All 18 species of bat in the UK are protected by domestic and European legislation. This is why performing bat surveys thoroughly before starting any project is highly reccomended. Bats can roost in trees, buildings, caves, tunnels, bridges and other structures, as long as there is suitable habitat nearby for them to forage.

It is illegal to:

  • Disturb a bat or groups of bats in their roost
  • Damage or destroy a bat roosting place, even if there are no bats present at the time
  • Obstruct access to a bat roost
  • Capture, injure or kill a bat or possess, advertise, sell or exchange a bat, or part of a bat dead or alive

As bats regularly roost in buildings and trees, they can easily be affected by development or maintenance work.


Most bat surveys, such as dusk emergence/dawn re-entry surveys and activity transects, can only be undertaken between April and September when bats are active. However, internal and external building inspections and ground-level tree assessments can be undertaken at any time of year.

Hibernation roost checks can only be undertaken during the hibernation period from December to March, inclusive.

Our ecology consultants hold the relevant protected species licence for bats and have extensive experience of successfully delivering projects ranging from straight forward building extensions to major new housing schemes. ADAS also have trained tree climbers who can safely conduct climbed tree inspections for bats.

We also offer a bat genotyping DNA analysis service which can be ordered online.

Survey calendar

Bat surveys calendar

ecology survey legend

If bats are present

If found to be present and impacts to bats cannot be avoided, the applicable Statutory Nature Conservation Organisation (SNCO), e.g. Natural England will need to issue a European Protected Species mitigation licence to proceed with the development. Depending on how the roost will be impacted, this may include a requirement for the creation of replacement roosting opportunities, sensitive lighting strategies and creation of suitable foraging habitat.

Mitigation calendar

Ecological mitigation calendar for bats

* Please note if a European Protected Species Mitigation (EPSM) Licence is required, the process can take some time. It requires that recent survey work has been carried out at the site for this species. Survey work is seasonally constrained.