A previously unrecorded species, the tiny harvest mouse, has been found by Action for the River Kennet (ARK) volunteers at Stonebridge Wild River Reserve, Marlborough.
The ARK volunteers discovered Europe’s smallest mouse at the reserve whilst carrying out a conservation task. This brings the total number of mammal species recorded at the wildlife site to 21.
Last Saturday ARK invited Gareth Harris (county Mammal Recorder) and Wiltshire Mammal Group to the reserve. Gareth trained ARK volunteers to carry out a reserve-wide survey for harvest mouse nests in order to ascertain how widely spread they are across the site.
The team of volunteers from ARK and WMG found 28 nests widely spread, from the river banks, the wetland margins, hedgerows and in rough grassland.
ARK Project Officer and Volunteer Co-ordinator Anna Forbes said, “It is so exciting to continue to discover new species living at Stonebridge. The native hedge that has been planted has brought so many benefits for a wide range of creatures, including it turns out harvest mice!
The presence of the nests in places like the wetland margins and scrub area shows the immense value of ‘wild and messy’ vegetation. If we want wildlife such as the harvest mouse to thrive we need to provide the habitats they need.
Our volunteers will be able to use their new skills on an annual basis at the reserve to monitor the species and we will share the data to help understand distribution of this tiny mouse.”
The harvest mouse is the only British mammal with a prehensile tail, which it uses to grasp plant stems whilst moving through long vegetation. The species is thought to be declining and is nationally rare.
Surveying is carried out late in the year, when the nests (used for breeding, sleeping and resting) are unlikely to be occupied. Nests are not used over winter and vegetation is put back after surveying is carried out.
Stonebridge Meadow is part of Stonebridge Wild River Reserve. The water meadow is jointly owned by ARK and Marlborough Town Council. Volunteering is permitted during Lockdown.