Bats are some of the UK’s most fascinating yet misunderstood mammals.
They are normally associated with spooky stories and old buildings, yet these creatures play a vital role in maintaining healthy ecosystems by controlling insect populations and supporting biodiversity.
They are also one of the UK’s most protected wildlife species, meaning it’s important to understand how they interact with our homes, buildings and development projects.
Whether you’ve discovered bats in your loft, are needing planning permission or wanting to learn more about bats, this blog covers it all. Our guide explores some of the most interesting facts about bats and answers many of the common questions homeowners and developers ask.
Why Are Bats Protected in the UK?
Did you know that bats have major environmental significance in the UK? These mammals are important indicators of how the ecosystem is doing.
Bats are crucial for pollination and insect control. They keep the population of insects down and aid in propagation of plants through seed dispersal and pollination.
As mentioned, bats can be considered as an indicator species. This means the presence or absence of these mammals can tell us the health of an ecosystem. By monitoring bat populations, we can gain valuable insights into environmental changes.
Unfortunately, bats are facing various threats. This includes habitat loss, pesticide use, climate change, and diseases like white-nose syndrome. Many of these threats have been caused by human activity and have contributed to population declines in many bat species.
How Are Bats Protected by Law?
In the UK, bats are protected by law to ensure the conservation of their populations. Here are some ways bats are safeguarded by law:
- Many bat species are listed as protected or endangered under national and international legislation. This makes it illegal to harm, harass, kill or disturb the species and its habitats without authorisation.
- The laws often include protection of bat habitats, such as caves, roosting sites, and foraging areas. Disturbance of these habitats require permits or mitigation measures to minimise impacts on bat populations.
Because bats and their roosts are protected by law, anyone planning work that could affect them has a legal responsibility to consider their presence before work begins. This is where bat surveys become important.
What is a Bat Survey?
There are several types of bat surveys. Some of the most common include Preliminary Ecological Appraisals (PEA), Preliminary Roost Assessments, Bat Emergence & Re-entry Surveys and Bat Activity Surveys.
Each survey has a different purpose, but they all help identify when they are present and how to help protect the species, their population, habitat preferences, and potential roosting sites.
During each survey, experts use specialised equipment, like bat detectors, to record echolocation calls which helps determine the types of bats present and their numbers.
Not all surveys may be needed, but it’s important to talk to expert to advise you on which you’ll need.
When Do You Need a Bat Survey?
A bat survey may be required before carrying out work where there is potential to disturb bats or their roosts.
In many cases, local planning authorities will request a survey as part of the planning process if there’s a reasonable likelihood that bats could be affected.
How Do You Know If You Need One?
If your project involves the following, you may need a bat survey:
Building Alterations or Demolitions
If you are making alterations to existing buildings, for example, conversions, renovations, or demolitions, or your project involves the construction of new buildings, then you may need to consider a bat survey.
Tree Work
Additionally, if the work includes tree felling, pruning or habitat removal, there may be a possibility of bats roosting in the trees. This may require a bat survey before approval of planning permissions.
Development in Bat Habitats
If the project is located in or near areas known to support bat populations, such as woodlands, water bodies, or urban areas with suitable roosting sites, a bat survey may be necessary.
When Should You Conduct a Bat Survey?
Usually, bat surveys are conducted during the end of spring right through to early autumn as this is when bats are most active establishing maternity roosts. The timing of your survey can affect the accuracy of the data.
What is the Lifespan of a Bat Survey?
Whilst it’s important to get the survey prior to any work being completed, one of the most common questions is how long do they last? Unfortunately, there is no simple answer as it will depend on several factors.
The location of the site and if bats are present will affect how and when you’ll need a new one. However, each survey typically involves numerous visits throughout bat activity season (May-September).
Bat surveys are valid for 2 survey seasons. For example, summer nocturnal surveys conducted in 2026, would expire on 1st May 2028 and winter hibernation surveys conducted in January/February 2027, would expire on 1st November 2028.
Initial surveys may last a few hours, while follow-up surveys and monitoring could extend over several months. The duration also depends on the recommendations outlined in the survey report and any required mitigation measures.
What is the Fine for Disturbing Bats?
In the UK, penalties can vary from fines to imprisonment as bats are a protected species. A bat survey assists in identifying potential effects on bats and assures legal compliance.
However, the surveys are more than just following requirements; they also encourage responsible environmental behaviour. It’s a method to actively contribute to the preservation of biodiversity and the delicate balance of our ecosystems.
If you’re tempted to do a bat survey on you own, it’s important to note that you’re only permitted to conduct bat surveys for the National Bat Monitoring Programme (NBMP) Roost Counts organised by the Bat Conservation Trust (BCT). You cannot conduct, lead or be part of surveys for your own planning permission as this is a conflict of interest.
Surveys for planning permission must be organised by licenced bat ecologist. To effectively estimate bat activity, experts contribute a lot of knowledge, specialised equipment, and experience. They can also make mitigation recommendations, ensuring that building or repair projects are carried out ethically and sustainably.
When Does Bat Hibernation Start?
Bats go into hibernation in winter. Hibernation is a period of deep sleep, also known as torpor, which allows animals to survive harsh cold weather. Bats enter hibernation during November and may not be fully active until the middle of May.
Where Do Bats Hibernate?
Before the winter months, bats are on the lookout for a comfy roost where they can hibernate over the winter. A roost is the place a bat lives, rests or feeds, and bats will find different roosting conditions depending on the time of year.
Many people think about bats as hanging upside down in caves, but while caves are popular with bats, bats are more likely to roost in natural features like holes in trees. As the human population increased over the centuries and natural roost sites like ancient trees became rarer, bats had to adapt to the man-made environment. This is why you may see bats in structures such as houses, barns, and even churches.
Bats are not able to bore holes or build roosts, so they make the most of whatever gaps they can find. Any location can be a roost for a bat, as long as it has a constant temperature and is free from dampness or frost. Bats will squeeze into odd positions to keep warm, which could include lying on their side or even on their head!
How Can We Help During the Bats Hibernation Period?
All UK bat numbers are decreasing. As natural habitats have been taken away by humans, bats have adapted to urban environments and can use places like our gardens as a source of food or shelter, so if you see a bat, you have a very healthy green environment. You can help bats recover by doing any of the following:
- Increase the food supply by building a pond, not using pesticides, or creating a compost heap.
- Provide shelter, for example, by placing bat boxes on tree trunks or walls of buildings in a sunny location facing the southwest and keeping old trees with splits or cracks to provide better roosting locations.
What Should We Do if We Find a Bat Roost?
You may be living with a bat roost in your attic or garden and don’t realise it, but disturbing hibernating bats is a risk to their survival. They cannot respond quickly to danger when hibernation is disturbed, and take around 30 minutes to awaken.
If you discover a roost or you don’t know how to progress, you may need a bat survey to protect the species. If any bats are found during daylight hours or on the ground, it is recommended you contact the BCT helpline.
What Do I Do If I Have Bats in My Roof?
During the warmer months, you may notice bats emerging from your rood or loft at dusk as they leave to feed. If you think bats are roosting in your property, it’s important not to disturb them and to seek professional advice before carrying out any maintenance or building work.
What To Do If You Find Bats on a Building Site
Whilst this is on a bigger scale, the same rules apply. If you encounter bats on a building site, careful planning and compliance with legal procedures is required. This is why an initial survey is both suggested and sometimes required for planning permission.
If bats are discovered during the construction process, all work must halt within the area in order to avoid any harm being done to them. It’s also important to seek further advice from professional ecologists to promptly assess the situation and advise on any mitigation measured necessary.
Bats play an important role in the UK’s ecosystem, but they’re also one of our most protected species. Whether you’re planning building work, need planning permission or have discovered bats in your roof, understanding the legal responsibilities is essential.
If you think you need a bat survey, get in touch with the Greenlight team today. We’re more than happy to help!
