This weekend we joined up with Wiltshire Mammal Group to undertake a Harvest mouse survey on the byway from the B4192 up to Sugar Hill. The sun shone and it felt almost warm as we divided tussocks and parted grassy clumps along the edge of the track searching for the tennis-ball shaped and beautifully woven treasures of harvest mice summer nests. They are typically around 30cm above the ground, woven firmly among vertical stems with an obvious entrance hole. Adult females build several nests in a season from fresh green grass ensuring they are well camouflaged. However, by autumn (when they are no longer in use) they are easier to spot as the vegetation around them dies back. In winter, harvest mice retreat to the ground level.
Due to changes in farming practice and habitat loss it is thought that harvest mice populations are in decline, however the Mammal Society’s 2018 ‘Review of the population and conservation status of British mammals’ highlighted that very little is known about our populations (They are classified as Near Threatened by the IUCN). The Mammal Society divide the country into 2km by 2km grid squares and record presence of harvest mice nests within these squares. Within Aldbourne parish their map show a couple of sightings from 20-40 years ago. However, that all changed this year starting with a survey training day at Ramsbury Brewery run by Gareth Harris (Wiltshire mammal group) at the end of October. Encouraged by the success of that event we set out to fill in the many gaps in the grid in our local area. I’ll just say dog walks have taken a bit longer recently as we’ve stopped to poke around in long grass and at the base of hedgerows! The thrill of finding a nest is amazing and often leads to one thinking I’ll just have a look in the next grass clump….and the next.
We’re excited to report that we have found harvest mice nests in every square in the parish this autumn (apart from a couple which only dip into the parish). It’s great to know they are living right across our local area but of course this doesn’t tell us about population sizes or dynamics.
We have collected over 20 harvest mouse nests so if you would like to come and see one in the flesh then let us know, we would also be happy to go out looking with anyone who wanted to check out their local arable margins for nests. When things return to normal we hope to take these nests into the school so that the children can have the opportunity to touch and hold them.
If you’re lucky enough to spot a harvest mouse nest while out and about please log the
sighting on the Mammal Society’s brilliant Mammal Mapper App which is free and designed to record mammal sightings in the UK which are then used for scientific research and conservation.