It’s the season for reptile and dormouse surveys

It’s the season for reptile and dormouse surveys
Any development work carries a risk of disturbing a protected species. If you think there may be dormice or reptiles on the land you are planning to work on, there are extra steps you need to take to protect the habitat.

The Hazel Dormouse

The Hazel, or Common, Dormouse is at a serious risk of extinction – numbers have dropped by at least 50% over the last century due to the loss and fragmentation of their natural woodland habitat and the impact of human activity such as agriculture and urbanisation.

If you are aware of any information that suggests there may be dormice present, or if the land contains woodlands, scrub or hedgerows which are a suitable habitat for dormice, you will need to carry out surveys in order to gain planning consent.

Dormouse Nesting Tubes

Using nesting tubes is a reliable way of checking for the presence of dormice. A minimum of 50 tubes need to be put in place during April or May and left there for the season so they can be checked every two months. The tubes are ideal for dormice to make their summer nests in.

Surveyors use a table to calculate an Index Score, which determines if the scale of the survey is sufficient to adequately determine the presence or absence of dormice. It’s based on a calculation of 50 nesting tubes being placed around 15 or 20 metres apart across the site.

It’s illegal to disturb an area where dormice may be present, and the mere act of carrying out a survey may necessitate moving nests and disturbing dormice. Therefore, your licenced surveyor will have to apply for a special licence giving permission to search for dormice in a specified area.

Other ways to survey for dormice

Other methods of surveying include placing nest boxes around the site and checking open hazelnuts. Nest boxes don’t count in official survey figures, but can provide extra information and can be useful for the long-term surveillance of the creatures.

Dormice have a specific bite pattern, which means a surveyor can tell if they’re the ones responsible for any open hazelnuts found on the ground between September and December – dormice will leave a smooth, round hole in the shell, whereas other rodents will leave visible toothmarks. Finding these nuts can prove there are dormice in the area, but a lack of these marks can’t be used to prove there are no dormice present.

Reptiles in the UK

The six native reptile species in the UK are also protected by law, and surprisingly similar techniques to those used to check for dormice are used to gauge reptile numbers ahead of any planning applications.

They are commonly found in woodland with open patches for basking, and close cover for shelter.

The species to look out for are:

  • Adder
  • Common lizard
  • Grass snake
  • Sand lizard
  • Slow worm
  • Smooth snake

A simple walk of the site may be enough for an ecological specialist to determine the presence, or likely presence, of reptiles and the need for a survey.

As with dormice, it’s illegal to damage or disturb anywhere that may be a suitable habitat for these reptiles, and harming one can carry a fine of up to £5,000 per offence.

Carrying out a reptile survey

Artificial refuges for the reptiles are placed around the site. Instead of a tube, the shelters are normally made of corrugated metal or roofing felt which warms up and provides an ideal resting or basking spot for reptiles.

The shelters need to be checked at least 7 times, ideally in April, May or September, when the weather is warm, but not too warm. If the surveys are conducted in the hotter months, more checks will be needed. Snakes and slow worms will normally be found underneath the shelters, while lizards enjoy basking on top.

The requirements for reptile surveys are very specific and should only be carried out by a licenced surveyor. Like the artificial dormouse nesting holes, creating reptile refuges necessarily creates a disturbance to the habitat, and can carry penalties if not carried out with the appropriate licences and consents.

Results of a dormouse or reptile survey

Once the surveys are complete, your specialist ecologist will be able to look at the results to determine if a protected species is in the area and indicate the population size.

These results can be compiled into a report suitable to be presented as part of a planning application, along with suggestions of possible mitigations if they’re needed. This may include measures such as changing the proposed layout, changing vegetation to discourage them from certain areas or even moving the creatures if no other measures are appropriate.

By working with a specialist ecologist, you can be sure that protected species are spotted at the earliest possible opportunity, allowing for surveys, reports and mitigation measures to be arranged before they have a significant impact on your development.

For more advice about identifying protected species, arranging surveys or tailored mitigation measures for your development, get in touch with us on 01225 459564 or email

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