcome sight as we carried our bags up the hill had it not been removed in the 1960s. We stopped at Charing Cross (as the junction between the east and west landings was affectionately known by the lighthouse keepers) for a late lunch and to plan for our next task. It was here I remembered the old customs visitors were supposed to follow. “On reaching the plateau it was essential to take one’s hat off and make a deiseil – a sunwise turn – giving thanks to God”. I’m sure the whole group succeeded in this tradition if only by way of an awed reaction to finally making land on the Flannan Isles, and discovering such a perfect warm, sunny afternoon on the plateau.
It was 3:00pm now, and the final seabird counting task of the day was to complete a puffin census. Because they nest in burrows, puffins can be rather tricky to count accurately – especially when their colonies are on inaccessibly steep slopes. Many of Eilean Mòr’s puffin burrows are accessible from land, and the survey method used there is a random sample – so luckily we didn’t need to count every single puffin! Instead, we found pre-existing points, where we counted all the “active” puffin burrows within a 2.5 metre radius. We used a bamboo cane with a rope to calculate the survey circle, and only counted burrows with active signs including puffin droppings, feathers, hatched eggshells, fresh digging, or dropped fish – being careful not to include burrows belonging to the resident (invasive non-native) rabbits, introduced by the lighthouse keepers.
The puffin survey took several hours, until it was time for me to venture off and install biosecurity surveillance. I explored the perimeter of the island, scouting out suitable and sheltered places for a surveillance station. Arrival points: one box near each of the landing places and the helipad; sources of food and shelter: the Lighthouse Compound, and nearby the Clan McPhail bothies; linear features (rodent highways): Charing Cross, and alongside the old walls. I made sure the boxes were spaced out across the whole island – a rodent can move quickly, and a rat could hold a territory of just one hectare, so may never encounter a surveillance station on the other side of the island.
I checked my watch... 8:40pm! The boat was collecting us at 9pm, and I could see that the others had already made their way back down the steps. In the rush of the day, there hadn’t really been time to stop and reflect on having landed on these islands I’d read so much about – or what a success it was to have biosecurity set up on the island with one of the most difficult landings. The sun was going down quickly now, illuminating the thrift… I began my descent back to the east landing, where hundreds of puffins had now congregated for the evening along the edge of the railway track… Reluctantly I left them behind and continued down to the jetty. Drysuits on, we clambered back into the boat for our almost two-hour journey into the dusk. Twenty hours after we started, we were back on Lewis – a “long day trip” indeed – but what a day!
Having biosecurity set up on the Atlantic outlier islands is a fantastic start – and we hope to revisit North Rona, Sula Sgeir, and the Flannan Isles for a first check of the stations in July 2021. Routine checks of these surveillance stations will be required long-term (in perpetuity!), as the threat posed by invasive non-native predators such as rats will continue to be a concern to breeding seabird populations forever. We’re keen to build a network of “regular” visitors to these islands, who may be willing to check the harmless wax blocks inside surveillance stations for signs of chew marks. If you have come across this blog in anticipation of a future trip to the Flannan Isles – and you may be able to make a quick check of some surveillance stations while you’re passing – please get in touch and we can send you some instructions.