Science & Tech · Science & Environment · 17 hrs ago
Hazel dormice show a recent rise despite long-term decline
Britain’s hazel dormouse population has recently increased, after a steep decline over the past 25 years.
A conservation report says numbers rose almost 10% between 2020 and 2025, but remain 59% below their level in 2000.
Warmer, drier summers may be helping by improving food supplies and reducing the need for dormice to enter torpor, a deep, energy-saving sleep.
Dormice also hibernate through much of the winter, and researchers say more study is needed to understand how climate change will affect them over time.
Habitat loss and poor woodland management remain threats, and the animals have disappeared from large parts of the countryside.
The recent rise offers some hope, but conservationists say populations are still very low and the species is far from safe.
Researchers and conservationists say continued habitat protection, woodland management and research are needed to support a lasting recovery.
Hazel dormouse numbers in Britain have fallen by 59% since 2000, according to a conservation report.
The population rose by almost 10% between 2020 and 2025, the report said.
Researchers say warmer, drier summers may have helped by increasing food supplies and reducing the need for dormice to enter torpor.
Conservationists say the species remains at critically low levels and faces threats including habitat loss, poor woodland management and climate change.
They say sustained conservation action and habitat protection are still needed.
- Who
- Hazel dormice in Britain. Conservationists and researchers reported on their numbers.
- What
- Their numbers have fallen by 59% since 2000, although they rose by almost 10% between 2020 and 2025.
- When
- The reported decline covers the period since 2000. The recent increase was between 2020 and 2025.
- Where
- Britain.
- Why
- Researchers believe warmer, drier summers may have boosted food supplies and reduced the need for dormice to enter torpor, helping them breed. The sources also cite habitat loss, poor woodland management and climate change as threats.
This story does not have two clearly opposing sides.
Hazel dormouse numbers began the period over which they have since fallen by 59%, according to the report.
The population rose by almost 10%, according to the report.
The BBC and Daily Mail published reports on the dormouse numbers and recent increase.
- Long-term change
- Numbers fell by 59% since 2000
- Recent change
- Population rose by almost 10% from 2020 to 2025
- Species status
- Vulnerable to extinction in Britain on the IUCN Red List
- Local extinctions
- Locally extinct in 20 English counties since Victorian times
- Main threats
- Habitat loss, poor woodland management and climate change
2 sources
What people are saying
Our findings offer grounds for cautious optimism for dormice.
Although the recent upturn is welcome good news, we mustn’t lose sight of the bigger picture: populations remain almost 60 per cent lower than they were in 2000.
This is good news, but we can't be complacent
But dormice are far from out of danger.