Bats play a key environmental role in the control of pests such as mosquitoes and midges, as well as pollinating flowers and helping to spread their seeds. The UK is home to eighteen species of bat (seventeen breeding), but sadly their numbers have declined considerably, and all UK bat species and their resting places (known as roosts) are now protected by law.

Why do I need a bat survey?

You may have been asked for a bat survey by your Local Planning Authority if your development involves roof works, demolition, conversion or alteration of a building, which has the potential to impact roosting bats. If you have any trees on your site, or potential bat foraging or commuting routes on larger sites that could be impacted, these may also require further investigation.

All UK bat species are strictly protected by law, making it a criminal offence to kill, injure or disturb a bat, or damage or destroy a bat roost without a licence, even if no bats are present at the time.

Qualified and experienced ecologists carry out surveys to establish the presence or likely absence of bats and whether they will be affected by your proposals. Bats can roost in the tiniest of spaces, such as between rafters in the roof void, between the roof lining and tiles, and in gaps between walls and fascia boards. If you don’t know what you’re looking for you probably wouldn’t even know they are there.

What is the process of conducting bat surveys?

Preliminary Roost Appraisal (PRA)

The first stage of bat surveys is a Preliminary Roost Appraisal (sometimes called a daytime bat assessment). This survey can be carried out all year round, without any seasonal restrictions.

The building or structure will be inspected externally and internally, including lofts and cellars, by a qualified and licensed ecologist, who will search for any signs of bats (such as droppings), and for any small gaps that could potentially be used by bats; these are called Potential Roost Features (PRFs). Trees will be inspected for PRFs such as rot holes and flaking bark.

A report will then be provided, outlining our findings and assigning a level of potential for the building, which will then determine whether any further (Phase 2) surveys are required. The level of potential (negligible, low, moderate or high) is determined by factors including evidence of the presence of bats, how many PRFs are present, the type and age of the building and its location and surrounding habitat.

If your building(s) has negligible potential at this point, no further surveys are required, and the report can be submitted as part of your planning application.

Phase 2 Presence/Absence and Roost Characterisation Surveys

If the PRA cannot rule out the presence of bats, Phase 2 surveys are likely to be required, with the number of further surveys needed ranging from one survey (low potential) to three surveys (high potential, or if the building is a confirmed roost). Dusk emergence surveys are carried out at night between May and September using specialist bat detection and recording equipment. If your site has potential as a hibernation roost, these surveys are carried out between December and February.

The aim of these surveys is firstly to establish the presence or likely absence of bats. If presence is confirmed, the surveys then determine the type of roost(s), species and approximate number of bats using it.

If your building is confirmed as a roost and will be impacted by your development proposals, it is likely that a mitigation plan will need to be devised, and a European Protected Mitigation Licence (EPSML) from Natural England applied for to allow the roost to be destroyed or modified.

Bat surveys are seasonal and cannot be conditioned, so all Phase 2 surveys will need to be completed before you submit your planning application.

Breakwell Ecology can help with all stages of bat survey, mitigation and licensing, guiding you through the process to ensure a positive outcome for both your project and bats. Get in touch now to plan your project around the bat survey season and prevent unexpected delays.