Populations of the hazel dormouse, perhaps the most elusive native British mammal, have plummeted by 70% this century.
The nocturnal, tree-dwelling animals are now extinct in 20 counties in England and the species must be reclassified as “endangered” on the International Union for Conservation of Nature red list, according to a study by the People’s Trust for Endangered Species (PTES).
The key factor in their decline is the loss of the scrubby under-storey in woodlands where the arboreal dormice live and feed in spring and summer, but the problem has been compounded by climate change, according to conservation scientists.
Dormice hibernate for six months in nests below ground but milder winters mean they are increasingly emerging from hibernation when there is no food available. Between 40% and 70% of dormice die during the hibernation period.