Hazel dormouse populations in England and Wales show recent recovery

The National Dormouse Monitoring Programme, led by the People's Trust for Endangered Species, found that hazel dormouse numbers in England and Wales increased between 2020 and 2025.

This rise follows a long period of decline where the population dropped by nearly 60% since the year 2000. Scientists believe that warmer and drier springs and summers helped the small rodents survive.

These warmer conditions may increase food supplies and reduce the amount of time the animals spend in torpor, which is a state of deep sleep used to conserve energy during cold or wet weather. With more energy available, the animals can spend more time feeding and breeding to build up fat reserves for winter.

Conservationists warn that while the population grew by almost 10% during the recent five year period, the numbers remain much lower than they were two decades ago. Researchers note that the species has already disappeared from around 20 English counties due to woodland loss. Experts say the community must continue to manage woodlands and protect hedgerows to ensure the long term survival of the species as climate change continues to affect their environment.