Bat Survey Season: Timings and Guidelines

When embarking on construction or development endeavours, it is essential to consider the potential effects on nearby wildlife and biodiversity. Bats, as a protected species, hold significant ecological importance and are sensitive to alterations within their habitats.

Therefore, it is vital to undertake comprehensive bat surveys as part of the planning application process. These surveys serve to evaluate the presence of bats and address their conservation requirements within the project area. If bats are found to be present, a local planning authority may delay the process until necessary mitigation measures are undertaken.

Certain bat surveys can only be undertaken at specific points in the year. Therefore, it is crucial to be aware of these time frames to ensure that your project is not affected.

When is bat survey season?

In the United Kingdom, insects serve as the main source of food for bats. Similar to other regions with temperate climates, all eighteen species of British bats enter a hibernation phase during the winter months when insect populations dwindle. This hibernation period aligns with cold weather conditions, which insects are unable to endure without extreme measures due to their lack of body fat reserves.

Therefore, bat survey season in the UK typically occurs during the warmer months, from spring through early autumn. This timeframe corresponds with the period when bats are most active and visible, making it ideal for conducting surveys to assess their populations, behaviours, and habitat preferences.

As a general range, most bat activity surveys are conducted between 01 May and 30 September, with most surveys being carried out in the summer months as this is when bat activity is at its peak. Bat activity surveys and bat emergence and re-entry surveys are all conducted during this part of the year.

Although there are certain surveys that are conducted outside of this time frame. For example, surveys for bat habitat and evidence can be carried out at any time of the year and preliminary roost assessments are undertaken prior to the bat survey season.

Therefore, it is important to consult with a professional ecologist as they can provide guidance on which time of year is best for the type of survey that is to be conducted.

Why are bat surveys important?

Bats play a vital role in ecosystems by contributing to pollination, seed dispersal, and insect control. Understanding the species of bats present in an area helps developers make informed decisions to minimise the impact on local biodiversity.

Bat surveys also provide insights into the locations of bat roosts and foraging areas. Using this information, projects can be designed to avoid critical bat habitats, preserving their roosting sites and maintaining the ecological balance.

Bats are a protected species, and the UK has regulations in place to protect them. Therefore, conducting bat surveys ensures compliance with environmental laws and permits developers to navigate potential legal challenges associated with impacting bat habitats.

Due to their ecological importance, bats are protected under national and international legislation, including the Wildlife and Countryside Act 1981 (as amended) and the Conservation of Habitats and Species Regulations 2010.

It is an offence to kill, injure, capture, or intentionally disturb bats in their natural habitats. Therefore, if it is found that bats are present on a site, developers are legally required to carry out bat mitigation and compensation measures before any development work can begin. These measures may include the creation of a bat box or roost. More information about bat mitigation measures can be found on the Bat Conservation Trust website.

What types of bats are there in the UK?

In the United Kingdom, there are various species of bats. These species vary in size, habitat preferences, and feeding behaviours. Some of the main species of bats include the common pipistrelle bat, the noctule bat, the soprano pipistrelle bat, Daubentons’ bat, the whiskered bat, Brandt’s bat, the brown long eared bat, Leisler’s bat, the Nathusius bat and many more.

It is important to note that some of these bat species are rare and have specific habitat suitability. Conservation efforts are in place to protect and preserve these fascinating creatures in the United Kingdom.

Who can carry out bat surveys?

Full bat surveys should be carried out by experienced ecologists or licensed bat surveyors who have the necessary knowledge and expertise to identify bat species, assess roosting sites, and interpret bat activity data. These professionals possess a deep understanding of bat ecology, survey methodologies, and legal requirements related to European protected species.

In the UK, bat surveys should ideally be carried out by ecologists who hold a Natural England bat survey license and a European Protected Species licence. These licenses are issued to individuals who have demonstrated sufficient skills and knowledge in conducting bat surveys and handling bats appropriately.

Additionally, some surveys may require ecologists to make multiple visits over several evenings or nights to obtain comprehensive data on the presence of bats, their behaviour, and habitat usage.

How can Collington Winter assist?

Collington Winter Environmental are a team of ecological consultants with extensive experience in undertaking bat and hibernating bat surveys on all types of development projects. Our Ecology Director, Olivia Collington, holds a Natural England Bat licence and has worked with protected species across the UK.

If it is determined that your proposed project may affect bats, our team can provide bat mitigation measures to ensure that your project meets legal requirements. We understand the importance of ecosystem services, natural resources, and natural capital, and we provide practical, realistic solutions to developers in all fields.

Please contact us ( for more information on our mitigation plans and survey work for protected species, such as bat surveys and great crested newt surveys. We also provide ecological appraisal and assessment services.

Our Director Jane Winter also provides landscape architecture services.

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