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Call the Bat Conservation Trust Helpline on 0845 1300 228.

Bats are one of the most frequently encountered wild animals in development.

Wales is home to 16 bat species occupying several habitats, with occasional, maternity and hibernation roosts. Of these 16 species, up to 10 are regularly recorded in Bridgend County Borough. Bats are protected by:

As such, damaging or blocking a bat roost or shelter whether or not bats are present, or killing, injuring or disturbing bats is illegal.

Note to homeowners

Bats are important for our environment. As insectivores, they control pests, and eat thousands of insects every night. Worryingly, bats numbers in the UK have reduced significantly over the last hundred years. This is partly due to the decline in suitable places for roosting and partly because of greater pesticide use. This reduces the number of insects and harms bats too.

There are plenty of ways you can help the bat population such as planting a bat-friendly garden or putting up a bat-box. Find out more at the Bat Conservation Trust.

Development advice

National planning policy states it is essential that protected species’ presence and whether developments may affect them is established before planning permission is given. Otherwise, the decision won’t address the most important factors.

Consequently, the local authority must have enough information to exclude any impact of the development on protected species before making its decision. As with other surveys’ planning requirements, it is the applicant’s responsibility to provide this information.

Bats roost in numerous locations including buildings, structures, trees and woodland. It is vital to avoid damaging or disturbing a roost during and after development.

Whether a bat survey is needed

It isn’t always essential. Not all buildings have bats, but, we don’t know where all the bats are. Like many animals, bats prefer to use certain buildings close or linked to habitats they like. We use guidance from the Bat Conservation Trust’s Good Practice Guidelines (2012) to help us identify which developments are most likely to encounter bats.

Please note that when it is deemed unreasonable to request a survey, it doesn’t mean that bats won’t be present. If bats are found during development, remember that they are still a protected species, and it is an offence to disturb them. Please refer to the bat warning below for further information.

Due to continued loss of habitat, bats have had to shelter in many of our buildings or trees in our gardens to survive. Often you will be unaware of them. But don’t worry, as they won’t do any harm.

The following information is to help you identify whether your development could affect bats, which would mean your application may need a bat survey.

Guidance note 1:

We will need a suitably experienced, qualified ecologist to run a bat survey if your development proposals involve:

  • conversion, modification, demolition or removal of any building including derelict buildings which are:
    • agricultural buildings such as farmhouses, barns and outbuildings of traditional brick or stone construction and/or with exposed wooden beams
    • buildings with weather boarding and/or hanging tiles that are within 200m of woodland and/or water
    • pre-1960 detached buildings and structures within 200m of woodland and/or water
    • pre-1914 buildings within 400m of woodland and/or water
    • pre-1914 buildings with gable ends and/or slate roofs, regardless of location
    • located within, or immediately adjacent to woodland and/or immediately adjacent to water
    • Dutch barns or livestock buildings with single skin rooves and board-and-gap or Yorkshire boarding if a preliminary roost assessment finds it particularly bats friendly
  • affecting built structures like:
    • tunnels, mines, kilns, ice-houses, adits, military fortifications, air-raid shelters, cellars and similar underground ducts and structures, unlined and unused industrial chimneys constructed in brick/stone
    • bridge structures, aqueducts and viaducts especially over water and wet ground
  • lighting of:
    • churches, listed buildings, green space such as sports pitches within 50m of woodland, field hedgerows or lines of trees with connectivity to woodland or water
    • any building previously listed
  • felling, removal or lopping of:-
    • woodland
    • field hedgerows and/or lines of trees with connectivity to woodland or water bodies
    • old and veteran trees that are over 100 years old
    • mature trees with obvious holes, cracks, cavities or which are covered with mature ivy including large dead trees
  • proposals affecting water bodies
    • in or within 200m of rivers, streams, canals, lakes, reedbeds or other aquatic habitats
  • proposals located in or immediately adjacent to
    • quarries or gravel pits
    • natural cliff faces and rock outcrops with crevices, or caves, and sink-holes
  • proposals for wind farms of multiple or single turbines depending on size and location with small domestic turbines needing to be considered site by site
  • all proposals in sites where bats are known to be present

If your development meets any of the above criteria, please see Guidance Sheet B9’s Ecological Survey requirements for further guidance on bat surveys.

Whether or not your development requires a survey please see the new benefits section below. All development creates an opportunity to enhance biodiversity and by incorporating simple measures into the development, you can help contribute to the population. You may get some of the surprising benefits of encouraging these mammals into your gardens.

All bat species and their breeding sites or roosts have full legal protection under:

Without a licence, bats have legal protection from anyone intentionally:

  • killing
  • injuring
  • handling
  • possessing, whether live or dead
  • disturbing while roosting
  • selling or offering a bat for sale

It is also an offence to damage, destroy or obstruct access to any place used by bats for shelter, whether they are present or not.

It is extremely important that developers and landowners contemplating activities that may affect bats get site-specific advice before making designs or programmes.

Activities that may result in the above offences can be permitted occasionally. However, a strict process of licensing must be observed and followed for it to be lawful.

If the proposed activity requires planning consent or any other type of consent such as listed building consent or extraction licences, it must be in place. Also, it should be provided to Natural Resources Wales (NRW) with the licence application.

A licence is often needed from NRW to run development and vegetation clearance works that may affect bats and any other European protected species. That is regardless of whether those works need planning permission. Failing to get a licence before starting development or site clearance could result in offences being committed. This could lead to delay, prosecution, fines, confiscation of equipment, legal fees and, potentially, a custodial sentence.

Licences are granted under the Habitats Regulations provisions. To grant a licence, NRW must be satisfied the proposed activity meets the Habitats Regulations’ criteria, which are often referred to as “the three tests”.

The three tests

These tests include:

  • the need for the proposed development/activity
  • consideration of possible alternatives by activity, method, timing, phasing, location
  • maintaining the favourable conservation status of the bat population to be affected

Similarly, the Habitats Regulations require us to consider the proposed development’s effect on bats before determining planning applications that could affect them or their habitats. Thus, we must also be satisfied that the proposals will meet the tests’ criteria in order to grant planning consent. This duty applies whether the application is for outline, reserved matters or full planning.

To help us and the NRW assess proposals, the developer or landowner must give enough information to make a decision against the Habitats Regulations including:

  • up to date presence/absence survey data
  • a population estimate, if present
  • a habitat assessment
  • an impact assessment
  • a mitigation and compensation strategy
  • a management and monitoring plan


For each offence, the maximum penalty for non-compliance with the above laws is a £5000 fine and/or six months imprisonment. Any equipment used to commit the offence may be forfeited. Both the company and individuals can be held liable.

When surveying the site and/or parts of it for bats, you should consider the timing of surveys. Different types of bat survey are run at different times of the year and this could affect your development schedule. It is important you are clear at what time these will be taking place.

The survey effort will vary depending on the site’s location, its character, level of impact and the species potentially affected.

The most common survey requested from household developments is an initial bat survey and report. This survey involves a habitat assessment and inspection of the building/potential roost which can be made at any time of year. It may be enough to submit the bat survey report for planning permission if no risk to bats is considered to exist.

Guidance note two:

We will only accept survey/assessment work which a suitably qualified person has done by the recognised survey guidelines.

All survey/assessment work must be run and prepared by competent persons with suitable qualifications, licenses and experience. Survey work must be done at appropriate times and months of the year, in suitable weather conditions and using nationally recognised survey guidelines/methods where available. It must also be done to best practice standards. For guidance, visit ‘sources for survey methods’.

Reports should also include detailed information on impact assessment and include any necessary measures for avoidance, mitigation, compensation and enhancement. Further guidance on bat surveys and mitigation for development for structures like buildings or wind turbines can be found on Natural England’s website. Also see the Bat Conservation Trust, and Bat Surveys Good Practice Guidelines.

Guidance note three:

Developers/applicants must give enough evidence to show that avoidance is impossible before mitigation or compensation are considered viable alternatives.

Once the bats’ extent is known, you can take steps to avoid disturbing them. This could simply be retaining the roost location and/or foraging/commuting habitat in your plan. Timing of development or preparing for development activities is equally important. Most roosts are seasonal, as with breeding roosts in spring/summer and hibernation roosts in winter. This pattern gives windows of opportunity to do works during periods when roosts aren’t in use.

Importantly, a roost is protected regardless of whether bats are present during works or not. Thus it is important to seek professional advice to assist your scheme.

Avoidance measures are designed to avoid adverse effects of change. Examples include locating a development away from areas of ecological interest, and the Technical Advice Note 5 (TAN 5) has more information on this.

Professional ecologists can help you identify possible effects on bats and identify how to avoid harm including identifying potential issues you may not think of. For example, lighting schemes can have adverse effects on wildlife including bats. Identifying this early for inclusion into the development provides opportunity to avoid harming protected species by providing dark corridors for movement like unlit cycle paths. It may flag the need for additional surveys and licenses, while also reducing a development’s light pollution.

Incorporating landscape features into the development’s design/master plan will help avoid harm to bats. It should also be considered for the many green infrastructure benefits, and contribution to related policies and requirements.

Maintaining hedgerows can help contribute to the landscape character (SP2, SP4 and ENV3) while also maintaining bats’ flight paths. Trees and hedgerows have several benefits and developments should incorporate these features.

If disturbance of protected species or habitat is unavoidable, a suitable mitigation scheme will need to be agreed. If evidence of bats has been found, avoidance has been ruled out. Where harm is unavoidable then the loss of a roost/disturbance to bats will have to be mitigated for. If there is a need to mitigate for protected species during activities like demolition, building renovation, or felling trees, an NRW licence will be needed. The type of mitigation/avoidance measures like timing of works included in the licence application will depend on the bat species and roost type.

Guidance note four:

Where harm is unavoidable, mitigation measures should minimise it. The bat consultant undertaking the survey can guide you through the licence application process.

Where avoidance is impossible, mitigation can enhance the site for protected species. Also, mitigation measures can contribute to the development’s sustainability, and be designed with the green infrastructure approach in mind. Incorporating well-designed natural features into developments can help contribute to the required mitigation, and provide several benefits.

Guidance note five:

Compensation will only be considered where developers/applicants have satisfactorily shown that avoidance and mitigation are impossible and compensatory measures make no net habitat loss.

For very few cases, it will be impossible either to avoid adversely affecting the site’s ecology, or to mitigate or reduce adverse effects. Compensation will then be sought. This will only be considered after all other options have been explored without finding a sufficient solution. The provision of compensation should be relevant to the loss at the development site, and should ultimately aim to provide an overall biodiversity gain.

The degree of compensatory measures needed following works on or close to roosts or bats will depend on the level of disturbance and mitigation possible. Some small effects could be balanced out with providing bat boxes on or close to the existing location. Larger effects like the complete loss of a roost will need much greater compensation such as new roost sites. That would mean a purpose built bat barn. Normally, this must be built before any demolition or alterations, and so will affect the development schedule.

Therefore it is important to fully understand the licence requirements before finalising your development programme. Whatever compensatory measures are taken, it is vital to ensure a no-loss approach and that the new measures’ functions match those of the old. An example could be where a hibernation roost has been lost due to development. Such must be replaced with an alternative site that is a suitable hibernation roost for the particular bat species which used the previous hibernation roost.

See advice on contemporary measures in Technical Advice Note (TAN) Five.

As prescribed earlier, all major and sensitive developments are expected to add to green infrastructure in some way. Further, all developments can create biodiversity enhancements through the planning process.

Larger developments will often be accompanied by a survey with recommendations for biodiversity enhancements which will often be included as conditions of the application. On this scale, we encourage developers to consider biodiversity enhancements in the design concept phase. Also we want them to challenge innovative design to not only benefit biodiversity but include multiple benefits through the Green Infrastructure Approach.

Building enhancements can help sustain the existing bat population, and where suitable roosting sites are scarce, these may improve bat numbers. Many different features can be built-in during development which can support bat populations. Fabricated bat bricks and bat boxes can be included in the construction which are unobtrusive and maintenance-free. Other bespoke features appropriate to the development like hanging tiles and timber cladding can also provide additional benefit.

The Bat Conservation Trust (BCT) shows examples of bat tiles, bricks and integrated bat boxes.

As per survey requirements, locations on the BCT trigger list which need a survey even if absent of bats will likely benefit most from enhancements. In these cases, simple biodiversity enhancements may be included as conditions of development.

Please note that the inclusion of bat box/bricks and access tiles does not replace the mitigation required as part of the licence.

Further information about bats

The (BCT) website has further information on bats and buildings. See advice on increasing biodiversity in the TAN five document.

Sometimes your development may involve an activity that imperils bats using the property as a roost. Many factors like the building’s location and condition or type, and its history of bats all influence the likelihood of bats being present. In all cases, we consider the development’s risk to bats. Occasionally whilst there is a risk of encountering bats during works because of the development’s nature, bats may not be likely to use the building. In such cases, it would not be reasonable to request submission of a bat survey.

If a bat survey is not requested

All applicants should be aware British bats, their breeding sites and resting places are protected by UK law as noted above.

Many bat species depend on buildings for roosting with each having its own preferred type of roost. Some species roost in crevices such as under ridge tiles, behind roofing felt or in cavity walls. Therefore, they are not often seen in roof space. Bat roosts are protected even when bats are temporarily absent.

Your planning application may not need a bat survey. Yet the possibility of encountering bat roosts when works start cannot be excluded without a full bat survey. The decision as to whether or not to run a bat survey lies with the applicant. However if the applicant knows of bats using the building, it is essential you commission a bat survey.

Good practice with bats

All applicants must follow good practice guidelines where their development involves any risk to bats.

Contractors should be made aware that there is a small chance of encountering bat roosts unexpectedly during the development work. In the unlikely event of bats being found onsite, work should stop immediately and advice be sought from NRW. They can be contacted at or on 0300 065 3000.

Further information on bats and buildings can be found on the BCT website.

Image credit: 'Lesser horseshoe bat (Rhinolophus hipposideros) bats roosting' by Jessicajil. Licence credit.

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