For over ten years I’ve lived within a gale-flung stone’s throw of the Isle of Rum. I’ve been there many times for many reasons: to traverse Rum’s Cuillin ridge, to listen to the music and craic in the village hall and to spend nights in bothies and tents, under siege from the battering rain and wind. And this summer I returned to spend a night with the trolls.
Around 700 years ago Rum was a Viking stronghold; the mountains still bear the Norse names that they gave them: Askival (Ash Mountain), Ainshval (rocky mountain) and most intriguing of all Trallval (Hill of the Trolls). The Vikings heard strange chattering noises coming from the mountains on summer nights and attributed the eerie sounds to trolls. They even found their burrows on the summits. What is more intriguing is that the burrows are still there and the chattering and squawking of the ‘trolls’ can still be heard today.
I was fortunate to be climbing the hills shortly after the passing of a cold front. The air was clearing and scraps of cloud clung to the leeward sides of the hills as if desperate not to leave, but the fresh wind teased them apart like cotton strands. At the wide saddle of Bealach Bairc-Mheall I was over half way to the summit of Hallival, the peak that holds the most burrows of all. None of the peaks on Rum is particularly lofty and Hallival at 722 metres is one of the lowliest but its buttresses are imposing and give an illusion of grandeur. As I scrambled over the bands of rock to reach the summit I pondered on the geology of the mountain, later learning that I had been climbing over layers of igneous rock that once formed the base of a magma chamber; around the time of the dinosaurs’ demise Rum was a super-volcano. The layers of rock are alternately hard (gabbro) and soft (peridotite), formed at different times depending on the temperature of the magma.
It is these 65 million year old terra-forming processes that led to the perfect nesting habitat for the ‘trolls’ that would evolve to live here, in the softer peridotite bands. At what point they began to colonise Rum is anyone’s guess but they are still here and I was about to spend a night with them. I pitched my tent a few feet from the summit cairn. There were burrows all around me, extending along the ridge to the next peak and beyond; just below the surface of the hills thousands of tiny lives were fidgeting but outside in the glow of the sunset it was eerily calm; just a few feral goats grazed on the slopes below me. I knew the creatures would only come under the safety of full darkness to avoid predation.
It was a long wait for that darkness. On these mid-summer evenings the sun sets late in the north-west and even when it does it sets at such an oblique angle that it takes an age for it to get properly dark. The islands below me, Eigg, Canna and Skye sat in an uncharacteristically still sea, the dying sun warming the knuckles of their rugged shores. Finally, at midnight the sky above me was black and pricked with stars. An electric blue band of light hung on in the north, the perpetual summer sun of the Arctic.
I had almost given up on the ‘trolls’, having zipped myself into my tent, when I heard a ‘whooof’. Something had just flown past. I unzipped and then they came, one after another flying in, unseen, like tiny missiles: ‘Whoof! Whooof!’ I caught sight of one as it shot past that band of northern light, knife-sharp wings held tight against the night – not a troll, but a manx shearwater. Then another, and another, thousands of them landing at their burrows after a day feeding at sea. Their scientific name is Puffinus puffinus, but unlike the puffin, the shearwater is an expert flyer, built for speed. They spend most of their time in the air, like an albatross of the northern hemisphere, flying inches above the crests of waves, hence ‘shearwater’. They do not like to be on land and only do so to raise their young.
The geology, the lack of terrestrial predators on this safe island and a sea rich in sand eels has made this the breeding colony of choice for this seabird, so much so that 60,000 of them – a third of the world’s population – migrate here from the coast of South America every summer. It is the largest single island colony of manx shearwaters in the world.
There are shearwater colonies too on the islands of Skomer and Skokholm in Wales. The shearwaters on these two islands and Rum make up eighty percent of the world’s breeding population. At first I wondered what made these islands so special to the shearwaters until I learned that in centuries past there were many other island colonies around the British Isles, long since silenced by invasive predatory species such as mink and rats, brought in by us. These remaining colonies were not only precious, they were precarious too. Scottish Natural Heritage, who own and manage Rum as a National Nature Reserve, carefully monitor the birds and guard against predatory invasion.
I stayed awake for an hour listening to the cacophony. As they land they call ‘Aaak-aaak-aaaak! Aaak-aaak-aaaak!’ Not the most beautiful of bird calls but still a phenomenal chorus of thousands.
As I zipped up the flysheet and drew the drawcord on my sleeping bag I felt I was under siege by gremlins. I could understand why the Vikings attributed the noise to trolls. To be there on that dark mountain, hearing the same noise that they had heard 700 years ago made me feel like I had stepped back in time. It was the most extraordinary of hill walks.