• First season of National Harvest Mouse Survey 2021 – 22 success
  • Just under 1,500 nests were recorded compared to on average 69 records for the past 30 years on National Biodiversity Network
  • Harvest mice were found in a further 40 survey sites compared to those historically surveyed 
  • Harvest mice were recorded in Scotland for the first time
  • Field margins and road verges were the habitats which had the highest chance of finding a nest in

We’re pleased to announce the success of our first National Harvest Mouse Survey season. From October 2021 until March 2022 the Mammal Society encouraged the public across the UK to help search for harvest mouse nests.

Classified as Near Threatened with extinction (Red List for Britain’s Mammals) very little is known about the current population or distribution of the harvest mouse. The harvest mouse is thought to be an indicator of the health of an ecosystem, predominantly found in farmland, so declines are thought to be caused by changes in habitat management and agricultural practices. 

This is why the Mammal Society set out to develop a monitoring strategy for harvest mice. We also want to establish a national community of surveyors, encourage increased recording of this species and ultimately create a conservation management plan. 

Zeb Soanes, Mammal Society Patron explains “Understanding more about this tiny species is so important. The harvest mouse is an important indicator species for the health of arable habitat, so understanding where they are found can help the Mammal Society reinforce the case for responsible farming practices and support for enhanced protections that align with that. Please do become a harvest mouse hero and support this survey!” 

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(C) Harvest Mouse by Gary Chisholm

The first survey season found just under 1, 500 harvest mouse nests from over 900 searches. On average 1.96 nests were found per survey and one survey even found 46 nests in a day. Nearly 30% of surveys found more than one nest and harvest mice were found to be present in 74% of the area surveyed. Additionally, harvest mice were found on a further 40 survey sites beyond those historically surveyed. Most notably in Scotland where this species is Critically Endangered (Red List for Britain’s Mammals).

We also asked volunteers to record which type of habitat nests  were found in. Field margins and road verges had higher than average ‘nests found per hour of search effort’ suggesting that these are important habitats for the harvest mouse. Saltmarsh, marsh and wet grassland were also found to be important. 

“The initial survey season got off to a fantastic start increasing the reporting of this species and laying the foundations for a community of harvest mice surveyors.” says Dr Frazer Coomber. “However, in order to start assessing the status of this species we need to collect more data from across a larger geographical extent. I am excited to launch this year’s survey season in October which we at the mammal society have been working tirelessly on. We want to increase the community of surveyors and now have many more people in places across the country helping us.”

One of our main aims for this survey was to increase reporting and recording of harvest mice. For the past 30 years there has been on average 69 records of harvest mice per year submitted on NBN (National Biodiversity Network). In one year we managed to achieve nearly 1,500 records, showing we have clearly achieved this aim. Additionally we wanted to establish a community of surveyors to help search for nests over the coming years. Of those surveyed from the first year, 100% would like to participate in the survey again, supporting one of our core aims. We plan to repeat the National Harvest Mouse Survey into the future to increase our knowledge of this species to create a robust conservation management plan.