Description: Similar to their close relative, the wood mouse, with long tail and large ears and eyes. Brown back and white belly with distinctive band of brownish-yellow fur across the neck area. Slightly larger than the wood mouse and often livelier. The yellow-necked mouse was only identified as a separate species from the wood mouse in 1834.
Size: Head and body 95-120mm, tail 77-118.
Lifespan: Average life expectancy is 3-4 months but they can live for a year or so.
Breeding: Breeding season is February to October and a female will produce multiple litters of 2-11 young. They are born blind and naked and weigh around 2.8g. Their eyes open after 13-16 days and the collar is a grey colour that will turn yellow as they mature.
Habitat: Mainly mature woodland but also hedges and gardens and will sometimes venture into houses.
Diet: Tree seeds, fruit, some green plants and small insects. Similar to the wood mouse.
General ecology: Range is usually slightly larger than the wood mouse, but rarely more than 0.5 hectares, though this may increase for males in the spring. Largely nocturnal, they are good jumpers and climbers. They live mainly in underground burrow systems with multiple entrances, using plant material as bedding, but they are sometimes also found in tree holes or dormouse boxes.
Distribution and main sites: The yellow-necked mouse is native to Britain but is only commonly found in southern Britain and the Severn Basin from Gloucestershire up to Staffordshire. It has often been found in Shropshire, particularly in ancient woodland sites such as Wenlock Edge.
Local survey history: Surveys are regularly carried out in various locations, including Whitchurch, Shrewsbury, Preston Montford, Ironbridge, Wenlock Edge, often by, or on behalf of, organisations such as Shropshire Mammal Group, National Trust, Shropshire Wildlife Trust, Ironbridge Meadows Group.
Conservation status: Not as common as the wood mouse but not a protected species. In 1998, the Mammal Society launched a national survey to try to update records on the species and found there had been no major decline in numbers or change in the known range, suggesting no urgent conservation needs.
Threats: Main threats are changes in land use and loss of ancient woodland. Herbicides and pesticides may also be a threat.
Main recording methods: Small mammal surveys are carried out in some areas of Shropshire using live traps (Longworth and/or BioEcoSS tubetraps) to record the population of specific areas. Common field signs include burrows and pathways in undergrowth. Piles of nuts with neatly nibbled holes in them are also a sure sign of voles or mice though the particular species may not always be easy to discern (see below).
Did you know? These mice can shed the skin of their tail to escape attack. The skin does not grow back, however, so this trick can only be used once
Distinctive neatly nibbled holes in hazelnuts are a typical sign of the presence of mice or voles but it is often difficult to distinguish between those nibbled by each species. Nuts that have been nibbled by wood mice or yellow-necked mice tend to have vertical tooth marks across the rim of the hole. Similar teeth marks are left by bank voles but those nibbled by yellow-necked mice and wood mice tend to be messier. Nuts that have been nibbled by dormice tend to be smoother and more circular, as they nibble round the hole rather than across the rim
Acknowledgements: The Mammal Society, the Wildlife Trusts, Wikipedia
Text: Charlotte Huntly
Photo credits: Paul Bell, Malcolm Monie and Charlotte Huntly
© Shropshire Mammal Group 2020