Dormouse Hibernation Welfare: Cold-Weather Survival and Conservation

The hazel dormouse (Muscardinus avellanarius) is one of Britain's most vulnerable small mammals, with hibernation welfare and habitat quality being critical conservation concerns.

Key Facts

Hazel dormouse populations have declined by over 70% in the UK since the 1990s due to woodland degradation.
Dormice hibernate from October to April, during which their body temperature drops to near-ambient and metabolic rate falls by 95%.
Premature arousal from hibernation depletes fat reserves and can be fatal — disturbance during winter is a major welfare threat.
They are entirely dependent on a mosaic of connected coppice and hedgerow habitats for foraging and nesting.
The People's Trust for Endangered Species (PTES) coordinates the national dormouse monitoring programme.

Welfare Considerations

Dormouse welfare during hibernation is critically dependent on stable, cool (but not freezing) nest temperatures and minimal disturbance. Nest boxes sited inappropriately in exposed positions or disturbed during winter surveys cause potentially lethal arousal. Researchers following PTES protocols handle hibernating dormice briefly only in winter surveys, using minimal disturbance protocols. Welfare during the active season includes risks from woodland management activities (hedge-cutting during nesting season) and predation from domestic cats. Habitat connectivity is a welfare issue at the population level — isolated populations face genetic bottlenecks and local extinction. Dormouse reintroduction programmes include welfare monitoring of released animals using passive transponders.

What You Can Do

Join your local dormouse monitoring group through People's Trust for Endangered Species.
Plant hazel, honeysuckle, and bramble in your garden or local area to provide dormouse habitat.
Avoid disturbing woodland during April-October nesting season.
Fit dormouse nest boxes in suitable woodland under PTES guidance.
Support Woodland Trust coppice restoration projects which are critical for dormouse recovery.