All 18 species of bats in the UK are protected by laws originating from European legislation. Both the bats and their roost sites are protected. It is illegal to kill, injury, capture or disturb a bat. It is also illegal to damage, destroy, or obstruct roosts.

Bats utilise a variety of places for roosting, breeding, foraging and hibernating. Developers need to be aware of the possible presence of bats on their land and the implications for development. They can roost in trees, buildings, or other types of structures. Roosts can vary in size from small cracks in trees and lifted roof tiles, to caves, tunnels and large attics.

Bat survey, assessment and mitigation work can involve the following:

• Daytime building searches (internal and external), which can be carried out any time of year, looking for roost features or possible roost features;
• Daytime ground based tree searches, which can be carried out any time of year, although winter is better due to less vegetation obscuring views, looking for roost features or possible roost features;
• Daytime aerial tree climbing surveys, which can be carried out any time of year, although winter is better due to less vegetation obscuring views, looking for roost features or possible roost features;
• If potential roost features are identified then night time activity emergence and/or re-entry surveys will be required – these are carried out around dawn and/or dusk, and timing can vary depending on the time of the year;
• Night time transect surveys, if it is suspected that bats are foraging or commuting on the site; and
• Bat mitigation activities, such as erecting artificial roosts and preparing various licenses.

The main period when it is appropriate to undertake bat activity surveys is mid-May to August; although, in line with guidance, a single additional survey can be carried out in early May or September.

To handle bats you must have an appropriate licence.

Almost any building or mature tree could be a potential bat roost. If you have these or other structures on your site that you might be concerned about then please contact us.

Phlorum can provide advice and carry out a range of bat surveys including preliminary roost assessments, dusk emergence surveys and pre-dawn re-entry surveys as well as static monitoring and bat activity transects. Our ecologists can also compile European Protected Species Mitigation (EPSM) licence applications for developments likely to impact upon bat roosts, or low impact bat licences which are sufficient on some sites.