Hazel Dormouse Survey

If you are planning a development project that could impact an area of woodland, hedgerow or scrub, a survey for hazel dormouse may be required for your development or planning application to proceed.

EBD expertise.

We are experienced in planning and delivering field surveys for dormouse on a range of sites to assess their presence or likely absence in order to advise on appropriate mitigation strategies to be considered within the project design and schedule. Where impacts cannot be avoided, a mitigation licence will need to be obtained from Natural England.

Why and when do you need a hazel dormouse survey?

Hazel dormice populations have declined by 70% in the UK since 2000 due to habitat loss, degradation and poor management of woodlands and hedgerows, compounded by a changing climate. They are a protected under UK wildlife legislation, and in England and Wales it is illegal to:

Intentionally or deliberately capture, kill, or injure them;
Intentionally or recklessly damage, destroy, and disturb them in a place used for shelter or protection, or obstruct access to such areas;
Damage or destroy a breeding site or resting place of a hazel dormouse;
Possess a dormouse, or any part of it, unless acquired lawfully; and
Sell, barter, exchange, transport, or offer for sale a dormouse or parts of them.

If there is a risk of encountering hazel dormice at your site, for example if your site supports suitable habitats and is located within the known distribution for dormice in the UK, then a survey will be required.

The usual ‘trigger’ for a hazel dormouse survey requirement is a request from your planning consultant, architect or the local planning authority so that a report can be submitted with a planning application. Surveys may also be recommended as the result of an ecological scoping survey or preliminary ecological appraisal.

What does a hazel dormouse entail?

The presence of suitable hazel dormouse habitat is often established via ecological scoping or a preliminary ecological appraisal. Presence (or likely absence) of dormice can be established via several methods:

Nut searches: an efficient method to establish the presence of dormice is to search for gnawed hazel nuts, as dormice leave distinctive openings in hazelnuts when gnawing them. Nut searches can be conducted in areas with suitable dormice habitat.
Nest tube surveys: Nest tubes (plastic tubes with wooden inserts) secured to woody vegetation, are deployed in suitable habitats, and monthly checks are undertaken to establish presence of dormice and their distinctive woven nests.
Footprint tunnel surveys: Footprint tunnels (modified nest tubes) with tracking ink deployed in suitable habitat for a minimum of 3 months; and checked twice a month for characteristic dormice footprints.

Supplementary survey methods include the use of wooden nest boxes (particularly for small sites or for longterm monitoring), natural nest searches, eDNA and trail cameras.

Hazel Dormouse Calendar - best time of year:

Assessment of habitat suitability for dormice can be undertaken at any time of year. Dormouse presence/likely absence surveys can take several months between April and November, although nut searches can be conducted between September and February.