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Bat survey

Bat Surveys

Bat survey

All UK bat species and their roosts are protected by law; it is illegal to disturb, injure or kill a bat, or to obstruct, damage or destroy a bat roost. A bat survey should be undertaken where there is a possibility that bats or their roosts may be affected by proposed works.

Although some bats roost in old buildings and churches, many prefer centrally heated modern houses. The nearby proximity of woodland, rivers and ponds may also increase the chances of bats being present.


Where a project requires planning consent, the local planning authority has a duty to consider bats when exercising their functions. Bats are a ‘European Protected Species’ and, as such, are a material consideration in the planning process. This means information regarding their presence or absence must be provided prior to any consent being granted, and bat surveys cannot be conditioned within planning approval. Bat surveys must be carried out at the correct time of year, when bats are active (bats hibernate over the winter months), and good planning is key.

Bat surveys are carried out in two parts:

January - December

Risk Assessment

January - December

This is a preliminary daytime inspection to determine the likelihood of bats being present within a structure. 

The risk assessment consists of a desk based study, including a background data search of known roosts in the area.

A licensed ecologist will visit the property to carry out an internal (where appropriate) and external inspection of the structure.

Activity Surveys

May - August

Where the preliminary inspection identifies a risk of bats being present, nocturnal activity surveys are undertaken to determine the presence or absence of roosting bats.

These surveys involve up to three visits to the exterior of the property or structure at dusk. to monitor bat activity.

We use Night Vision Aids (NVAs) such as infra-red technology to enhance our bat activity surveys

(click here to view footage).

Earned Recognition

Protected Species Licensing

Where bats are found to be roosting in a structure, and will be affected by the proposals, it is likely the project can still go ahead. Timing and methods of working may need to be adapted, and a licence may need to be obtained from Natural England to permit activities that would otherwise be illegal.

As part of the licensing process, new roosting provisions for bats are designed into the new development, which replicate those conditions provided by the old structure. Durham Dales Ecology has years of experience of designing mitigation strategies for bats, which culminate in successful planning approval and Natural England licences. 

Earned Recognition Accreditation

The Bat Earned Recognition Project is a professional accreditation scheme, launched in 2022 through a partnership between Natural England, the Bat Conservation Trust and the Chartered Institute of Ecology and Environmental Management. The scheme is designed to streamline bat mitigation licensing, whilst also raising and maintaining professional standards in bat mitigation work and improving outcomes for bats. Earned Recognition works on the basis of assessing a consultant's competence in undertaking bat survey work and designing effective mitigation so that, by using an accredited consultant, developers can experience a more streamlined and efficient licensing process for their scheme or project.


Fran Mudd of Durham Dales Ecology has successfully completed the rigorous assessment process required of participants in this scheme, and is pleased to be part of the first cohort (of around 60 individuals across the country) of Earned Recognition accredited consultants.

Bat survey
Bat mitigation licence
  • I have never seen a bat near my property. Why do I need a bat survey?
    Bats are very unobtrusive creatures. They do not build nests, chew or gnaw - they will only make use of existing cracks and crevices to access buildings. Bats can squeeze deep into small gaps of only 10mm and may leave no visible evidence of their presence. Bats often roost in houses, both new and old. Quite often, applicants are surprised to find out they have bats.
  • If no live bats are seen during the risk assessment, do I still need further survey work?
    Bats are known to use several different roosts throughout the year, and may not be in residence at the time of the survey. Bats are very faithful to these roosts and will return year after year. For this reason, bat roosts are protected by law even when the bats are not present. Also, bats can roost deep inside buildings, such as in cavity walls and between roofing slates and the membrane beneath, making roosts difficult to identify during a visual assessment. In cases where there are features suitable for roosting bats and it is not possible to conclusively rule out a bat roost, nocturnal surveys may still be required.
  • If my property is risk assessed as having no potential for bats, do I need to carry out further survey work?
    No - If the initial risk assessment reveals there are no gaps within the structure which are suitable for roosting bats then no nocturnal survey work with respect to bats will be recommended.
  • If nocturnal surveys are required, how many will I need?
    This will depend on the level of risk presented by the structure. Structures with very few gaps suitable for bats may require only one nocturnal survey, whilst buildings with a high risk of containing bats may require at least three nocturnal surveys. If a roost is discovered during one of the nocturnal surveys, the number of surveys may increase.
  • If nocturnal surveys are required, how quickly can they be carried out?
    Bats hibernate during the winter months and therefore nocturnal surveys can only be carried out between May and August. Surveys should be spaced out throughout this period where possible, but always with a minimum of three weeks between surveys.
  • Can nocturnal surveys be conditioned and undertaken after planning consent has been granted?
    No - Planning authorities must make sure they have all information relating to the presence or likely absence of protected species, including bats, before they decide whether or not to grant planning consent. It is the applicant's responsibility to provide all relevant supporting information to the local planning authority to enable them to make a decision.
  • If I have bats, will I be able to continue with my project?
    Except in very rare circumstances, the presence of bats is unlikely to prevent development. If bats already exist on site, the effects of development may be mitigated by designing and incorporating roosting and feeding opportunities into the proposed site. This ‘mitigation strategy’ will be developed with the best interests of both the bats and the applicant in mind, and will be tailored to suit each individual project.
  • Can I incorporate a bat box into my proposed designs to avoid carrying out nocturnal surveys?
    No - As a mitigation strategy (see above) is specific to each species of bat and type of bat roost, information must first be gathered to inform the type of bat roosting feature to be incorporated into the designs. This will ensure the requirements of the bats are met so they are able to continue to use the structure. This information is collected during nocturnal surveys.
  • Can I apply for a Protected Species Licence while I wait for my planning permission to be granted?
    No - A European Protected Species Mitigation Licence for a development can only be applied for after planning permission has been granted.

Get In Touch

We'd love to hear about your project. To arrange a bat survey, or for an informal, no obligation chat, contact us at, call us on 07525128586, or complete the contact form below and we'll get back to you as soon as possible.

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