Habits
The yellow-necked mouse is a much more arboreal species than the wood mouse. The primary habitat is mature deciduous woodland, particularly ancient woodland, but it may also be found in coniferous woodland, hedgerows, orchards or wooded gardens. Nests can be in underground burrows or fallen logs or higher up in tree cavities. In Kent it commonly uses dormouse nest boxes in coppiced woodland or nest tubes in hedgerows.
This species is more aggressive when handled than the wood mouse and can easily bite through a thick plastic bag. It will bite when handled unless firmly ‘scruffed’ (held by the scruff of the neck). However, despite this aggressiveness, a weasel was observed killing a yellow-necked mouse in a car park at the Wildwood Trust in Kent.
The diet of the yellow-necked mouse, whilst being similar to that of the wood mouse, contains a higher proportion of seed. It is also an opportunist; an individual was observed entering an office above an old stable block and over time transferring a large bag full of walnuts into a pair of walking boots. One nut was rolled the length of the office, at least 15 m, and then eaten. Yellow-necked mice have entered the enclosures of captive dormice and killed them, squeezing through 12 mm square mesh.
Reproduction and life cycle
The yellow-necked mouse breeds from February to October but in years when exceptional amounts of forest tree fruits are produced, such as acorns and nuts (mast years); it may also breed in winter. They make a round or cup-shaped nest of leaves, often using fresh green leaves unlike wood mice.
Litters of five to six, exceptionally up to 11 young, are born naked and blind and weaned at 18 days. Those born early in the year can produce two litters themselves, but those born later will overwinter before breeding the following spring.
Distribution, status and conservation
In the UK the yellow-necked mouse is restricted to South and Eastern England and Wales. In Kent it is commonly found at almost every dormouse monitoring site and often comes into houses in winter.
It is sometimes caught by domestic cats. The skulls can be found in tawny and barn owl pellets but they are difficult to distinguish from those of the wood mouse. Other predators include mustelids, foxes and kestrels.
It has an IUCN status of Least Concern. It may be affected by woodland fragmentation but appears able to disperse easily to colonise new areas.
