Bat Survey
Bat surveys are among the most common ecological requirements for planning applications in the UK. All 18 species of bat found in Britain are protected under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017, making it a criminal offence to disturb or harm bats or their roosts without a licence.
Typical Cost
£300 – £5,000+
Turnaround
1 – 6 weeks
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What is a Bat Survey?
A bat survey is a specialist ecological assessment that determines whether bats are using a building or site for roosting, foraging, or commuting. The survey typically involves two stages: a Preliminary Roost Assessment (PRA) where an ecologist inspects the building or trees for signs of bat use, followed by emergence and re-entry surveys where ecologists watch the building at dusk and dawn to observe bats leaving or returning to roosts.
When is a Bat Survey required?
A bat survey is usually required when your proposed development involves demolition, conversion, or significant alteration of buildings — particularly older structures with features like hanging tiles, timber cladding, gaps under ridge tiles, or access to roof voids. Work affecting mature trees with holes, cracks, or loose bark may also trigger a survey requirement. Your local planning authority's ecologist will flag the need for a bat survey if they consider there is reasonable likelihood of bats being present.
What does a Bat Survey include?
A full bat survey report includes a description of the site and surrounding habitat, findings from the preliminary roost assessment including any physical evidence of bats such as droppings or staining, results of dusk emergence and dawn re-entry surveys, identification of bat species present, assessment of roost type and significance, an evaluation of the potential impact of the proposed development, and recommended mitigation or compensation measures where needed.
How much does a Bat Survey cost?
A Preliminary Roost Assessment typically costs between £250 and £450. If the PRA identifies potential for bat use, follow-up emergence surveys are needed, with each survey visit costing £400 to £700. A standard residential project requiring a PRA plus two or three emergence surveys usually comes in between £900 and £1,800 in total. Larger or more complex sites with multiple buildings or significant bat populations can cost considerably more.
Who can prepare a Bat Survey?
Bat surveys must be carried out by a licensed ecologist who holds a Natural England bat survey licence (or equivalent for Wales and Scotland). This licence confirms the ecologist has the training and experience to handle and disturb bats legally. Many ecology consultancies employ licensed bat surveyors, and you should always verify that your chosen consultant holds a current licence before commissioning work.
How long does a Bat Survey take?
The timing of bat surveys is strictly governed by the bat activity season, which runs from May to September, with the optimal survey period being May to August. A Preliminary Roost Assessment can be carried out at any time of year and takes a few hours on site. Emergence surveys must be conducted during the active season, with a minimum of two visits spaced at least two weeks apart. From start to finish, completing a full bat survey typically takes 4 to 8 weeks during the survey season.
Frequently Asked Questions
What time of year can bat surveys be carried out?
Preliminary Roost Assessments can be done at any time of year. However, the emergence and re-entry surveys that follow must be conducted between May and September, when bats are active. The optimal period is May to August. Surveys outside this window are not considered valid by planning authorities, which is why early planning is essential to avoid delays.
What happens if bats are found during the survey?
Finding bats does not automatically prevent development. If bats or their roosts are confirmed, your ecologist will design a mitigation strategy that might include timing works to avoid sensitive periods, installing bat boxes as alternative roosts, incorporating bat-friendly features into the new building design, or applying for a European Protected Species licence from Natural England.
Can I do a bat survey myself?
No. It is a criminal offence to disturb bats without a licence. Only ecologists holding a valid bat survey licence from Natural England, Natural Resources Wales, or NatureScot are legally permitted to carry out surveys that may involve disturbance to bats. Attempting a survey without a licence could result in prosecution and fines of up to £5,000 per offence.
How many bat survey visits are needed?
The number of survey visits depends on the building's potential to support bats, as assessed during the Preliminary Roost Assessment. Buildings with low potential typically require one dusk emergence survey. Moderate potential buildings need two surveys — one dusk and one dawn. High potential buildings require three surveys, with at least one dusk and one dawn visit. Surveys must be separated by at least two weeks.
Do I need a bat survey for a loft conversion?
Possibly. If your loft conversion involves changes to the roof structure, replacement of tiles, or alteration of the roof void, your planning authority may require a Preliminary Roost Assessment before granting permission. Older houses, rural properties, and buildings near woodland or water are more likely to support bat roosts.
What does a bat survey cost for a single house?
For a standard residential property, expect to pay around £250 to £450 for the initial Preliminary Roost Assessment. If emergence surveys are required, the total cost typically ranges from £900 to £1,500 including the PRA and two to three evening survey visits. Costs vary by region and the complexity of the building.
Will a bat survey delay my planning application?
It can, particularly if you miss the survey season. If your Preliminary Roost Assessment is done outside the active season and identifies bat potential, you will have to wait until May to begin emergence surveys. This is why ecologists recommend commissioning a PRA as early as possible, ideally before submitting your planning application, so that any follow-up work can be scheduled promptly.
Are bat droppings a definite sign of a roost?
Bat droppings are strong evidence that bats are using a building, but they can persist for many years after bats have left. A single dropping does not necessarily confirm an active roost. Your ecologist will consider droppings alongside other evidence such as urine staining, scratch marks, feeding remains, and the condition and location of the droppings to determine whether a roost is currently active.
Can I get a bat survey done in winter?
You can get a Preliminary Roost Assessment done in winter, which involves inspecting the building for signs of bat use. However, emergence and re-entry surveys cannot be carried out between October and April because bats are hibernating and not active. If your PRA identifies bat potential during winter, you will need to wait until May to complete the full survey.
What is a European Protected Species licence?
A European Protected Species (EPS) licence, sometimes called a bat mitigation licence, is issued by Natural England and allows you to carry out work that would otherwise be illegal because it affects a bat roost. You need this licence if your development will destroy, damage, or obstruct access to a confirmed bat roost. The application process typically takes 30 working days and requires a detailed method statement prepared by your licensed ecologist.