And so they left, the guests last week at our holiday cottage, driven from their beds by the scratching, rustling and rattling, the just-discernible whine of the plug-in deterrents that don’t actually work. Not against the Shetland mouse, aka ‘da hill moose’, viking-Pict hybrid among rodents. Elvis the monster cat, who used to patrol the entire crofting township and devour the beasts, has long passed on to kitty Valhalla.

“If we’d known, we could have brought our own traps,” said a visibly upset lady, unconvinced by my “just wear earplugs” comment. “Heavens” I said, “I remember when I was camping out in the cottage when we were renovating the place, I used to wake up with them running over my face.”

They left soon after (the guests, not the mice), with a refund for the days they didn’t stay. We don’t charge extra for in-house wildlife.

It is the season of the mouse here in the Republic of Bog. Or one of them. Autumn is always a trial, as cooling weather forces the hill mice indoors, sometimes in their hundreds. Late spring and early summer brings the babies, their mothers, their extended families. I have contemplated asking a Shetland musician to come up with a tune we could use instead of the sonic repellent devices, or obversely, get some entrepreneurial fiddler to compose Pied Fiddler of Zetland rodent reels on demand and lead processions of mice over the cliffs and into the sea. Clearly, the instrumentalist would have to find a way of stopping just before the drop, or wear a jetpack. There should be grants for that.

These are special mice. The Shetland hill mouse is a variant of the more everyday field mouse (Apodemus Sylvaticus), except in the dark Satanic mills of Lerwick,  where black house mice cavort willy-nilly and prey on seagulls, sometimes killing Chihuahuas by mistake. 

The Shetland hill mouse is greyer than the average Scottish field mouse, and much harder to kill. Believe me, we’ve tried everything, from the ‘humane’ Buddhist traps that simply lead to re-infestation to the ‘redneck drowners’ (bucket and a tipping broom-handle gangway) that don’t work with waterproof swimming (crawl and breast stroke) shetland meeces. The snap traps usually hold but don’t kill, as per the illustration. That beast, sentimentally released, went off to hunt hedgehogs yesterday. And then presumably became one of the half-dozen who met a permanent end overnight.

As for bait, top five attractors: peanut butter, chocolate spread, Wensleydale, Co-op chicken dog treats, home made mutton fat soap. Or soup. I always get them mixed up.

There are various variants, in fact of moose. ‘Shetland Endemics,” they’re called. Officially identified subspecies (so far)  include the Foula field mouse (Apodemus Sylvaticus Thuleo) the Fair Isle field mouse (Apodemus Sylvaticus Fridariensis) and the Yell field mouse (Apodemus Sylvaticus Granti). All of these have adapted to small islands, but Northmavine, where we live, is across a narrow isthmus from the rest of the Shetland mainland and our mice, so far unnamed and undissected, scientifically, are undoubtedly different, stronger and more powerful than those on the rest of Shetland Mainland. Probably something to do with the Radon gas that seeps up from the red granite bedrock and which, oddly enough, rats seem unable to handle. There are no rats in Northmavine. Maybe one or two of the human variety, but on the whole they leave my cheese alone..

Maybe our mice, radiation proof as they seem to be, or indeed thriving on becquerels, could be studied for the future of the human race in the event of nuclear attack? Shetland seems set to be nuked when Putin loses his mind or patience due to the Saxa Vord missile – sorry, satellite – launch site and tracking station in the northernmost isle of Unst. However if it’s windy the Russians could well miss. Or if they want our oil and go tactical, taking out Saxa Vord would leave Unst cratered and the rest of Shetland only affected by radiation, if the wind’s in the right or wrong direction. And that  probably won’t get rid of the mice.

I watched a Chris Packham documentary once where he celebrated the idea of having house mice (those nasty black and grey things) though I doubt he’s ever had a dwelling go up in flames after the chewed wiring shorted, sparked and sent the insulation a-smoulder. In our partly 400 year old manse they have eaten wet suits (neoprene is a favourite snack) books, and especially dog treats. You haven’t lived until you’ve reached the end of a cornflakes box and found a mummified corpse and a sludge of droppings.

If all of this is putting you off booking our holiday accommodation, well, all I can say is that you’re  coming to a naturalist’s (not naturist’s) paradise. There are fire extinguishers. The family from Lower Saxony booked this coming week had the rodent situation explained and they (or at least the father) shrugged. “We’re here for the wildlife,” he said. “And we’re used to this sort of thing in Hamelin.”