Other Mammal Species – Rodents

For many people rodents are the least appealing group of mammals we have in Britain. Most rodents tend to be under-reported and consequently many of the maps here probably understate the range of the species in Dorset.

With the exception of common rats which are commonly seen even in urban areas most British rodents are difficult to see and most people only encounter the odd mouse or vole often brought home by the family cat. However even records of dead animals help build up a picture of a species’ distribution so records of dead animals brought in by the family cat are well worth reporting. If you are unsure what species is involved a photograph, even taken on an IPhone, will help confirm the record.

Small mammal trapping offers the best chance of finding many small rodents and companies such as NHBS sell a wide range of small mammal trips from cheap trip-traps at £4.50 to the long-established Longman traps at upwards of £60 at the upper end of the range. Please remember if you are trapping small mammals that shrews can also be caught in small mammal traps. However a licence is required to do so and particular care must be taken when trapping rodents to ensure that a dead shrew does not become the unfortunate bi-product of the trapping session. Please see our page on mammals and the law for more details.

Other opportunities for finding small rodents include watching areas around bird feeders in winter, wood mouse and bank vole being regular visitors to bird tables, and checking nest boxes in winter for mice and voles.

Finally many rodents leave distinctive tooth marks on nuts in autumn and checking for signs such as these can help identify what rodents occur in a particular area.

Common (Brown) rat Rattus norvegicus

Common throughout Britain with the exception of a few small offshore islands and exposed mountain regions. The largest rodent and should not be confused with other species although swimming rats can be misidentified as water voles by the unwary.

mammal-rat

Status in Dorset:

Almost certainly under-reported and far more common and widespread than the map indicates. Commonly found in both urban and rural areas.

House Mouse Mus musculus

Like common rat found throughout mainland Britain and most offshore islands but thought to be over 20% scarcer than common rat with an estimated pre-breeding population of 5 million compared to 6.79 million common rats. Found mainly around buildings and farmland.

mammal-housemouse

Status in Dorset:

Sparsely distributed across Dorset but probably grossly under-reported.

Yellow-necked Mouse Apodemus flavicollis

Mainly restricted to mature deciduous woodland in southern Britain although will enter housing particularly in winter. When trapping small mammals it should be remembered that young wood mice can also have a yellow spot on the throat. True yellow-necked mice are larger and much more aggressive being prone to trying to take a bite out of your finger.

mammal-yellowmouse

Status in Dorset:

Sparsely distributed in suitable habitat.

Wood Mouse Apodemus sylvaticus

Found throughout Britain other than on exposed mountainous areas. Britain’s commonest mouse with an estimated pre-breeding population of 38 million. Found in houses as often if not more often than house mouse.

mammal-woodmouse
Photo: Colin Varndell

Status in Dorset:

Given its British status not surprisingly Dorset’s most widely reported small mammal.

Harvest Mouse Micromys minutus

Within Britain largely restricted to England and Wales. Favours tall dense vegetation including but not exclusively grassland, reedbeds and cereals and other crops. Best located by finding its characteristic nest of woven grass leaves at the end of the summer and in early winter. Can be attracted to seed in reedbed habitats in winter but most often seen during targeted small mammal trapping sessions.

mammal-harvestmouse
Photo: Colin Varndell

Status in Dorset:

Sparsely distributed in suitable habitats.

Hazel Dormouse Muscardinus avellanarius

At 10-30g and 50 mm our smallest and to many people most appealing rodent. Largely restricted to southern England and Wales with three isolated populations in NW England. Found in deciduous woodland and overgrown hedgerows with well-developed scrub layers. Unfortunately difficult to see in the wild and best seen by checking nest boxes with a licenced dormouse worker. The Peoples’ Trust for Endangered Species regularly organise dormouse days around the country.

mammal-hazeldormouse
Photo: Colin Varndell

Status in Dorset:

Widespread but particularly common in the west of the country where the species is the subject of an ongoing research and conservation programme.

Edible Dormouse Glis glis

First introduced to Tring Park in Hertfordshire in 1902 edible dormice are now well established in Hertfordshire and the nearby Chilterns and have recently been found as far east as Harlow in Essex.

mammal-edibledormouse

Status in Dorset:

Odd records are likely to reflect local escapes rather than animals expanding their range from further north.

Water Vole Arvicola terrestris

The much loved ratty from Wind in the Willows water voles have sadly declined dramatically and disappeared from whole catchment areas in several areas of Britain principally as a result of predation by introduced american mink. Reintroduction programmes are underway in many areas but recolonisation remains slow particularly in areas where mink remain common.

mammal-watervole
Photo: Colin Varndell

Status in Dorset:

Still pleasingly relatively widespread although the good coverage compared to other rodents may well simply represent the amount of time spent surveying suitable habitat for otters and water voles rather than a true representation of its relative abundance compared to other species. Swimming rats can be misidentified as water voles by the unwary and some reported records may well be misidentifications. Some reserves such as Brownsea Island and Radipole Lake offer good opportunities to see water voles in the county.

Bank Vole Myodes glareolus

Widespread in mainland Britain with an estimated pre-breeding population of 23 million. Found in a wide variety of habitats with thick ground cover, and the most likely vole to be encountered in gardens, at bird feeders and in nest boxes in winter. Longer tailed than (short-tailed) field vole and also has more prominent ears.

mammal-bankvole
Photo: Colin Varndell

Status in Dorset:

Widespread but under-reported.

Field Vole Microtus agrestis

With an estimated pre-breeding population of 75 million Britain’s commonest vole although more restricted in habitat than bank vole mainly occurring in rough ungrazed grasslands with other populations in a range of more marginal habitats. A favourite prey item for kestrels and owls.

mammal-fieldvole
Photo: Colin Varndell

Status in Dorset:

As bank vole widespread but under-reported.

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