waste of energy and food if they couldn’t. But undoubtedly some nuts survive to germinate and grow a hazel tree and the squirrels must be saluted for fulfilling that important, if accidental, ecological role. I am glad I saw them building that drey and I noticed that, whether by chance or design (surely design), it was built on the sheltered side of the trunk, away from the prevailing wind. Squirrels don’t hibernate, so I find it a comforting thought that when the bitter winds slice through in the long December nights they will be in there, tucked up in their long fluffy tails, curled as tightly as a barrister’s wig.
This moment in the year is also marked by the very sensible migration indoors of wood mice, Apodemus sylvaticus. Voles and shrews are fascinating, but wood mice are classy. Hamster-golden with huge ears and big glossy eyes as black as polished ebony, underbellies as white as the rose of York, and their extravagantly long tail (they used to be called long-tailed field mice) pursues them, never touching the ground, flowing with all the elegance and style of Elizabethan calligraphy. They skip across the ground with the grace of a gazelle, barely seeming to touch the surface, and they can climb and leap like a trapeze artist. I’m entranced by their speed. I have always admired them and, unlike Lucy when she’s in hyper-efficient housekeeper mode, I am overcome by a downward somersault of the spirit when called upon to trap them. The notion of poison has always been abhorrent to me – out of the question.
There are times when I have had to set my natural-history instincts aside and give in to lobbying from household and family. After all is said and done, they are mice – beautiful mice – but with all the mouse potential for causing trouble. If they do become a nuisance and I am harried into taking action, I use Longworth live traps and transport the captives a few miles up the glen before releasing them, wishing them well and apologising as they go.
At first I made the mistake of thinking that releasing them in the garden was good enough until one day I caught one with the tip missing from his tail. The very next day he was back in the trap in my daughter Hermione’s bedroom. I was pretty sure it was the same mouse so I took him much further away, about three hundred yards. Two days later he was back in the trap. To be certain I now marked his back with a touch of nail varnish between the shoulder blades where I reckoned he couldn’t groom it away. I took him to the village a quarter of a mile to the east and furtively released him into someone else’s garden. This time it took a week, but back he came, straight into the trap, proudly showing off his tell-tale smudge of oyster-shell pink. I was left scratching my head, pondering the mysteries of animal behaviour. Just how does a mouse, two inches high and six inches long, find its way over a quarter of a mile of what, presumably, must have been entirely strange and hostile territory? Is it scent? (We know that a male moth can detect a female’s pheromones up to a mile away.) Or is it some electro-magnetic homing compass we don’t properly understand? It seems entirely logical that any foraging species with static young in a nest must be able to find its way back over distances appropriate to that species. But a quarter of a mile? That seems absurdly adventurous for even the most ambitious mouse foray. And yet I know very well that I shouldn’t allow myself to be surprised by this amateur circumstantial evidence of my own concocting.
Lucy once had a Labrador dog that was accidentally left behind at a friend’s house some ten miles in a straight line from home. But those ten miles included crossing the Beauly Firth, a tidal estuary more than two miles wide, or a circumnavigation round the end of the Firth, increasing the journey to more than twenty miles. Frantic searches in the vicinity of the friend’s house revealed nothing, but twelve hours later the old dog turned up at its own back door, wagging its tail. It was remarkable enough that he knew his way home, but that his homing instinct had caused him to swim across open sea or had taken him many miles in the wrong direction if he had gone round also seems to indicate some powerful impetus at work. I marvel at animal behaviour but it never surprises me. Nature has had a long time to hone its secret skills.
Throughout the spring and summer, these engaging little mice are more than happy to live in the woods and fields where they belong, and are one of several small mammal prey species upon which so much of our wildlife depends. Tawny and barn owls, foxes, badgers, wildcats, pine martens, stoats and weasels, buzzards and kestrels, even herons, crows and brown rats all eat wood mice when they can. With bank and field voles, they are the staple diet of our owls. Without them the owls would perish and disappear altogether. But the wood mice are hard-wired to find a warm, dry place to nest for the long cold months. We have generously provided them with an endless selection of choices: garden sheds, byres, stables, garages but, best of all, centrally heated houses, often with a fast food supply readily tipped in for good measure.
In this old house (some bits are eighteenth-century and earlier) the thick outer walls are of large round whinstones of hard metamorphic schist gathered from the fields and burn beds, heaved and levered into position by men with aching shoulders and rough hands, whose craftsmanship was passed down from generation to generation. However skilfully the Gaelic-speaking Highland masons placed these stones to create a handsome vertical wall on the outside, there were always hollows and gaps in the interstices that had to be packed with lime mortar to hold everything together. Inside the walls, which were always two or more large stones thick (up to twenty inches), there were spacious cavities loosely filled with end-of-working-day lime tossed in, along with any handy rubble. (While plumbing in new heating I once found a George I halfpenny dated 1718 in one of the walls – I’d treble your money for your story, Mr Highland Stone Mason, if only I could.) Lime mortar doesn’t clench in a rigid chisel-resistant grip, like cement: it sets yet remains friable and crumbly, like damp Demerara sugar. Any diligent mouse can scrubble away at the weaknesses and burrow through.
Once inside the thick old walls, the mice enjoy a labyrinth all their own. They can go where they please. They travel through the hollows, up, down or sideways, as safe and secure as any city metro system. Modern insulation makes perfect bedding for a wood mouse – warmth and comfort laid on. At night I lie awake and hear them scuttling back and forth in the roof, up and down the ancient plaster and lath walls and occasionally popping up inside rooms. From time to time I see them nipping out from under the kitchen units to sample left-over meal in the Jack Russell terriers’ bowls – a source of constant frustration to the dogs, which charge, skidding across the vinyl, to crash land among the bowls, always far too late.
We are lucky: our neck of the Highland woods does not have the very destructive and invasive house mouse, Mus domesticus, originally an alien species from Asia, trans-located all round the world by man, and the progenitor of all pet and laboratory mice, which can carry unpleasant diseases such as leptospirosis, typhus and meningitis – even bubonic plague. They are present in the Highlands, but mainly restricted to the grain-growing areas of the east coast and to towns and cities such as Inverness. Happily, they don’t venture up the glens. House mice will gnaw through just about anything: lead and copper pipes, electrical cables, plastic, woodwork, plaster, skirting-boards and structural joists, even limestone.
Our wood mice, alas, are not entirely blameless: they delight in shredding polystyrene pipe insulation, and if they elect to nest in a wardrobe of stored clothes their actions can be very distressing. By comparison with house mice, though, the damage they do is slight. They are very clean living and are not known to transmit disease. When I find their nests in the woods, exquisitely crafted balls of grass, moss and leaves, often lined with sheep’s wool, there is virtually no smell.
Years ago I brought some reindeer skins back from an expedition to Lapland. I thought they would make cosy bedside rugs for our growing family, but I was wrong. Reindeer fur has a fine woolly undercoat but the outer fur consists of longer, hollow, air-filled hairs for efficient insulation in an Arctic climate. These hairs are brittle. The regular passage of children’s little feet broke the outer fur into a constant fall-out of shards, which stuck to everything, itched in their socks, clogged the vacuum-cleaner and drove their mother to drink. The pelts were banished to a cupboard in the cellar, securely contained (we thought) in sealed polythene bags.
The wood mice said, ‘Thank you very much.’ It took them no time at all to find the bags, nibble
