Don’t hang around, get your bat surveys organised now

Bats are a protected species across the UK and Europe, so if you’re planning to do any work that might disturb them, their breeding sites or resting places, you need to be sure how many bats there are and of what species before doing anything.

If you’re planning any work, you will need to commission a bat survey – as whether it’s stated outright in your planning consent or not, it’s a legal requirement to make sure your project won’t affect any bats.

It’s the duty of every planning authority to consider whether it’s likely that your proposals will have an impact on bats, and they need detailed and robust evidence about how bats use your site, and what measures you will be taking to mitigate any impact on them.

Why is it so important to look after bats?

On a personal level, if you don’t take the necessary steps to look after bats, you could be facing six months in jail and unlimited fines. To avoid this, taking on an environmental consultant to assist from the earliest stages of planning will ensure you have the accurate and up-to-date knowledge you need. With different planning requirements in each country of the UK, this knowledge is even more important.

Environmentally, bats play a crucial role in many habitats, pollinating flowers and controlling pests. Bats are also ‘indicator species’ in some areas, acting as a signal about the health of the wider habitat – if bat numbers start to decline, it can be a sign that other species are struggling or that the local habitat is being poorly managed.

Bats can be so integral to the success of a habitat that they’ve even been known to reintroduce plants to areas which have previously been cleared. They are a unique means of seed dispersal which wouldn’t be possible without them.

How is a bat survey carried out?

Any bat survey needs to be carried out by a licensed bat surveyor. Their expertise will help in analysing both your site and the area around it, looking to ensure your project won’t disturb any roosting spots, or the bats’ ability to breed or look after their young.

Bats are experts in concealing their presence, so even if you don’t think there are any signs of bats, it’s worth arranging for a survey to be carried out. It’s likely that a survey will be called on in the process of gaining consent, and any surveys carried out more than 2 years ago will be deemed unreliable as roosts move around frequently.

The first part of the survey is the Preliminary Roost Assessment, which can be done at any time of the year. This is a visual assessment of a building or structure, looking for spaces where bats could be living or roosting. Potential sites and features include:

  • Easy access and clear flying space
  • Large roofs
  • Cavity walls
  • Disused mine shafts or underground cellars
  • Places near woodland or water
  • Stone buildings
  • Tree roots

If a visual check isn’t possible but is a good potential site for bat roosts, such as old buildings with cracks and holes, or large amounts of ivy covering mature trees, the areas can be marked as ‘potential’ and listed for further investigation if necessary.

Monitoring and Field Surveys

If the Preliminary Roost Assessments show that bats are likely to be present, an experienced bat surveyor will need to carry out field surveys.

These surveys can only be carried out between May and September, as this is when bats are looking to breed, and there’s a massive increase in the level of activities around roosts. This makes it much easier to see how many bats there are in an area, and what species they are – critical information in assessing the impact development work may have on the bat population.

The signs of bats can be found during daylight hours, so surveyors will look for evidence such as bat droppings roosts and other signs. They may also use some or all of the following methods or techniques:

  • Infrared cameras
  • Listening stations
  • Hand-held detectors
  • Fixed detectors
  • Radio tagging
  • Trapping

As bats are nocturnal, several dusk and dawn surveys may be needed to get a clear picture of the bats’ behaviour. Surveyors will need to have a good idea of how many bats of various species are present, and there are strict guidelines detailing the number of surveys required to produce the solid evidence needed in support of a planning application.

If it’s discovered that there is no way to avoid an impact on the bats, a surveyor can also do an emergence/re-entry survey, which records how many bats there are, where they enter and exit a structure, the route they take and when they take it. This gives a much more detailed record of the bat activity.

What steps need to be taken if bats are present?

In order to protect bats as much as possible, developers are expected to alter their projects as far as possible to avoid disturbing them.

If your plans cannot be adapted to avoid disturbing a bat population, there are mitigation and compensation schemes which can be presented as a potential solution. This could include re-siting the development, creating new roosts or providing long-term provision to look after the bat habitat.

Any work that involves demolition or land clearance obviously risks destroying a habitat, which could negatively impact on bats. Therefore, any work of this kind is likely to need a European Protected Species Licence to permit you to do the work.  To get this licence, a licenced bat specialist will need to give advice and produce and submit your licence application. The licensing and planning processes are legally entirely separate processes.

But even if you’re not carrying out demolition or clearance, there are other impacts you should think about:

  • Human activity during and after the work
  • Increased noise and light levels near roosts and around flight paths
  • Temperature and humidity changes
  • Changes to entrances and exits

By working with an environmental expert, you can make sure the results of the bat survey are incorporated into your planning application, along with any mitigation plans.  Environmental experts will also be experienced in working alongside architects and building contractors before and during the work, and checking the site once work is complete to monitor any changes among the bat population.

To make sure your bat survey is carried out within that critical May-September window, or of you need any other help or advice regarding bats in or around your development, contact us on 01225 459564 or email

Get in touch

To discuss your project requirements, please contact our experienced team