Volunteers Needed to Support National Harvest Mouse Survey in Wales
Natural Resources Wales (NRW) is calling on volunteers across Wales to take part in the upcoming National Harvest Mouse Survey, led by The Mammal Society.
Wales is currently underrepresented in the National Harvest Mouse Survey, and NRW is keen to encourage greater participation to help fill these data gaps. Every new record will contribute to a clearer understanding of the species’ distribution and inform future conservation efforts.
The harvest mouse is one of Wales’ smallest and most elusive mammals, known for its delicate woven nests hidden in tall grasses. Despite its charm, the species remains under-recorded in Wales, making it difficult to assess its true status and distribution.
NRW has supported harvest mouse surveys in the past, notably during the Mammals in a Sustainable Environment project (2011–2015), which uncovered previously unknown records of the species. However, data remains limited.
In 2020, NRW commissioned the State of Mammals in Wales report, which highlighted the harvest mouse’s conservation status as Vulnerable, with poor future prospects. The estimated population in Wales is around 34,000, but this figure carries considerable uncertainty due to insufficient records.
The survey season runs from October 2025 to March 2026, a period chosen to avoid disturbing breeding nests. Surveys are quick and simple to carry out, and no prior experience or specialist equipment is needed. To survey for harvest mice, look for tennis ball-sized nests made of tightly woven long grass that compress easily without much pressure.
Liz Halliwell, Terrestrial Species Team Leader for Natural Resources Wales, said:
“This is a great opportunity for people across Wales to get involved in wildlife monitoring and make a real contribution to conservation. Whether you’re a seasoned naturalist or just curious about your local wildlife, your help could make a big difference.”
Matt Larsen-Daw, CEO, The Mammal Society:
"Good conservation outcomes depend on good data, but our smallest mammals such as the charismatic harvest mouse are under-recorded, despite their pivotal importance in ecosystems.
“Seeking signs of harvest mice is a rewarding and fun way that anyone can take action to support nature recovery, from experienced naturalists to first-time volunteers and children. Finding nests or confirming that there are no signs of presence are equally important to help scientists understand how this important species is doing, and how it is being affected by human activity and climate change."
To learn more about harvest mice and how to get involved, visit The Mammal Society’s harvest mouse survey page.
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*Image Copyright: Derek Crawley.*