How to Determine If You Need a Bat Survey (Avoid Costly Mistakes)
Understanding Planning Regulations: When Are Bat Surveys Required?
Bats are legally protected in the UK. If your development affects their habitat, you need a bat survey. No exceptions.
Planning authorities won’t give approval if there’s a risk to bats without proper assessment. The key legislation? The Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017. These laws make it an offence to disturb bats or damage their roosts—even if unoccupied.
The real challenge? Many sites could have bats, but you won’t know without a proper survey. And here’s the kicker—local planning authorities (LPAs) won’t validate your application if they suspect bats might be present and you haven’t provided evidence.
If your project involves:*
- Demolishing buildings, especially older ones with pitched roofs, loft spaces, or hanging tiles
- Converting barns, churches, or derelict farm buildings
- Removing mature trees or hedgerows
- Altering roof structures, bridges, or tunnels
- Developing near woodlands, rivers, or parkland
…then you’re in bat survey territory. Skip this step, and your planning application could be delayed indefinitely.
Key Signs That Bats May Be Present on Your Development Site
You don’t need to be an ecologist to spot potential bat activity. Look for these telltale signs before submitting your planning application:
- Bat Droppings: Small, dark, and crumbly. Often mistaken for rodent droppings but easily crushed into dust when rubbed between fingers.
- Grease Marks: Bats squeeze through tight gaps, leaving dark stains around entry points.
- Chirping Noises: High-pitched calls at dusk or dawn, particularly in loft spaces or under eaves.
- Flight Activity: Watch for bats emerging from buildings, trees, or structures at nightfall.
- Insect Presence: Bats feed on insects. A high concentration of moths, midges, or beetles around your site could indicate a food source nearby.
- Historic Records: Some sites already have known bat roosts. Check with your local records centre or planning authority.
If your site ticks any of these boxes, a bat survey is almost certainly required. Ignoring this could result in costly delays later in the planning process.
How Early Assessments Can Prevent Delays in the Planning Process
Timing is everything. Get this wrong, and your entire project could grind to a halt.
Here’s how it typically plays out:
1. You Submit Your Planning Application Without a Bat Survey
The LPA spots potential bat habitat and pauses your application. You’re now in limbo.
2. You Commission a Survey Too Late
Bat surveys are seasonal. If you miss the survey window (May to September for emergence surveys), you’ll have to wait months before ecologists can assess the site.
3. Your Survey Identifies Roosting Bats
Now you need a mitigation plan, possibly a European Protected Species (EPS) licence, and further ecological input. More time lost.
4. You Try to Rush the Process
LPAs won’t approve your application without solid ecological evidence. If you cut corners, expect rejection.
How do you avoid this mess? Simple—schedule a Preliminary Roost Assessment (PRA) as soon as you suspect bats might be present. This desk-based and on-site survey determines whether further investigation is needed. If no evidence of bats is found, you can proceed without delay.
If bats are present, you’ll need Emergence and Re-entry Surveys. These can only be carried out between May and September, so planning ahead is crucial.
The takeaway? Early assessments save you time, money, and frustration. The earlier you act, the smoother your planning application process will be.
How to Conduct a Bat Survey the Right Way (What Planners Need to Know)
The Two Essential Bat Survey Types: Preliminary Roost Assessment vs. Emergence Surveys
Not all bat surveys are the same. If you get this wrong, your planning application could hit unnecessary roadblocks. There are two primary types of bat surveys you need to know about: the Preliminary Roost Assessment (PRA) and the Bat Emergence and Re-entry Survey (BERS). Each serves a different purpose, and understanding them can save you time, money, and frustration.
A Preliminary Roost Assessment (PRA) is the first step. An ecologist inspects buildings, trees, and structures on-site to assess whether bats could be present. This is a daytime survey and involves looking for bat droppings, feeding remains, and entry points. If no evidence is found, that’s great news—you can usually move forward without further surveys.
But if potential bat roosts are identified, you’ll need a Bat Emergence and Re-entry Survey (BERS). These are carried out at dawn and dusk to monitor bat activity and confirm whether bats are using the site. You’ll need multiple survey sessions, typically between May and September, since bats are only active during warmer months.
Skipping the PRA and jumping straight to a BERS is a waste of time and money. But failing to do a BERS when required can lead to costly delays. If bats are found late in the process, you’ll have to adjust your project to accommodate them, which can mean redesigns, mitigation strategies, and even waiting until the next survey window.
Best Times of Year for Bat Surveys (And Why Timing Matters)
Timing is everything. If you miss the right survey window, your project could be delayed by months. This is where many developers and architects get caught out. The key thing to remember is that bat surveys can’t be done year-round.
A Preliminary Roost Assessment can be done at any time of year. But if a Bat Emergence and Re-entry Survey is needed, you have a limited time frame—May to September—when bats are active. Within that period, the best months are June, July, and August, when bat activity is at its peak.
Here’s why this matters: If you apply for planning permission in October and a PRA indicates that a BERS is needed, you’ll have to wait until May to carry it out. That’s seven months lost before you can even submit your application. This is a common mistake that can push back entire development timelines.
If you’re working on a tight schedule, getting a PRA done early in the year is a smart move. That way, if a BERS is needed, you can plan ahead and complete it within the same survey season. Waiting until late in the year to start the process is a gamble you don’t want to take.
How to Work with Ecologists to Ensure a Smooth Survey Process
A well-planned bat survey can make or break your project timeline. The key is working efficiently with ecologists to get the right data at the right time. Many planning delays happen because surveys are booked too late or the results aren’t properly understood.
Start by bringing in an ecologist as early as possible. If your site has older buildings, mature trees, or is near woodland, a bat survey is likely. Getting an ecologist to conduct a Preliminary Roost Assessment early means you’ll know upfront if further surveys are needed.
When booking a Bat Emergence and Re-entry Survey, make sure you understand the scheduling requirements. These surveys require multiple visits at dusk and dawn, and ecologists need time to coordinate them properly. If you leave it too late in the season, you might not get all the required visits done before bat activity declines, forcing you to wait until the following year.
Communication is critical. Ensure your ecologist provides clear reports that align with planning authority requirements. If mitigation measures are needed, these should be clearly outlined with actionable steps. An incomplete or unclear bat survey report can lead to planning application rejections, adding unnecessary delays.
If bats are found, don’t panic. There are established mitigation strategies that allow development to proceed while protecting bat populations. This could include integrated bat boxes, modified construction schedules, or habitat enhancements. The key is to have a plan in place before submitting your application.
For a deeper dive into all ecology surveys required for planning, check out Comprehensive Ecology Surveys for Planning (Expert Guidance). Proper planning upfront ensures you avoid costly mistakes and keep your project on track.
How to Use Bat Survey Results to Secure Planning Approval (Next Steps)
Understanding Bat Survey Reports: Key Findings That Impact Planning Decisions
Bat survey reports aren’t just another box to tick. They can be the difference between a smooth planning approval and months of costly delays. If bats are present on your site, planning officers will scrutinise your ecological assessment to ensure compliance with wildlife protection laws. Understanding the key findings in your report helps you stay ahead of potential obstacles.
The report will categorise bat activity into three main findings: evidence of roosting bats, potential suitability for roosting, or no evidence at all. If no bats or signs of roosting are found, you’ll likely be in the clear. However, if the site shows medium or high potential for bats, further surveys (such as emergence and re-entry surveys) will be required.
Local planning authorities (LPAs) rely on these reports to assess the ecological impact of your development. If bats are found, you’ll need to demonstrate that your project won’t harm their habitats. That’s where mitigation strategies come in.
Mitigation Strategies: What to Do If Bats Are Found on Your Site
Bats are a legally protected species in the UK, and disturbing them without proper mitigation can result in significant fines and planning refusals. If your bat survey confirms their presence, you need a clear strategy to keep your project moving forward.
Mitigation measures depend on the type of roost and the species identified. For example, if common pipistrelles are found in a roof void, simple modifications like bat boxes may be enough. However, if rare species or maternity roosts are present, you might need to provide alternative roosting sites, adjust construction schedules, or even secure a bat mitigation licence from Natural England.
Timing is crucial. You may need to schedule works outside of breeding or hibernation seasons to minimise disturbance. This can mean waiting months if your planning isn’t aligned with ecological constraints. However, proactive adjustments, such as phased construction or temporary roosting provisions, can help mitigate delays.
The best approach? Engage with an experienced ecologist early. They can help design a mitigation plan that satisfies planning authorities while keeping your project on schedule.
How to Submit Bat Survey Evidence to Meet Planning Requirements and Avoid Rejections
Once you have your bat survey and mitigation strategy in place, the final step is submitting your evidence correctly. Planning officers require clear, well-documented reports that demonstrate compliance with wildlife regulations. A poorly presented or incomplete submission can trigger requests for further information, delaying your approval.
Your bat survey report should include:
- A detailed site assessment, including survey dates and methodologies.
- Clear findings specifying bat species, numbers, and roost locations.
- Impact assessments showing how the development may affect bats.
- Proposed mitigation strategies, including alternative roosting provisions.
- Evidence of consultation with ecological experts and, where necessary, Natural England.
If a bat licence is required, plan for additional processing time. Natural England can take several weeks to approve applications, and work cannot proceed until a licence is granted.
Submitting complete, well-structured reports that align with planning policies increases your chances of fast approval. Engage with a professional ecological consultancy to ensure your documentation meets all requirements.
Need expert guidance on bat surveys and planning approvals? Get in touch with our ecological consultancy here to ensure your project stays on track.