British Mice

Harvest Mouse

The Harvest Mouse (Micromys minutus) is a small rodent native to Europe and Asia. It is the smallest rodent in Europe. In Britain, it is common in parts of Wales and from Yorkshire southwards in England, however, it is not found on high ground.

The Harvest Mouse pre-breeding season population is estimated to be 1,425,000.

Harvest Mouse Description

Harvest mouse

The Harvest mouse measures between 5 and 7 centimetres in length, has a tail 6 centimetres long and weighs 5 – 11 grams, some weighing less than a two pence coin. The Harvest mouse has a coat of fur which is coloured reddish/brown, sometimes yellow/brown.

It has white, furry underparts, small furry ears, a blunt muzzle/nose and it is the only British animal with a truly prehensile tail that can be used as a fifth limb. This prehensile tail is long, scaly, ringed and thinly haired. When wrapped around a stem, the prehensile tail can act as a brake or anchor. This makes the mouse very nimble when traveling and feeding in stems of cereals and grasses.

Harvest mice have a remarkable ability to sense vibrations through the soles of their feet. Larger animals nearby can be sensed by vibrations passing through the ground and up the plant on which the mouse is feeding.

Harvest Mouse Habitats

Harvest mice move around as seasons change. They prefer tall, dense vegetation including reed beds, hedgerows, reed beds, allotments, roadside verges, gardens as well as cereal sown fields, particularly, cornfields and undisturbed areas.

Non-breeding nests are constructed of loosely woven, shredded grass at the bottom of plant stems, under rocks or in abandoned birds nests. The summer breeding nests are the size of an orange, compact balls of grass or corn blades interwoven among shrubs or stalks, often in standing corn and lined with thistle down. Breeding nests are built in stems high above the ground. The spherical nests are about 10 centimetres in diameter. Non-breeding nests are smaller (5 centimetres in diameter) and may be built closer to the ground or in buildings.

Harvest Mouse Diet

The Harvest mouse mainly feeds up on seeds, fruits, nectar and bulbs, however, a tiny proportion of their diet is made up of insects, particularly in the summer, as well as roots, moss and fungi. Some food is cached underground for the winter. Other foods include wheat, barley, oats, shoots, flies and caterpillars.

Harvest Mouse Behaviour

Harvest mice are cathemeral which means they are active day and night, although most activity occurs at dusk. They do not hibernate, however, they spend most of their time underground in the winter.

Harvest Mouse Reproduction

Harvest mouse breeding season ranges from May to October. The female Harvest mouse has a gestation period of 17 – 19 days after which a litter of 1 – 8 young are born. Three litters may be produced per year, sometimes several. The female mouse abandons the young after 15 – 16 days, however, the young may still use the nest for a further few days. A new nest is built for each new litter. Around 99% of adult mice do not survive the winter. Harvest mice have an average life span of between 12 – 18 months.

Harvest Mouse Conservation Status

Harvest mice are categorised as Lower Risk by the IUCN Red List. Modern farming methods have caused a reduction in hedgerows, and combine harvesters leave harvest mice in grain fields with little chance of escape.

Conservation efforts have taken place in England as of 2001. Tennis balls used in play at Wimbledon have been recycled to create artificial nests for harvest mice in an attempt to help the species avoid predation and come back from being a near-threatened status.

Wood Mouse

The Wood Mouse (Apodemus sylvaticus) is also known as the Long-tailed Field Mouse. It is the commonest and most widespread mouse species that resides in the British countryside. This rodent was recognised as a distinct species in 1894.

The Wood Mouse is a close relative of the rarer yellow-necked mouse (Apodemus flavicollis). It differs slightly in that it has no band of yellow fur around the neck, is slightly smaller in size, darker in colour and has smaller ears.

The pre-breeding season population of Wood mice is estimated to be in excess of 38 million.

Wood Mouse Description

Wood Mouse

Fully grown Wood mice measure around 8.1 – 10.3 centimetres from nose to tail. Their tails measure 7.1 – 9.3 centimetres in length and they weigh 13 – 27 grams. Wood mice gain weight during the summer. Wood mice have generally dark brown fur on the top part of their bodies with white/grey undersides. They have large protruding eyes, large ears and long tails.

Wood Mouse Habitats

Wood mice are found in fields, gardens, woods, scrubs, open grasslands and hedgerows throughout Britain and Ireland. They live in underground burrow systems, usually under the roots of trees, that contain a series of nest chambers, runs and food stores. Nests usually consist of a ball of dry grass, moss and leaves. However, the Wood Mouse will live just about anywhere there is plenty of food and shelter.

Wood Mouse Diet

The Wood mouse has a varied omnivorous diet, eating nuts, berries, seeds, acorns, haws, seeds, fungi, spiders and rose hips as well as small insects and larvae. They will also eat invertebrates, worms, carrion (dead animal carcasses) and other similar food. Food is stored in underground burrows or occasionally in disused bird nests.

Wood Mouse Behaviour

If caught by its tail, a wood mouse can quickly shed the end of it, however, it may never regrow. The wood mouse does not hibernate and, despite its name, it prefers hedgerows to woodland.

The wood mouse is mainly nocturnal. It will sit up and wash itself all over, especially if scared. The Wood mouse is an excellent climber and will leap high in the air when disturbed. They have superb hearing and excellent vision (hence the large eyes and ears). Unfortunately, it has many enemies including weasels, stoats, cats, foxes, moles and owls. They are a vital source of food for other larger nocturnal hunters particularly owls.

Wood mice nest wherever there is cover and warmth, this usually means below ground however, they can also be found in hedgerows, buildings, car radiators and other similar dwellings.

Wood Mouse Reproduction

Wood mice breed from March to October, with a breeding peak from July to August. They produce 4 – 7 litters consisting of 2 – 9 young per year. Wood mice can reproduce quite frequently with the gestation period around 25 days. Females can breed at the age of 2 months. Young mice are usually out on their own after 4 weeks. This short parenting enables them to breed often. Wood mice have a life span of around 18 – 20 months, however, very few survive 2 winters. They tend to have a shorter life span of 6 – 12 months in the wild as many creatures prey on them . They live longer in captivity and when conditions are favourable.

Wood Mouse Conservation Status

Wood mice are common and are not considered to be an endangered species.

Yellow-Necked Mouse

The Yellow-necked Mouse (Apodemus flavicollis) is closely related to the wood mouse, with which it was long confused, only being recognised as a separate species in 1894. It differs in its band of yellow fur around the neck and in having slightly larger ears and usually being slightly larger overall. When sitting upright its characteristic yellow-brown collar patch can be seen, distinguishing it from the wood mouse.

In Britain, they are concentrated around the Welsh borders, the western Cotswolds and south-eastern counties. As with the wood mouse, they range across Europe through to Central Asia, however, they range further North in Scandinavia than the wood mouse.

Yellow-necked mice are rarer in Britain than the Wood mice. They are mainly restricted to southern England and Wales.

The Yellow-necked mouse pre-breeding season population is estimated to be up to 750,000.

Yellow-Necked Mouse Description

Yellow-Necked Mouse

Yellow-necked mice measure around 9 – 1.3 centimetres in length from nose to tail and have a tail length of 9 – 13.5 centimetres. They weigh between 15 and 30 grams. Both Yellow-necked mice and Wood mice are larger than House mice.

Yellow-necked mice have dark brown fur on the top parts of their bodies with paler undersides and orange coloured flanks. They have a yellow collar patch, large protruding eyes, large ears and long tails.

Yellow-Necked Mouse Habitats

Yellow-necked mice have home ranges generally of less than 0.5 hectares, which often overlap with other individuals.

The Yellow-necked mouse prefers mature woodlands, hedgerows and wooded gardens. They Nest below ground, under the stumps or roots of trees and their nests consist of a ball of dry grass, moss and leaves.

Yellow-Necked Mouse Diet

The Yellow-necked mouse is an omnivore and feeds up on seedlings, buds, fruit, nuts, insects, larvae and spiders. Their food is stored in underground burrows or occasionally in disused bird nests. Their diet is similar to that of the Wood mouse.

Yellow-Necked Mouse Behaviour

Yellow-necked mice are nocturnal and are agile climbers. They can climb trees and sometimes overwinter in houses.

Yellow-Necked Mouse Reproduction

Yellow-necked mice breed from February to October, with a breeding peak from July to August. Usually, 3 litters of 3 – 10 young are produced per year. Gestation period lasts for 23 days. The young are weaned after 3 weeks. Their distinctive yellow collars become visible after 2 weeks, at about the same times as they first open their eyes.

The Yellow-necked mouse has a life span of 12 – 24 months. Very few survive two winters.

Yellow-Necked Mouse Conservation Status

Worldwide, yellow necked-mice are considered to be common and therefore not classed as an endangered species.