Endangered dormice get tunnels to cross the road

The hazel dormouse, Muscardinus avellanarius, is found in only half the areas it inhabited a century ago and only 10,000 remain in Britain. The creature could disappear if the slump is not reversed.

Fragmentation of its woodland habitat is the biggest threat because the animal is so scared of being torn apart by tooth, claw or talon that it generally refuses to cross open ground, whether roads, tracks or fields.

The combination of fragmented habitat and fear of open spaces means that many dormouse populations are at risk of dying out because numbers are too low to provide a big enough gene pool for long-term survival. By offering the nocturnal animals a route across roads, tracks and even between gaps in the remaining hedgerows, habitats can be linked.

Conservationists have found that two types of mesh tunnel work best: a large empty tunnel, favoured by males, and a smaller one for females, filled with sisal, a straw-like material. One of the females in the trial was so impressed that she did what dormice do best - she built a nest in it and went to sleep

The test route, part of a project funded by the People's Trust for Endangered Species, was built as a bridge above a path in a wood in Herne Bay, Kent. It was formed of four wire mesh tunnels, of two sizes. One of each was left empty while the other was filled with sisal, which is used for ropes. Infra-red sensors detected the differing preference of males and females.

— The only native dormouse in Britain is the hazel dormouse, also known as the common dormouse. They live for about five years

— They can add 75 per cent to their body weight in preparation for hibernation

— Their name derives from the French word dormir (to sleep)

— They hibernate for seven months of the year and will take extended naps during summer months. Up to 75 per cent of a dormouse’s life may be spent sleeping

— Their diet consists mainly of nuts, seeds and flowers of hazel, oak, bramble and honeysuckle

— Dormice spend most of their time in the treetops, where their bushy tails give them good balance. They nest in tree hollows, and can weave their own nests from shredded twigs and bark

— Dormice generally have one or two offspring a year

— Edible dormice, Glis glis, are the largest species and were eaten by the Romans. They were introduced to Britain in 1902 and are found in the Chiltern Hills