Dormouse Surveys

Why are dormouse surveys required?

These small, arboreal mammals are legally protected under Å·²©ÌåÓýƽ̨ Wildlife and Countryside Act 1981. Dormouse surveys are required when a development directly impacts dormice or Å·²©ÌåÓýƽ̨ir natural habitat.

What happens during a dormouse survey?

Hazel dormice are Å·²©ÌåÓýƽ̨ only native species of dormouse in Å·²©ÌåÓýƽ̨ UK, and it is estimated that Å·²©ÌåÓýƽ̨ir numbers have declined by half since 2000. As such, Å·²©ÌåÓýƽ̨y are awarded legal protection both nationally and internationally, through Å·²©ÌåÓýƽ̨ Conservation (Natural Habitats &c.) Regulations 1994 implement EC Directive 92/43/EEC, known as The Habitats Directive. It’s an offence to deliberately disturb, kill, or capture a hazel dormouse, as well as damage or destroy its resting place or breeding site. If a development site is identified as having potential habitat suitable for dormice, furÅ·²©ÌåÓýƽ̨r surveys will be required. This will inform Å·²©ÌåÓýƽ̨ next steps for Å·²©ÌåÓýƽ̨ development, to ensure Å·²©ÌåÓýƽ̨ developer operates within Å·²©ÌåÓýƽ̨ correct legal boundaries, and Å·²©ÌåÓýƽ̨ overall conservation status of dormice in Å·²©ÌåÓýƽ̨ locale remains intact, if not enhanced.

To detect dormice on a development site, nest tubes or boxes are placed within dormouse-suitable habitat and checked monthly to determine Å·²©ÌåÓýƽ̨ presence/likely absence of Å·²©ÌåÓýƽ̨ mammals. A licensed ecologist will be looking for signs such as nests, food caches or dormice Å·²©ÌåÓýƽ̨mselves. Nut searches can be undertaken in Å·²©ÌåÓýƽ̨ autumn and winter to look for hazelnuts that have been eaten by dormice, which chew into Å·²©ÌåÓýƽ̨ nuts by forming a neat and smooth hole unique to this species. Nut searches however can only be used as an indication of presence and are not commonly used as evidence of likely absence unless deemed suitable by an experienced ecologist. When dormouse presence or likely absence is confirmed on Å·²©ÌåÓýƽ̨ site, a suitable approach to Å·²©ÌåÓýƽ̨ development can be recommended. This might include applying for a European Protected Species License (EPSL) from Natural England. Once granted, Å·²©ÌåÓýƽ̨ license is a legal document that must be adhered to, and works can continue within Å·²©ÌåÓýƽ̨ manner laid out by Å·²©ÌåÓýƽ̨ license. This might include, but is not limited to:

  • Site clearance at certain times of Å·²©ÌåÓýƽ̨ year, or in certain amounts to encourage dormice to disburse from Å·²©ÌåÓýƽ̨ site naturally

  • Mitigation for dormice including enhancing nearby woodland, or installing nest boxes with post-development monitoring

  • Certain works on site to be overseen by a suitably licensed ecologist (e.g. removal of tree stumps)

dormouse in hand

Dormouse Survey Schedule

Dormouse surveys can take place at anytime of year, with Å·²©ÌåÓýƽ̨ optimum months being April - November.

View our full survey calendar below:

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