Cnocan Sìthean (Fairy Hillocks) – or simply Sìthean – is the Gaelic for the little mounds of sphagnum moss that grow up through clumps of grass. It’s a symbiotic relationship, the grass (usually deer grass) providing shelter and support for the moss, the sphagnum a reservoir of moisture for the grass in dry weather. If left undisturbed, they can grow up to two feet or more high, but a foot or so is more typical. They are extremely common on the nutrient-poor, acid soils over gneiss, especially if only lightly or occasionally grazed by sheep.
As our croft has been progressively enclosed, and more systematically grazed, the Sìthean have become fewer, and are now found only in Bothy Field and High Field. As it’s the last field before the common grazing, we hope to keep High Field as natural as possible – and that means keeping as many Sìthean as practicable.
Trekking up to the common grazing and back each morning, I must carefully pick a path between the many Sìthean, slowing me down, and occasionally tripping me up. Face down in the wet vegetation, and utterly deserted by my sense of humour. So you’d think I’d be glad to leave the sheep to trample the Sìthean into non-existence. Wouldn’t you?
But, then, you might change your mind if you’d met this little fellow – a field vole, or Famhalan in Scottish Gaelic.
As I weave my way amongst the Sìthean I see countless little rapid streaks of grey-brown, as voles (and some field-mice) scurry from their foraging into the cover of the nearest Sìthean. Kneeling down to examine the hillocks in detail, it’s apparent that each has one or more neat little vole-sized entrances, and many have a little hole in the top as well. Earliere this summer I marked a handful of Sìthean of varied size and shape, to keep an eye on as I passed them each day.
One interesting change I noticed was that, in poor weather, some ventilation holes had clearly been stuffed with neat little bundles of dried grasses – and these were then removed again when fine weather returned.
One day, purely by chance, I came across a Sìthean of which the top had been torn off (I was loathe to do such a thing myself – sacrificing the shelter of a harmless defenceless creature for the sake of my shallow curiosity). I was delighted to find that what remained were the entrances, passages and chambers of the Sìthean . It’s just a pity that, the top having been removed, I couldn’t see how the ventilation hole would have positioned relative to this layout.
I’ve recently been reading a fascinating book on the archaeology of Uist, with a couple of chapters dedicated to the iron age dwellings known as Aisled Houses and Wheel Houses (both circular in plan), of which there are numerous known examples in Uist, though not as numerous, as technically advanced – or now as well preserved as in Orkney. There are aspects of these dwellings that remain mysterious even to the archaeologists – in particular the purpose of the perimeter ‘corridor’ of the Aisled House, and how the roof was formed, and whether it was open to the sky above the central fireplace. I think the archaeologists might do well to consider the building technique of the humble field vole: I have no doubt it would be as interesting and as instructive as it would have been to our forebears of the Iron Age.