Most people think of the harvest mouse as the tiny red-brown animal
clinging to a ripe ear of wheat, however you are just as likely to find
the mouse in a reed bed or clump of cocksfoot grass in an arable field
margin.

The harvest mouse is the smallest rodent in Great Britain , 50-75mm
long and weighing an average of only 5-8g which is about the same as
a 2 pence piece. Its blunt nose, small hairy ears and small size makes
it easy to distinguish from all the other British mice species. It is the only
British animal with a true prehensile tail that can be used as a fifth limb.
It can use the tail to anchor itself in the tail stems of grass and wheat and
together with it’s light weight makes it an excellent climber when feeding in
the stems of cereals and grass.

Harvest mice have a short life span,6 months being the average. Cold
weather , lack of food and predation after harvest causes the population
to crash in winter. Cold and wet weather causes the highest levels of
Harvest mouse mortality , their small size and body weight makes it
difficult to keep warm during the damp cold months.The mice make up
for this during the summer breading rapidly with two or three litters
between late May and September . There are usually around six young
which are born in woven grass nests. The young are born blind and hairless
but grow extremely quickly and start to explore outside the nest by the
eleventh day.

Harvest mice feed around dusk and dawn in the stalks of long grasses
and reeds, for which they need to be extremely agile climbers. In winter
they retreat to ground level, feeding on fallen grass seeds and sheltering
in the bases of thick tussocky grasses.Harvest mice are renowned for
making nests which are woven from living plants such as grasses and
reeds. The mice split the leaves down the veins to keep the strength
in them and use their paws to make the intricate nest in just one night.
They can occur quite low to the ground in tussocky grass, or higher up
in taller vegetation such as reeds.

Harvest mice have many predators: weasels, stoats, foxes, cats, owls,
hawks, crows, even pheasants.They have the ability to sense vibrations
through the soles of their feet from some distance away , giving the mouse
an early warning to the presence of larger animals.

Conservation status

Harvest mice are listed as a BAP (Biodiversity Action Plan) Species
because they are thought to have become much scarcer in recent years
and they require conservation plans to reverse the decline. Changes in
habitat management and agricultural methods are thought to be the main
cause for the loss of populations from certain areas.

Harvest Mouse Facts

Size :                 55-75mm . Weighs from 4 to 11 g
Description:   Brown coat , lighter underside with a long prehensile tail.
Habitat:           Tall vegetation including hedgerows , cereal fields and reeds
Young:              Several litters a year , 2 – 7 young per litter.
Nest:                 Woven compact balls of grass and corn lined with thistle down.
Diet:                  Wheat , barley oats and seeds. Insects , caterpillars and flies.
Lifespan:         Average 6 – 12 months. Occasionally up to 18 months.
Population:     Estimated to be 1.5 million