Services · Core

Dormouse Surveys

The hazel dormouse is a European Protected Species and a key indicator of high-quality hedgerow and woodland habitat. If your development affects hedgerows, woodland or scrub with dormouse potential, surveys are likely to be required.

Survey seasonApril – November

Minimum effortNest tubes, monthly checks

ProtectionEuropean Protected Species

Key habitatHedgerows & woodland

Overview

The hazel dormouse (Muscardinus avellanarius) is one of Britain's most elusive mammals and a European Protected Species under the Conservation of Habitats and Species Regulations 2017. Dormice are associated with species-rich hedgerows, deciduous woodland, coppice and dense scrub — habitats that provide the continuous canopy connectivity they depend on for movement, foraging and nesting.

Dormouse surveys use nest tubes or footprint tunnels deployed across suitable habitat and checked monthly from April to November. The survey effort is designed to achieve a minimum probability of detection — typically requiring tubes to be in place for the full season, with a minimum of five monthly checks. Nest tubes provide evidence of presence through characteristic nests; footprint tunnels detect dormice via their distinctive footprints on ink tracking papers.

Where dormice are confirmed and the development will result in habitat loss or fragmentation, a European Protected Species Mitigation Licence from Natural England is required. We design mitigation strategies including habitat creation, translocation where necessary, and long-term management plans to maintain habitat connectivity.

When you need this

Your development will remove, fragment or significantly disturb hedgerows or woodland with dormouse potential
Your PEA identifies suitable dormouse habitat — species-rich hedgerows, deciduous woodland, hazel coppice or dense scrub
Biological records show dormice in the local area or the site falls within known dormouse range
The LPA or Natural England requests dormouse survey as a condition of planning
Road schemes, railway works or utility corridors will sever hedgerow or woodland connectivity

Our approach

01
Habitat assessment
A walkover to assess the suitability of hedgerows, woodland and scrub for dormice — species composition, structural diversity, canopy connectivity and the availability of food sources across the season.
02
Nest tube / footprint tunnel deployment
Nest tubes or footprint tunnels are installed at appropriate density across suitable habitat, typically 50 tubes per area of habitat, and left in place for the survey season.
03
Monthly checks (April–November)
Tubes or tunnels are checked monthly by a licensed surveyor. Dormouse nests are distinctive — tightly woven balls of grass and honeysuckle bark — and readily distinguished from bird or wood mouse nests.
04
Impact assessment and licensing
Where dormice are confirmed and habitat will be lost, we assess the impact, design mitigation (habitat creation, enhanced connectivity, translocation) and prepare the EPS Mitigation Licence application to Natural England.

Survey season

April–November

Optimal: May–September

Nest tubes must be in place for a minimum survey period to achieve adequate detection probability. The optimal months are May to September when dormice are most active and nest-building is at its peak. Surveys outside this window have lower detection rates. A full season of survey (April–November) is standard practice.

Regulatory context

Conservation of Habitats and Species Regulations 2017Hazel dormouse is listed on Schedule 2 as a European Protected Species. It is an offence to deliberately capture, kill or disturb dormice, or to damage or destroy a breeding site or resting place without a licence.
Wildlife and Countryside Act 1981Dormice are listed on Schedule 5, providing additional protection against disturbance, obstruction of access to shelter and sale.
NERC Act 2006 (Section 41)Hazel dormouse is listed as a Species of Principal Importance in England, placing a duty on public bodies to have regard for its conservation.

Related services

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Frequently asked questions

01How long does a dormouse survey take?+

Nest tubes need to be in place for a minimum of five months with monthly checks to achieve adequate detection probability. A full April–November survey season is standard. This means dormouse surveys require early planning — commissioning late in the season may mean waiting until the following spring.

02What happens if dormice are found on my site?+

Development can proceed with appropriate mitigation under a European Protected Species licence from Natural England. Mitigation typically involves habitat creation or enhancement to compensate for losses, maintenance of hedgerow connectivity, and potentially translocation of dormice from the affected area under licence.

03Are dormice common in Sussex?+

Sussex falls within the core range of the hazel dormouse in southern England. They are present in many hedgerow networks and woodland areas across the county, though their elusive nature means they are often under-recorded. Any development affecting suitable habitat in Sussex should consider dormouse survey.

04What is a nest tube?+

A nest tube is a small open-ended wooden or plastic tube placed in hedgerows or woodland. Dormice enter the tube and build characteristic nests inside — tightly woven balls of grass, leaves and stripped honeysuckle bark. Monthly checks by a licensed surveyor detect these nests as evidence of dormouse presence.

Get in touch

Have a site that needs surveying?

Tell us about the project. We'll come back with a clear scope, timing and a fixed quote.

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