Harvest Mouse - Micromys minutus

The Harvest mouse is the smallest of our British rodents with a body length no bigger than a human thumb.  The fur on the upper side is generally orange-brown and contrasts sharply with the white underside.  The ears are hairy and relatively small but noticeable.  It has beady eyes to see well with and a blunt nose compared to other mice.  It has a long prehensile tail which it uses as a 5th limb for grasping and climbing through stalks of grasses, reeds and tall vegetation.

Wood mouse

Adult Nests

Prehensile tail is long and sparsely hairy, Small, hairy ears, Orange-brown upper coat contrasting with white underside

Very light (5g to 11g)

Confirmation of presence is usually done by searching for their nests.  Submit details of the nest with ruler/measure to show the size, height found and if in use. DO NOT DISTURB THE NEST IF OCCUPIED

Occupies a wide range of habitats from tall herbs, rank grassland, dry reedbeds, wetlands, arable crops (especially oats, wheats and legumes), ditches and bramble patches interwoven with grasses and other tall herbs.  It feeds on seeds, fruit, berries and sometimes catches moths and butterflies.

This mouse does not hibernate but is most active between May and October, however it is mainly nocturnal in the winter.  Due to its size and agility, it is difficult to spot and if alarmed, it may simply drop down to the ground.

Summer nests are spherical, made from grass blades; 8-10 cm diameter and found 30-40 cm above ground.  They are inter-woven firmly among vertical stems with an obvious entrance hole in the side.  Breeding females will build several nests in a season which are green at first, then fade to straw-colour.

Winter nests are often near the ground - in tussocks of coarse grasses (Cock's-foot or Tufted Hair-grass) or rushes.  These solitary nests and much smaller at 5cm diameter, spherical but not as neat as a summer nest.

Breeding season is May to October.  Both sexes are promiscuous and the males do not tend their young.  The female has a maximum of 3 litters per year, with 1-8 young in each (average 5)  She will use different breeding nests to raise her young.  They are fully independent after 40 days but leave the nest at 15-16 days (although they will continue to return to the natal nest until fully mature).

IUCN List = Least Concern  Priority species on the Natural Environment and Rural Communities (NERC) list 

Uncommon in Leicestershire and Rutland.  Poorly recorded across the two counties