What was that? A tiny flash of russet, nearly under my feet, just vanished into the long grass. Far too small for a stoat or weasel. Surely too auburn for a mouse. What then? “A harvest mouse,” Dad confidently tells me when I phone. “Have a look in the undergrowth for nests.” I glance in the straggly grass, but it’s time to leave for the school pick-up.
Once home, I find out it’s the ideal time of year to survey harvest mice. The data is vital as Micromys minutus is on the red list for Britain’s mammals, and the last widespread study was in 2013-14, so the Mammal Society has recently launched a new national survey.
It’s the UK’s smallest mouse, measuring about 5-8cm from nose to tail base, and weighing about the same as a teaspoonful of sugar (and twice as sweet). Surveying doesn’t require finding these micro mice – I was lucky to glimpse one – but rather recording their nests. Over winter, the larger breeding nests are abandoned, and the smaller shelter nests are unoccupied as the mice prefer hedgerows and tussocks, so there is low risk of disturbance.
After contacting the Mammal Society, I return on a bright afternoon, clutching a notepad and feeling official. A kestrel hovers over the rough grassland – a promising sign, but as I wade into the long vegetation, it seems like an impossible task. Nevertheless, I begin, dividing sections of tall grass with a stick. It takes patience, but I get my eye in. Elated, I find a nest, followed by another in quick succession.
Each nest is a tangle of woven grass, smaller than a tennis ball, hanging from the surrounding vegetation. It takes balance and skill to make. The mouse uses its prehensile tail and back legs to grip the plant, freeing its front paws to grasp the leaves. It splits them lengthways with its teeth, keeping them attached to the stem, then weaves them together. Now the nest is brown and old, and I can see the tiny entrance hole – just the size for my little finger.
The light is fading and the grasses merge and blur. I’m sure there are more nests, but I stop. I’ll await the results of the wider survey with interest, but at High Ash Farm the harvest mouse endures.
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