Hazel Dormouse – Muscardinus avellanarius
Dormice live at low population densities (one tenth as abundant as bank voles and wood mice in the same habitats).
Re-introductions of dormice are often suggested, but these require suitable areas of woodland habitat and long periods of supplementary feeding. Breeding dormice in captivity is difficult and wild-caught animals are unlikely to be available in sufficient numbers. If fewer than 20 animals are released there is a high risk of failure. However, they have been success-fully reintroduced since 1992 to several counties (including Cheshire, Cambridgeshire, Derbyshire).
Orange/yellow fur; distinctive thick furry tail. Very large eyes as it is nocturnal. Head and body length 60-90mm, tail length 50-70mm.
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Nests: Dormice will build nests in hazel woodland and are found in tree holes and amongst dense thorny scrub and hedgerows. They are 100-150 mm in diameter woven in low growing shrubs. Dormouse nest tubes are available from The Mammal Society.
Feeding signs: Small rodents all open hazel nuts by nibbling a relatively neat round hole in the shell. Squirrels and birds split the shell completely in half or make jagged holes in it. Dormouse chewed hazel nuts have a smooth inner rim with tooth marks at an angle to the hole on the nut surface.
Harvest mouse (Micromys minutus)
Much smaller than hazel dormouse. Golden-brown on top with pale grey/white underside, whilst hazel dormouse is orange/yellow on top and has yellow underside. Brown/pink prehensile (able to grip) tail, differing from non-prehensile, very furry tail of hazel dormouse. Dormouse has larger, more prominent black eyes and black whiskers.
House mouse (Mus domesticus)
Grey/brown fur all over, compared to hazel dormouse coat which is orange/yellow on top and yellow underneath. Brown/pink tail with little fur, unlike very furry tail of hazel dormouse. House mouse has more prominent ears than dormouse, but smaller eyes, as dormouse eyes are big and black.
Wood mouse (Apodemus sylvaticus)
Red/brown on top and pale (often white) underside with yellow/orange streak between forelegs. Hazel dormouse has orange/yellow fur on top with yellow fur on underside. Hazel dormouse has a very furry tail which wood mouse does not have. Ears of wood mouse are larger and more prominent. Eyes of hazel dormouse are larger and more prominent.
Yellow-necked mouse (Apodemus flavicollis)
Red/brown fur on top with pale (often white) underside, whereas hazel dormouse has orange/yellow coat on top and yellow underside. Ears much larger than those of the hazel dormouse and tail is much less hairy, with darker fur along top of tail, whilst dormouse tail is orange/yellow all over and very furry. If you get a closer look: unbroken yellow band across neck, joining forelegs, not present on hazel dormouse.
Voles are different to mice in that they have a more rounded muzzle, whilst the muzzle of a mouse is pointed. Voles have smaller eyes and smaller, more subtle ears that are often covered by fur. Mice eyes and ears are large. Voles often have shorter tails. There are of course exceptions: water voles have long tails and it is often said that harvest mice have vole-like proportions as they have a more rounded muzzle and subtle ears and eyes.