Back to Boreray for first bird count in 20 years

To many people, St Kilda is about as remote as it gets. This archipelago, home to the largest seabird colony in the eastern Atlantic, lies 40 miles out into the ocean to the west of the Outer Hebrides, lashed by some of the fiercest storms that nature can throw at it.

The 3-hour journey from Harris in a swell-hugging motor boat is one that most would love to forget. But when our team of 7 seabird surveyors arrived on the main island of Hirta in June, our journey had only just begun.

Our goal was the outlying islands of Boreray and Soay where the majority of seabirds choose to nest. It was nearly 20 years since they had last been surveyed and, when we saw them, we understood why.

At first sight, Boreray looks completely inaccessible; rising through an impenetrable jumble of pinnacles and cliffs, to 380m, it is accurately described as awesome. We had passed it on the way to Hirta and what we saw of the landing site was not encouraging: even on a calm day, the Atlantic swell can run several metres up the sloping slab of rock whose size is belied by the scale of the island. On the advice of the boatman, Angus Campbell, we chose to land in the evening – at high tide – as the band of seaweed-covered rock that we would have to cross would be narrowest. Even so, we were glad we had brought rope-access specialists, Dan Watson and Paul Thompson, who were able to rig up a rope to help us up the first stretch.

Once onto the drier rock, we had the daunting task of lugging half a tonne of gear 150m up a 45-degree slope to the collection of ruined dry-stone buildings that offered the best chance of finding a piece of flat ground big enough to pitch a tent on. Some hope! But what a magnificent camp site it was! Perched high above the waves, and looking out westwards to the distant island of Hirta, we were dwarfed by the towering triple peak of Clesgor, home to most of Boreray’s gannets.

Towards dusk, we were surrounded by wheeling flocks of puffins, chasing each other in endless and apparently pointless circles over their nesting burrows. Later still, the island’s other residents, the nocturnal Leach’s storm petrels and Manx shearwater, announced their arrival with eerie calls in the darkness. It’s difficult to think of a more spectacular or atmospheric camp site.

This was the reason for our visit. While one can count cliff-nesting seabirds, like gannets, fulmars and guillemots from a boat, the burrow-nesting seabirds must be counted from on the ground. Puffins are relatively easy, as their burrows are easily detectable when they’re occupied by the amount of fresh digging and debris left around the entrance. But shearwaters and storm petrels are much more difficult to count: they can only be located by playing recordings of their calls and listening for their response.

We were fortunate on this trip in having Matt Wood and Zoe Deakin from Gloucester and Cardiff Universities who have experience with this technique from elsewhere. We were also fortunate to have Rowan Aitchison along as our cameraman and we were also helped by Fiona Sanderson from the RSPB, who had helped to find funds for the trip.

The trip was a partnership between the Trust, the RSPB and Gloucester and Cardiff Universities.

We stayed for 5 days on Boreray, during which time we were able to criss-cross the island, surveying all potential nesting sites. Although it looks steep, most was readily accessible on foot. On just a few locations was it necessary to call on Dan and Paul’s rope access skills.

Retiring to Hirta for a night, we revelled in the luxury of a horizontal bed and some of us even had showers. Our relaxation was short-lived because the weather remained calm and we decided to attempt a landing on Soay the next day.

Guided by Pete Moore, who was the only one of us who had landed on Soay before, having been the ranger in the 1980s, we soon found out why Soay is so rarely visited. The landing place is even more difficult than Boreray and the climb much steeper, much of the route having been carried away in a massive landslip a few years ago. We split up and spread to all corners of the island, achieving good coverage of most of the seabird colonies. The north-west end of Soay must be one of the least visited spots in the British Isles, the last survey having been from some archaeologists over 10 years ago.

Our rendezvous with the boatman later that evening showed that we were not going to get off as planned as the swell had increased too much. So we climbed back up to the relative comfort of the boulder field and bivouacked. We were glad we had because we were again regaled by thousands of puffins, shearwaters and storm petrels throughout the short night, watched over by the skeletal remains of a Wellington bomber that had crashed there in the dying days of the war. It rained overnight which made the landing place even more slippery and treacherous and necessitated the utmost caution. We took four hours to get off but achieved it safely and without incident.

Our final task was to visit the island of Dun, which forms the western arm of Village Bay. The storm petrels had last been surveyed here in 2006, and the results suggested that the population was declining rapidly, so we were particularly keen to repeat the count. We camped at the north-western end of the island and established 27 lines of sample points running up the steep slopes. We visited these over five days to see how many petrels responded to the recordings.

Analysis of the results is a complex task and it will be a while before we’re in a position to say whether the population has continued to decline. First indications are that there are still good numbers of Leach’s storm petrels nesting on the island.

Visiting St Kilda, one is always at the mercy of the weather and success is never guaranteed. Visiting the outlying islands is dependent on an even more narrow weather window and hence more unreliable. Attempting to visit all three of these islands was therefore almost impossibly ambitious within a short 3-week trip. It was a considerable relief to have achieved all of our goals and speaks volumes of the commitment of our team and the skill of the boatman.

The National Trust for Scotland works every day to protect Scotland’s national and natural treasures. From coastlines to castles, art to architecture, wildlife to wilderness, we protect all of this For the Love of Scotland.

In Our Strategy for Protecting Scotland’s Heritage 2018–23, we set out how we’re planning to work towards our vision that Scotland’s heritage is valued by everyone and protected now, and for future generations.