Dormouse surveys may be needed if potentially suitable habitat such as woodland, hedgerow and scrub, is present on a site, particularly within the known range of dormice. Dormice are protected by the Conservation of Habitats and Species Regulations (2017), Natural Environment and Rural Communities Act (2006) and the Wildlife and Countryside Act (1981). It is an offence to kill them, capture or disturb them, or damage their habitat.
What is a dormouse?
Dormice are small nocturnal mammals with golden fur and a pale underside, and unlike other small British mammals they have a long furry tail. The dormouse is a protected and threatened species with population numbers falling dramatically due to habitat loss.
Why would a dormouse survey be required?
If there are records of dormice close by or if a development site has suitable habitat (typically woodland, scrub or hedgerows), it will be necessary to determine if dormice are present before submitting your planning application.
Mitigation licences from Natural England are required for all works which could impact on dormice or their resting or breeding places.
What are dormouse surveys?
Dormouse surveys can either take the form of nut searching or nest tube/box surveys.
Nut searching can be undertaken where there is sufficient fruiting hazel and involves searching for distinctively nibbled dormouse hazel nuts. This method can be used if only small areas of habitat will be lost. Nut searching can be carried out all year round but are best undertaken between September and December.
For larger projects or if a nut search proves inconclusive, it will be necessary to undertake a nest tube/nest box survey. This survey method involves placing nest tubes (small plastic tubes with wooden trays) or nest boxes within suitable habitat over several months and checking them for the presence of dormouse nests. Usually nest tubes are used with nest boxes usually being deployed for monitoring purposes.
It is necessary to usually deploy a minimum of 50 nest tubes between April and November and check them regularly (at least every other month) to achieve an adequate ‘thoroughness’ score which is dependent on how many tubes are used, and over how many months they are deployed.
What happens if dormice are found?
If surveys confirm dormice are present and it is not possible to avoid impacting on them or their habitat, it will be necessary to implement appropriate mitigation under a European Protected Species Mitigation licence which is issued by Natural England.
Licensed mitigation could include:
- Undertake sympathetic and staged habitat clearance (less than 50m blocks) by hand which persuades the dormice to relocate into adjoining suitable habitat
- For larger impacts (loss of 1/1.5 hectares of woodland or 300m of hedgerow), sensitive clearance during winter which encourages dormice to move into adjacent habitat when they come out of hibernation in May.
- Translocation of individuals through the use of dormouse boxes.
Our services
If you think your project may require dormouse assessments or surveys, Deepdene Ecology will be able to help you out by providing advice and licensed surveyors.
Deepdene Ecology Ltd 