Bat Emergence Survey (BERS)
A bat emergence survey (BERS) is a key stage in the ecological assessment process where there is potential for bats to be present. It is typically required following a preliminary roost assessment and provides robust evidence to support planning applications.
Across England, bats are legally protected species and their roosts are protected whether bats are present or not. Development proposals must therefore consider potential impacts, and planning authorities often require bat activity survey data before determining applications.
A bat emergence and re-entry survey helps establish presence, activity levels, roost usage and interaction with the surrounding landscape, supporting planning decisions and wildlife conservation strategies.
ACP Consultants Ltd provides bat emergence surveys across England, working with homeowners, architects and developers to deliver clear, planning-ready ecological reports aligned with national guidance.
We follow a simple, transparent process to ensure your project runs smoothly from the very first contact to the final report. Our approach is designed to provide you with clarity at every step, so you’re fully informed and confident in moving forward.
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Step 1: Request a Quote
Fill out our quick quote form or call us, and our team will provide a free, no-obligation quote, outlining the services tailored to your needs.
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Step 2: Confirm Your Booking
Once you approve the quote, simply return the booking form. We’ll schedule your survey and ensure all the details are taken care of.
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Step 3: Receive Your Report
After your survey is completed and payment is received, we’ll promptly issue your survey report, ensuring you get the results as quickly as possible.
In the past year, we’ve delivered over 750+ audit-ready reports supporting 400+ projects for developers, planners, and architects nationwide. We put quality over quantity and build lasting relationships based on trust, ensuring your planning applications are backed by robust evidence and delivered on time.
What is a Bat Emergence Survey (BERS)?
A bat emergence survey is a detailed ecological survey undertaken at dusk or dawn to observe bats leaving or returning to roosts. It is one of the most reliable ways to confirm the presence of bats and understand their behaviour.
Often referred to as a bat re-entry survey, dusk bat survey or dawn bat survey, this form of bat activity survey builds on earlier assessments by providing direct observational evidence.
During the survey, ecologists monitor buildings or trees with potential roost features and record bat activity using visual observation and acoustic bat monitoring equipment. This allows identification of echolocation in bats, enabling species-level analysis where possible.
Bat emergence surveys help determine:
- Whether bats are present
- The number of bats using a roost
- Roost access points and behaviour
- Commuting routes and surrounding habitat use
- Bat species identification
These surveys form part of a wider suite of biodiversity surveys and may contribute to environmental impact assessments where developments are larger or more complex.
Do I Need a Bat Survey for Planning Permission?
Planning authorities across England may request a bat survey where there is a reasonable likelihood that bats could be affected by development.
You may need a bat emergence survey if your project includes:
- Roof works, including repairs, replacements or loft conversions
- Demolition or alteration of buildings
- Barn conversions or redevelopment of agricultural structures
- Removal or pruning of mature trees
- Installation of external lighting
- Development near rivers, woodland edges or hedgerows
In many cases, these features are associated with habitats commonly used by bats for roosting, commuting or feeding.
Where a site includes such features, a preliminary roost assessment is typically required first. If this identifies potential bat roost features, bat emergence surveys may be recommended to provide further evidence.
This staged approach ensures that planning decisions are informed by appropriate ecological information without unnecessary survey work.
Survey Pathway
Bat surveys for planning follow a structured and proportionate pathway. This approach provides sufficient ecological information while avoiding unnecessary survey work. It aligns with recognised bat survey guidelines and supports planning decisions across England. It also ensures the right level of evidence is provided at the right stage.
A preliminary roost assessment (PRA) is the first step. This involves a daytime inspection of buildings or trees. The survey identifies potential bat roost features and assesses habitat suitability. The ecologist considers roof spaces, gaps, crevices, loft voids and mature trees. They also assess surrounding habitat links. These may include hedgerows, rivers, gardens, canals and woodland edges.
If bat roost potential is identified, bat emergence and re-entry surveys (BERS) are undertaken. These surveys confirm presence, activity levels and roost usage. They usually involve a dusk bat survey, dawn bat survey or both. Acoustic bat monitoring supports the survey findings. Bat species identification is completed where possible.
Where bats are confirmed, mitigation measures and licensing support may be required. This may include timing works to avoid disturbance. It may also include retaining roost features, sensitive lighting design or alternative roosting provision. A protected species licence may be needed if roosts could be affected.
This pathway helps homeowners, architects, planning consultants and developers understand ecological constraints early. It also helps reduce planning risk and prepare planning-ready information for local authority review.
Preliminary Roost Assessment (PRA)
A preliminary roost assessment (PRA) is the first stage in the bat survey pathway. It involves a daytime inspection of buildings or trees. The ecologist assesses whether features are present that could support bats. They also evaluate the surrounding habitat. This helps determine the site’s overall bat roost potential.
For buildings, this may include checking roof voids, loft spaces, soffits and fascias. It may also include roof tiles, brickwork gaps, timber beams and wall cavities. Other access points are also reviewed. These features could be used by roosting bats.
For trees, the assessment may consider cavities, splits and lifted bark. It may also include woodpecker holes, dense ivy or other features suitable for bats.
The PRA also reviews the wider landscape context. This includes nearby woodland edges, hedgerows, rivers, canals, gardens, mature trees and green corridors. These features may support bat commuting or foraging activity.
If the preliminary roost assessment identifies suitable features or habitat links, bat emergence and re-entry surveys (BERS) may be recommended. These surveys confirm whether bats are present. They also show how bats use the site.
This staged approach keeps survey work proportionate, planning-led and aligned with recognised bat survey guidelines.
Bat Emergence & Re-entry Surveys (BERS)
Where potential is identified, bat emergence surveys are undertaken to provide direct evidence of bat presence. They also record activity levels and roost usage. These surveys help confirm whether bats are using a building or tree. They also show where bats are entering or leaving. This helps explain how bats interact with the surrounding habitat.
Bat emergence and re-entry surveys (BERS) typically include a dusk bat survey, a dawn bat survey, or both. The approach depends on the level of bat roost potential. It also follows recognised bat emergence survey guidelines. During each visit, ecologists position themselves around the structure or tree. They observe flight behaviour, roost access points, commuting routes and feeding activity.
Surveys are supported by acoustic bat monitoring equipment. This records echolocation in bats and assists with bat species identification where possible. It helps establish whether pipistrelle bats, brown long-eared bats or other UK bat species are present.
The results assess how the proposed development could affect bats. They also identify whether mitigation, further survey work or licensing support may be required. This ensures the BERS stage provides clear, planning-ready evidence for architects, developers, planning consultants and local authorities.
How Bat Emergence and Re-entry Surveys Work
Bat emergence surveys are carefully planned and carried out by qualified ecologists using recognised methodologies.
Dusk Bat Survey
Dusk surveys begin before sunset and continue into darkness. Ecologists observe bats emerging from roosts and record flight behaviour.
Dawn Bat Survey
Dawn surveys take place before sunrise and focus on bats returning to roosts. These surveys can help confirm roost locations and activity patterns.
Acoustic Bat Monitoring and Species Identification
Specialist detectors record echolocation calls, which are analysed to support bat species identification. This is an essential component of bat activity surveys and helps determine the ecological importance of a site. Survey techniques may include: 1. Visual observation 2. Acoustic bat monitoring 3. Mapping of commuting routes 4. Recording environmental conditions Bat migration patterns and seasonal activity levels are also considered when interpreting results.
Mitigation & Licensing Support
Where bats are confirmed during survey work, ecologists may recommend mitigation measures to ensure development does not negatively affect protected species and complies with relevant legislation. Mitigation strategies are designed around the survey findings, the type of development proposed and the importance of the roost or habitat affected.
Mitigation measures can include:
- Timing of works to avoid disturbance
- Retention of roost features where possible
- Installation of bat boxes or alternative roosting habitat
Additional measures may involve sensitive lighting design, protection of commuting routes, habitat enhancement or the creation of alternative roosting opportunities where appropriate. The objective is to avoid or reduce impacts on bats while allowing development to proceed in a responsible and planning-compliant manner.
In some cases, a protected species licence may be required before works proceed, particularly where roosts could be affected by demolition, roof alterations, barn conversions, tree works or redevelopment projects. Ecologists can provide guidance throughout the licensing process, including the preparation of supporting documentation, mitigation plans and ecological method statements where required.
These measures help support habitat preservation, maintain bat populations and ensure development proposals align with planning expectations, recognised ecological guidance and wildlife conservation objectives. By addressing ecological requirements early, project teams can better manage planning risks and reduce the likelihood of delays later in the development process.
Bat Survey Season & Timelines
Bat emergence survey season typically runs from May to September. This reflects the period when bats are most active and conditions are suitable for survey work. During this season, bats are more likely to emerge from roosts, commute through the landscape and forage along hedgerows, rivers, woodland edges, gardens and green corridors.
Bat emergence survey timings depend on several factors, including:
- Weather conditions
- Temperature thresholds
- Time of sunset and sunrise
- Bat activity levels
Dusk bat survey visits are usually planned around sunset, while dawn bat survey visits are timed before sunrise to record bats returning to roosts. Suitable weather is important because cold, wet or windy conditions can reduce bat activity and affect survey reliability.
Because surveys are seasonal, early planning is essential. Delays in booking surveys can impact project timelines, particularly where multiple survey visits are required to meet bat emergence survey guidelines. This is especially important for roof works, demolition, barn conversions, tree works and planning applications with fixed submission dates.
A bat emergence survey calendar is often used to plan survey windows, coordinate surveyor availability and ensure surveys are completed within the correct seasonal period. Early engagement with an ecologist helps reduce the risk of missed survey windows, planning delays and avoidable programme disruption.
Check If You Need a Bat Survey for Planning
Bat survey requirements can vary depending on your property, location and development type. Our experienced ecologists can review your proposal, assess bat roost potential, and confirm whether a preliminary roost assessment or further surveys are required before you submit your planning application.
What You Receive from a Bat Emergence Survey Report
Your bat emergence survey report includes a professional, planning-ready ecological report suitable for planning submission and to support planning applications or discharge of planning conditions where required. The report is structured clearly so it can be reviewed efficiently by planning officers, ecological consultees, architects and project teams working across England. This ensures ecological information is presented in a format that aligns with local authority and national planning expectations.
Typical contents include:
- Site description and building assessment – outlining the property, building type and surrounding habitat context. This may include nearby features such as rivers, woodland edges, hedgerows or urban green corridors, and how these influence bat roost potential and bat activity.
- Survey methods used – explaining how the bat emergence survey was completed, including dusk bat survey and dawn bat survey techniques, acoustic bat monitoring and recognised bat emergence survey guidelines.
- Bat activity survey results – presenting observations from bat emergence and re-entry surveys, including bat species identification where possible.
- Assessment of ecological impact – explaining how bats and their habitats may be affected by development in a planning context.
- Recommendations and next steps – providing clear guidance on further surveys, mitigation or licensing requirements where necessary.
Costs and Timescales
Bat emergence survey cost varies depending on the specific requirements of each site, including the scale of the project, level of ecological risk and survey effort needed to meet recognised guidance standards. A simple residential roof alteration may require fewer surveyor positions than a larger demolition, barn conversion or redevelopment scheme with multiple buildings, trees or habitat features.
Key factors influencing cost include:
- Site size and complexity
- Number of survey visits required
- Accessibility of structures or trees
- Level of bat activity observed
The cost of bat emergence surveys may increase where multiple visits are required, where several surveyors are needed to cover all elevations, or where dusk bat survey and dawn bat survey visits are recommended. Acoustic bat monitoring, data review and preparation of the bat emergence survey report are also reflected in the overall fee.
Timescales are influenced by bat emergence survey season, suitable weather conditions, surveyor availability and the required survey windows. Because surveys are generally undertaken between May and September, early engagement with an ecologist can help manage programme risks, avoid missed seasonal windows and reduce the likelihood of planning delays. ACP Consultants Ltd can provide a tailored quote based on your site, planning requirements and development timetable.
Local Policy & Planning Considerations
Planning authorities across England follow national policy and guidance when assessing ecological impacts, including those relating to bats. Because bats and their roosts are legally protected, planning applications must provide enough ecological information for councils to understand potential impacts before decisions are made.
Key considerations include:
- The requirement for sufficient ecological information to support planning decisions
- The protection of species under wildlife legislation
- The need to avoid harm to bat roosts and habitats
- Integration of biodiversity surveys into planning applications
Local planning authorities may reference ecological survey requirements within validation checklists, local plans or supplementary planning documents. While policies vary between councils, the underlying approach is consistent: development proposals should demonstrate that protected species have been adequately considered.
For projects involving roof works, demolition, barn conversions, tree removal, lighting or redevelopment near rivers, woodland edges, hedgerows or green corridors, councils may request a preliminary roost assessment or bat emergence surveys. This helps confirm whether bats are present and whether mitigation, timing controls or licensing support may be required.
Providing clear bat survey evidence early can support smoother validation, reduce avoidable delays and help planning officers, ecological consultees, architects and developers understand the next steps in the planning process.
Local Context Across England
Across England, the need for bat emergence surveys reflects the diversity of building types, landscapes and habitats found in both urban and rural areas. Many towns and cities include older housing stock with tiled roofs, loft voids, soffits, timber features and brickwork crevices that can provide suitable roosting opportunities for bats, particularly where buildings are close to gardens, parks or mature trees.
In rural areas, agricultural buildings, barns and farmhouses are particularly associated with bat roosts. These structures often provide sheltered, undisturbed spaces and are frequently located close to hedgerows, woodland edges, rivers, canals, ponds and open foraging habitat. This makes them common triggers for bat activity surveys during barn conversions, demolition or redevelopment.
The wider landscape also plays an important role. Rivers, canals, woodland edges and hedgerows can act as commuting routes, allowing bats to move between roosting and feeding areas. Development proposals near these features may increase the likelihood of requiring bat emergence surveys, especially where lighting, roof works or tree removal could affect bat behaviour.
Urban areas also present important habitats. Parks, gardens, churchyards, green corridors, railway edges and waterside routes provide feeding opportunities, while buildings can offer roosting sites. By assessing both structures and surrounding habitat, ecologists can understand how bats may use the site and provide planning-ready recommendations.
Local Coverage (England-Wide)
ACP Consultants Ltd provides bat emergence surveys across England, supporting projects in major cities, regional centres and surrounding rural areas. Our national coverage includes locations such as London, Birmingham, Manchester, Leeds, Bristol, Cambridge, Oxford, Newcastle, Nottingham and Southampton, where bat survey requirements often arise during planning applications, roof works, redevelopment and site clearance.
In larger urban areas such as London, Birmingham, Manchester and Leeds, bat emergence surveys are commonly needed for older buildings, loft conversions, demolition, extensions and regeneration schemes. These locations often include roof voids, brickwork gaps, mature gardens, parks, canals and green corridors that can support bat activity.
In places such as Bristol, Cambridge, Oxford, Newcastle, Nottingham and Southampton, survey requirements may also relate to historic buildings, riverside development, university estates, suburban housing, mature trees and development near woodland edges or waterways. These features can provide suitable roosting, commuting and foraging habitat for bats.
Whether the project is in a city centre, suburb, village or rural edge location, ACP Consultants Ltd can provide planning-ready bat emergence survey reports to support local authority validation, ecological review and the next steps in the planning process.
Common Project Types in This Area
Bat emergence surveys are commonly required for a wide range of development projects across England, particularly where works could affect buildings, trees or habitats with bat roost potential. These surveys help provide planning authorities with clear ecological evidence before applications are determined.
For residential extensions and roof alterations, a bat survey may be needed where works involve roof voids, tiles, soffits, fascias, chimneys or older building materials that could support roosting bats. This is especially relevant for loft conversions, roof replacements and extensions to mature properties.
Barn conversions and agricultural redevelopment can also trigger survey requirements, as barns, stables and farm buildings often contain open roof spaces, timber beams, gaps in masonry and surrounding foraging habitat.
Where demolition of existing structures is proposed, bat emergence surveys may be required to confirm whether bats are present before works begin. This supports planning compliance and helps avoid disturbance to protected species.
Projects involving infrastructure and lighting schemes may need assessment because artificial lighting can affect bat commuting routes, feeding areas and roost access points.
Tree removal for development may also require survey input where mature trees contain cavities, loose bark, splits or other potential roost features.
For large-scale development requiring environmental impact assessments, bat activity survey data can help inform ecological impact assessment, mitigation design and wider biodiversity considerations.
Why Choose ACP Consultants Ltd
ACP Consultants Ltd provides bat surveys in England with a strong focus on planning support and ecological best practice. Our team includes experienced ecologists working to recognised standards, including guidance from Natural England, the Bat Conservation Trust and CIEEM, ensuring survey work aligns with current bat survey guidelines and planning expectations.
We support homeowners, architects, planning consultants and developers through the full survey pathway, from preliminary roost assessment to bat emergence surveys, mitigation advice and licensing support where required. This helps project teams understand ecological constraints early and prepare suitable information for planning submission.
We provide:
- Nationwide coverage
- Clear, planning-ready reports
- Support across the full survey pathway
- Experience working with a wide range of development types
With experience across residential extensions, roof alterations, barn conversions, demolition, tree works, lighting schemes and larger developments, ACP Consultants Ltd provides proportionate advice tailored to each site. Our approach is designed to support efficient planning progression, with clear communication, practical recommendations and reports structured for planning officers and ecological consultees.
By combining national coverage with planning-led ecological expertise, we help clients manage survey timing, understand requirements and progress projects responsibly while maintaining appropriate safeguards for bats and their habitats.
References and Useful Resources
- Chartered Institute of Ecology and Environmental Management (CIEEM) – Bat Survey Guidelines for UK Homeowners
- CIEEM – What to Expect from a Bat Survey: Homeowner guide to survey stages, reporting and outcomes
- CIEEM – Bat Mitigation Guidelines (2025): Best practice guidance for mitigation design and implementation
- GOV.UK – Bats: Advice for Making Planning Decisions
- GOV.UK – Bats: Protection, Surveys and Licences
- GOV.UK – Protected Species: How to Review Planning Applications: Guidance for assessing ecological impacts within planning decisions
- Natural England – Bat Advice Service (BAS) Updates and Guidance
- Bat Conservation Trust – British Bat Survey (Passive Acoustic Surveys)
- Bat Conservation Trust – Contacting an Ecological Consultant: Advice on engaging a qualified bat ecologist for surveys and planning
- Bat Conservation Trust – Planning and the Law: Overview of legal protections and planning considerations for bats
- Bat Conservation Trust – Building or Development Works: Guidance on managing bats during construction and development
- Bat Conservation Trust – Planning and Infrastructure Act: Policy context affecting biodiversity and development
- Bat Conservation Trust – Planning and Infrastructure Policy Update (2026): Latest developments in planning and biodiversity policy
- Bat Conservation Trust – National Bat Monitoring Programme Surveys
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Frequently Asked Questions
A bat emergence survey (BERS) is a key stage in the planning process where there is potential for bats to be present. Typically carried out at dusk or dawn, it provides robust evidence on bat activity, roost locations and behaviour. As bats and their roosts are legally protected in England, planning authorities often require this survey to assess potential impacts before granting permission. The findings support planning decisions, inform mitigation where necessary, and ensure development proposals are backed by clear, compliant ecological information.
What is a bat emergence survey?
A bat emergence survey is a dusk or dawn survey used to observe bats leaving or returning to roosts, confirm their presence and support planning applications.
Do I need a bat survey for planning permission?
Planning authorities may require bat surveys where development could affect bat habitats or roosts, ensuring sufficient ecological information is provided.
Do I need a bat survey to replace my roof?
Roof works may require a bat survey if the building has features suitable for bats, particularly in older properties or those near suitable habitat.
When is bat emergence survey season and how does the survey calendar work?
Bat emergence survey season typically runs from May to September. A bat emergence survey calendar helps plan surveys within this seasonal window when bats are active.
What are bat emergence survey timings?
Bat emergence survey timings relate to surveys being undertaken at dusk or dawn, depending on whether bats are emerging or returning to roosts.
How many bat surveys are required?
The number of bat emergence surveys required depends on site potential and bat emergence survey guidelines, which set out survey effort and visit numbers.
What are bat emergence survey guidelines?
Bat emergence survey guidelines define how surveys should be undertaken, including timing, weather conditions, survey methods and reporting standards.
What is the difference between a bat emergence and re entry survey?
A bat emergence and re entry survey includes both dusk bat survey and dawn bat survey visits to fully assess bat activity, roost usage and behaviour.
What is included in a bat emergence survey report?
A bat emergence survey report includes site details, survey methods, bat activity survey results, bat species identification, impact assessment and recommendations.
How much does a bat emergence survey cost?
Bat emergence survey cost varies depending on site complexity, number of visits and survey requirements. The cost of bat emergence surveys is influenced by guidance standards.
Do bat surveys contribute to biodiversity surveys and environmental impact assessments?
Yes, bat surveys form part of biodiversity surveys and may contribute to environmental impact assessments where development could affect protected species.
Why are bat surveys important for wildlife conservation strategies and what happens if bats are found?
Bat surveys support wildlife conservation strategies by identifying roosts and protecting habitats. If bats are found, mitigation or licensing may be required before works proceed.
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- Last Updated:
- October 2026
Disclaimer: Our content is prepared by ACP Consultants’ in-house specialists and is based on current guidance, standards, and best practice in environmental consultancy. While we make every effort to keep information accurate and up to date, it is provided for general guidance only and should not be relied upon as a substitute for professional advice on specific projects. Planning authorities retain final decision-making powers, and requirements may vary between local authorities and over time. ACP Consultants accepts no liability for any loss arising from reliance on this content without obtaining tailored advice for your project.