There’s No Hazel on My Site. Do I Still Need a Dormouse Survey?
“There aren't any hazel trees on the site, so surely we don't need a hazel dormouse survey?”
Not necessarily.
Despite their name, hazel dormice aren't restricted to hazel woodland. They can use a variety of structurally diverse habitats, including woodland, hedgerows and scrub.
So when assessing whether dormice need to be considered for a development, an ecologist looks at much more than whether hazel happens to be present.
Where do hazel dormice live?
Hazel dormice are often associated with species-rich deciduous woodland, but they can occupy a much broader range of habitats.
Suitable habitat can include:
broadleaved and mixed woodland;
some coniferous woodland;
dense scrub;
species-rich hedgerows; and
connected networks of woody vegetation.
Natural England's current planning advice specifically identifies woodland, including deciduous, conifer and mixed woodland, hedgerow and scrub when considering whether dormouse surveys may be required.
The structure and connectivity of the habitat can be just as important as the presence of one particular plant species.
Why are hedgerows important?
Dormice are predominantly arboreal and can use hedgerows to move between areas of suitable habitat.
A hedgerow may therefore be more than an isolated landscape feature: it can form part of a wider habitat network connecting woodland and scrub.
Fragmenting that network can potentially be detrimental, even where relatively little habitat is physically removed.
Natural England advises that remaining habitat should either be large enough to support a dormouse population or remain linked to other suitable habitat, dormice shouldn't simply be left within small, isolated habitat fragments.
What if there are no dormouse records nearby?
An absence of records doesn't necessarily demonstrate absence.
It may simply mean that nobody has surveyed the area.
Natural England advises planning authorities to consider both known distribution and historical records and the habitats affected by a proposal when deciding whether dormouse surveys are appropriate.
This is why ecological desk studies and habitat assessments are often considered together rather than relying solely on a database search.
What does a dormouse survey involve?
The appropriate method depends on the site and the likely impact.
For smaller-scale works, Natural England identifies methods including searches for nests and characteristically opened hazelnuts.
For projects with potentially greater impacts, survey techniques can include nest tubes, nest boxes or footprint tracking tunnels.
Some survey activities involving dormice require an appropriately licensed ecologist.
If dormice are found in one part of the site, does that only protect that spot?
This is an important point.
Natural England's standing advice says that where dormice are found on part of a development site, they can be assumed to be present within suitable habitats across the whole development site.
The ecological assessment therefore needs to consider how the wider habitat network is being used rather than treating an individual nest tube or nest as an isolated constraint.
Are dormice legally protected?
Yes.
Hazel dormice are a European protected species, protected under the Conservation of Habitats and Species Regulations 2017 (as amended). They also receive protection under the Wildlife and Countryside Act 1981 (as amended).
Among other offences, it is illegal to deliberately capture, injure, kill or disturb hazel dormice, or to damage or destroy their breeding sites or resting places. Breeding sites and resting places remain protected even when dormice aren't physically present at the time.
Additional offences under the Wildlife and Countryside Act include intentionally or recklessly disturbing dormice while they occupy a place used for shelter or protection, or obstructing access to such a place.
Hazel dormice are also a species of principal importance for the conservation of biodiversity in England under Section 41 of the Natural Environment and Rural Communities Act 2006.
Development affecting dormice may therefore require appropriate mitigation and, where works would otherwise result in an offence, a licence from Natural England.
Does finding dormice mean development can't proceed?
Not automatically.
The first objective should normally be to avoid impacts.
That could involve retaining important woodland, scrub or hedgerows, maintaining connectivity through the site or adjusting the development layout.
Where impacts can't be completely avoided, appropriate mitigation and compensation may be required. Depending on the impacts, a Natural England mitigation licence may also be necessary.
Translocation is very much a last resort: Natural England specifically notes that dormice can become stressed easily and says it will only grant a licence to translocate them where there is no reasonable alternative habitat close by.
Why is early assessment particularly important?
Dormouse surveys can affect project programmes.
Unlike a habitat assessment that might be undertaken relatively quickly, establishing dormouse presence or likely absence can require surveys during appropriate periods of the year.
Natural England currently expects survey information to be from the current or previous active season, although surveys up to three years old may be acceptable where habitats haven't significantly changed.
Discovering the requirement after a planning application has been submitted can therefore cause avoidable delays.
The key message
No hazel doesn't mean no dormice.
When deciding whether hazel dormice need to be considered, the important questions are whether the site is within their potential range, what habitats are present, how those habitats connect to the surrounding landscape and how the development could affect them.
For projects involving woodland, hedgerows or scrub, considering dormice at an early stage can help identify constraints while there's still flexibility to design around them.
This article relates to hazel dormice and development in England and reflects Natural England guidance available in September 2026. Survey and licensing requirements should always be determined for the individual project.
Contact us if we can help with your project at www.nichecology.co.uk or on 07351153157 and we would be happy to help.
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