Hazel dormice: advice for making planning decisions
Source: gov.uk (2025-04-23)

How to assess a planning application when there are hazel (common) dormice on or near a proposed development site.

This is Natural England’s ‘standing advice’ for hazel (common) dormice. It is a material planning consideration for local planning authorities (LPAs). You should take this advice into account when making planning decisions. It forms part of a collection of standing advice for protected species (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications#standing-advice-for-protected-species).

You should read this guidance alongside Protected species and development: advice for local planning authorities (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications).

Following this advice:
- avoids the need for you to consult on the impacts of planning applications on hazel dormice in most cases
- can help you make decisions on development proposals
You may need a qualified ecologist to advise you on the planning application and supporting evidence. You can find one using either the:
- Chartered Institute of Ecology and Environment Management (CIEEM) directory (https://cieem.net/i-need/finding-a-consultant/)
- Environmental Data Services directory (https://www.endsdirectory.com/)
Qualified ecologists should read the Hazel Dormouse Mitigation Handbook and the Hazel Dormouse Conservation Handbook, third edition.

How hazel dormice are protected

Hazel dormice are a European protected species protected under the Conservation of Habitats and Species Regulations 2017.

It is an offence to:
- deliberately kill, injure, disturb or capture them
- damage or destroy their breeding sites and resting places (including when hazel dormice are not present)
- possess, control or transport them (or any part, alive or dead)
- sell, exchange or offer for sale or exchange
It is also an offence under the Wildlife and Countryside Act 1981 to intentionally or recklessly:
- disturb them while they occupy a structure or place used for shelter or protection
- obstruct access to a place used for shelter or protection
- possess or transport them (or any part, alive or dead)
- sell, offer or publish an advert to sell them
Hazel dormice are included on the list of species of principal importance in England (https://www.gov.uk/government/publications/habitats-and-species-of-principal-importance-in-england) under section 41 of the Natural Environment and Rural Communities Act (2006). They are also listed as vulnerable on the Red List for England’s Mammals, on the Mammal Society website (https://mammal.org.uk/current-research/red-list-for-britains-mammals?rq=red%20list). You must consider the conservation of hazel dormice as part of your planning decision. Find out more about your biodiversity duty (https://www.gov.uk/guidance/complying-with-the-biodiversity-duty).

The developer must comply with the legal protection of hazel dormice.

The developer may need a hazel dormice mitigation licence (https://www.gov.uk/government/publications/hazel-dormice-apply-for-a-mitigation-licence) to carry out their development proposal.

When to ask for a survey

You should ask for a survey if either of these apply:
- distribution and historical records suggest hazel dormice may be present – you can search the National Biodiversity Network Atlas (https://nbnatlas.org/) by species and location
- the development proposal will affect an area of woodland (including deciduous, conifer or mixed woodland), hedgerow or scrub
Absence of a record does not mean there are no hazel dormice. It could mean there is no survey data available for that location.

Surveys need to show whether hazel dormice are present in the area or nearby, and how they use the development site.

Survey work can include:
- visual searches for nests and opened hazelnuts - for smaller projects, such as creating gaps in hedgerows or removing a small amount of bramble scrub
- using nest tubes or boxes, or footprint tracking tunnels – for more damaging projects or licence applications
If hazel dormice are found on part of the development site, you can assume they’re present in suitable habitats on the whole development site.

Unless the development proposal will have a low impact on hazel dormice, the survey should also include an assessment of the development site’s importance. Factors to consider include:
- the presence of other hazel dormouse populations in the area
- whether hazel dormice are widespread or limited to a few sites
- the known range of the hazel dormouse
- habitat composition - this should include tree and shrub species present and habitat structure
- how and how well habitats are connected
- predicted hazel dormouse population numbers based on habitats present
The survey should be from the current or previous active season. Surveys up to 3 years old are acceptable if the habitats have not significantly changed.

You must check if the ecologist is qualified and experienced to carry out surveys for hazel dormice (https://www.gov.uk/government/collections/dormice-licences#hazel-dormice-survey-licences). CIEEM publishes:
- competencies required for species surveys (https://cieem.net/resource/competencies-for-species-survey-css/)
- advice on the valid age of ecological reports and surveys (https://cieem.net/wp-content/uploads/2019/04/Advice-Note.pdf)
These documents may not be accessible to assistive technology.

Assess the effect of development on hazel dormice

Developers should submit information with their planning application on how their development proposal avoids or mitigates harm to hazel dormice.

Activities can harm hazel dormice if developers:
- handle them
- disturb them, for example from noise and using light or woodland and hedgerow management
- remove habitat, such as clearing woodland for a new road causing habitat fragmentation and isolating dormice populations
- remove foraging habitat
- remove or change habitats in a way that affects the hazel dormouse population and increases the risk of death
- remove hedges or other linear habitat that links populations
Post-development effects could include increased:
- disturbance from people, for example from a new housing development
- risk from predators like domestic cats introduced by new homeowners
Avoidance, mitigation and compensation measures

Where possible development proposals should avoid negative effects on hazel dormice. Where this is not possible, the developer will need to include adequate mitigation or, as a last resort, compensation measures in their development proposal to allow you to make a planning decision.

To avoid possible negative effects on hazel dormice, developers could redesign the development proposal to:
- leave dormice habitat in place
- alter the timing of works
- change the methods of working
Where this is not possible, mitigation and compensation measures could include:
- improving existing habitat, for example tree thinning, coppicing and new planting
- creating new habitat by planting new areas
- installing dormouse nest boxes in places where interference by humans and domestic cats can be avoided
- creating links to other habitats, for example green bridges across gaps in habitat of less than 100 metres (usually over roads or railway tracks)
Mitigation measures could also include coaxing the hazel dormice to a nearby location by clearing small sections of neighbouring habitat. All remaining habitat must either be large enough to support a hazel dormouse population, or be linked to other areas of habitat. Hazel dormice should not be left in small, isolated areas.

If there is no reasonable alternative habitat close by, the mitigation proposal could include capturing hazel dormice and moving them to a different location, known as translocation. Natural England will only grant a licence to translocate hazel dormice as a last resort as they can become stressed easily. A specialist managing translocation should be familiar with:
- Reintroductions and conservation translocations in England (https://www.gov.uk/government/publications/reintroductions-and-conservation-translocations-in-england-code-guidance-and-forms)
- the IUCN Guidelines for Reintroductions and Other Conservation Translocations
- the Hazel Dormouse Mitigation Handbook and the Hazel Dormouse Conservation Handbook, third edition
Measures should be taken to reduce hazel dormice’s stress, most importantly by feeding them natural food and releasing them in groups in late summer or early autumn The new habitat must be capable of supporting the hazel dormice. The proposal should include evidence that translocation would benefit hazel dormice conservation.

If translocating hazel dormice, the proposal will need a suitable receptor site. The new receptor site should:
- not have a hazel dormouse population already
- be ready before translocation takes place
- be large enough to support an expanding hazel dormouse population
- be connected to other areas of habitat within the wider landscape
- ideally have a diverse structure and species of plants suitable for hazel dormice
For more information on mitigation plans and compensation measures, read section 3 of protected species and development: advice for local planning authorities (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications#agree-avoidance-mitigation-or-compensation-measures).

Planning and licence conditions

The developer may need to apply for a hazel dormice mitigation licence (https://www.gov.uk/government/publications/hazel-dormice-apply-for-a-mitigation-licence) if their activities are likely to affect hazel dormice. You may also need to add mitigation or compensation strategies as a condition of planning permission.

Before you can grant planning permission, you must:
- work with the relevant ecologist to make sure these conditions do not conflict with the requirements of the hazel dormice licence
- be confident that Natural England will issue a licence – read section 4 of Protected species and development: advice for local planning authorities (https://www.gov.uk/guidance/protected-species-how-to-review-planning-applications#consider-if-a-licence-is-likely-to-be-granted-before-you-give-permission)
You do not need to consult Natural England on the wording or discharge (approval) of any conditions you impose on a development proposal. Natural England is unable to provide advice on this.

Natural England will not generally issue a licence until planning conditions relating to protected species have been discharged. This applies to conditions that are intended to be and capable of being discharged before development begins.

Natural England will only confirm if you need a licence when the development proposal is a Nationally Significant Infrastructure Project (NSIP).

Enhance biodiversity

To meet your biodiversity duty (https://www.gov.uk/guidance/biodiversity-duty-public-authority-duty-to-have-regard-to-conserving-biodiversity), you should suggest ways for the developer to:
- create new or enhanced habitats on the development site
- achieve improvements in biodiversity through good design
- follow other relevant plans and strategies for nature
Site management and monitoring

You should consider the need for site monitoring and management. These measures are likely to be needed by protected species licences.

A site management and monitoring plan should include:
- monitoring the status of the hazel dormouse population before, during and after construction
- managing vegetation
- checking the availability of foraging and nesting habitats
- monitoring how effective the mitigation or compensation strategy is, for example by checking nest boxes as part of the National Dormouse Monitoring Programme – remedial work should follow if needed
The site should be monitored for long enough to determine the success of the measures proposed, and take remedial action when necessary. The site management and monitoring plan should make clear who is responsible for each action.