The harvest mouse is Britain’s tiniest rodent and is extremely elusive. Cumbria Biodiversity Data Centre (CBDC) is asking for help to find out where these creatures are living in Cumbria.

In the past the harvest mouse has been found across the county. However, since 2000 it has only been seen in South Cumbria apart from Derek’s nest in the north!  CBDC is asking wildlife lovers to search in long grass and look for harvest mice nests.  The nests look like a ball of loosely woven grass about 5-10cm across.

John Martin of Cumbria Mammal Group said, “The harvest mouse lives in nests it builds in tall grasses and tussocks in fields, hedges and in reedbeds. At this time of year, it is possible to find the nests as the vegetation is dying back and leaves have fallen from hedges”

Harvest Mice photographed by Derek Crawley

“Look for an area of grassland that has not been mown or disturbed, for example at the bases of hedges and along the edges of minor country roads.  Try to spot last summer’s nests woven around grass or reed stems or winter nests in grass tussocks at ground level.  Carefully part the tussocks with gloved hands to find the low-level nests but be careful as they can contain live mice! If you find a nest please take a photograph and let CBDC know when, where and what you have found.  Woodmice, voles and some small birds make nests similar to a harvest mouse; photographs will help distinguish what type of nest it is.”

The Atlas of Mammals of Great Britain and Northern Ireland published in March 2020 shows that the harvest mouse has undergone a marked decline over the last 30 years.  Some of this may be down to fewer people looking for it.  

Derek Crawley from the Mammal Society told us, “In counties where training and surveys have been developed numerous records have been forthcoming. The society is happy to help CBDC in any way it can to find this elusive mammal.  The Mammal Society is going to hold its own national harvest mouse survey in 2021-22 to establish the true UK distribution of the harvest mouse.”

For further information about how to get involved visit CBDC website and follow the links or post your photographs on CBDC’s Facebook page.