Britain's native hazel dormouse (Muscardinus avellanarius) is now vulnerable to extinction. A new report has revealed that the number of the tiny mammal has declined by more than a third since the year 2000.

The "State of Britain's Dormice" report published by the wildlife charity People's Trust for Endangered Species (PTES) reveals that the population of the tiny mammal has dropped, with the current rate of decline at 55 percent over 25 years. The data has prompted concerns about the future of the once very common animal.

Ian White, a dormouse officer at the PTES, said that "[The] Dormice have been around for 40 million years, but their future in Britain is now precarious and there's a pressing need for action to ensure their long-term survival."

What caused their dramatic decline?

Long ago, the Hazel dormouse was a familiar sight throughout England and Wales. But now, the tiny creatures can only be found in the south of England and areas of the English-Welsh border after being lost from 17 countries since the Victorian times. Studies show that they have never been recorded in Northern Ireland or Scotland.

These dormouse live mainly in woods and hedgerows, and can be found weaving ball-like nests in the undergrowth from bark during the summer and hibernating on the ground during winter. But due to the changes in how the woodlands are managed as well as with climate change, these creatures are now finding it difficult to disperse into the wild.

White explained that "the problem within our fragmented landscape is where dormice have become locally extinct within a woodland, without a hedgerow network it is difficult for them to get back there." Warmer winters also prompt these creatures to go in and out of hibernation, forcing them to use more energy which could potentially lead to their death.

Help 'Save the Dormouse'

The PTES launched a dormouse reintroduction scheme back in 1993. The program is aimed at improving the creature's habitat so they can reintegrate back into the wild.

Since the launch of the scheme, the wildlife charity has made 26 releases involving 864 dormice at 22 different locations. The organization has revealed that 21 out of the 26 dorrmouse released are showing signs of success.