Imagine you’re a farmhand living about a century or so back. The last of the summer warmth is just eking through to the end of September. Your back is aching and your limbs sweating as you carry bundles of wheat into the barns and start arranging them in ricks.
With your mate out in the field gone off to fetch something from the farmyard, you take the opportunity to have a quick break, and rest your stiff body back against one of the ricks. Just as you start to relax in the cool shade of the barn (with all the dust in your nostrils blocking the smell), suddenly the wheat-mattress beneath you starts to move! You jump back in alarm, and looking back at your former rest-spot you realise it is absolutely teeming with tiny, sandy-coloured mice, frolicking through the rick where their nests remained hidden within.
This would’ve been a common sight in the farming life of rural Britain for centuries; long before Hampshire naturalist Gilbert White scientifically described harvest mice for the first time in the 1790s.
The name ‘harvest mouse’ easily conjures up the image of the animal tumbling and snuffling its way through ears of wheat and barley. Something that’s been asked to me on occasion therefore is whether I go looking for these animals in the crop; yet today you’d be very lucky indeed to find these animals in the centre of farming activity. So just why is that the case?
Before the advent of agriculture, these animals would’ve likely been most abundant in the floodplain marshes that proliferated on major river systems. While many of these would’ve been drained over time (and harvest mice can still be found in surviving or restored wetlands), the new farmland that was created provided a very suitable alternative. And when that crop was bought inside, the harvest mice revealed themselves in huge numbers. Farm buildings would’ve also been handy winter refuges, and there’s even record of harvest mice taking up residence in meat curing sheds where they earned the moniker of ‘bacon mice’!
So what went wrong? You might have guessed it, but it’s simply down to the fact we changed the way we farmed. Harvest was moved to much earlier in the year, often when the mice were still at the peak of their breeding season. Crops were sown mechanically in ordered lines, with each plant much further apart, leaving few dense clumps suitable for nest building. On top of all that, this new dawn of the combine harvester resulted in mowing from the edges going in rather than out from the centre, giving harvest mice no chance of escape.
Post-war intensification of agriculture resulted in so much of our wildlife declining, and it appears likely that the same happened to the harvest mouse – or at least it had to adjust the way it lived alongside us. Nowadays, it’s the patches of rough grass left to go wild, the margins of fields and the roadside verges, the reedbeds and marshes, where harvest mice can still tease out a living.
The question is, how many of these ‘messy spots’ still harbour the animals? Does the isolated nature of many of these areas, or perhaps poor connectivity between them, have an impact on how well harvest mice are doing? The answer is that we don’t know, simply due to so few people looking. This is exactly what we are trying to rectify here in Devon.
Unless there are significant changes in farming policy, it seems unlikely harvest mice will ever be as abundant within the crop again. But the crucial link between this animal and rural communities can still be maintained if we are willing to maintain these slightly wilder corners of the landscape, and in some cases make small changes to the way it’s managed – just cutting the verge a bit later in the Autumn can make all the difference. So while the harvest mouse may no longer strictly be part of the harvest, there’s no reason it can’t remain a familiar denizen of the countryside.
To sign up as a harvest mouse nest searcher, send us an e-mail at firstname.lastname@example.org. You can also donate to our project to help us extend our work throughout the winter by providing a donation at https://www.justgiving.com/campaigns/charity/devonmammalgroup/harvestmouse.