Need help with a bat?

Follow our advice

or call us on 0345 1300 228

Artificial lighting

Bats are nocturnal animals and are adapted to low-light conditions. This means that most bat species can find artificial lighting to be very disturbing. Artificial lights shining on bat roosts, their access points and the flight paths away from the roost must always be avoided. 

Artificial lighting in the urban environment (K Gunnel)

If it is considered necessary to illuminate a building known to be used by roosting bats, the lights will need to be switched off at bat emergence time and during peak bat activity times. Or better still, it is usually straightforward to ensure that the light does not fall on the roost access point or the flight line away from the roost used by bats. Celebratory lighting of buildings should be limited to special occasions.

Bats and their roosts are all protected by law and bats should always be taken into account when lighting is being considered. 

BCT Interim Guidance: artificial lighting and wildlife

An interim guidance note has been produced following the outputs from the 2014 European Symposium detailed below. This will be updated to reflect research developments in this area, however it currently provides recommendations to help minimise the impact of artificial lighting.

Artificial Light and Wildlife Symposium 2014: determining solutions for practitioners

The Bat Conservation Trust in partnership with Arup hosted a European Symposium on 20 & 21 March 2014.

The syposium was fully described with presentations from researchers and professionals across Europe. The presentations from the symposium are now available to view online.

Unfortunately, some of the presentations cannot be circulated owing to the sensitivity of unpublished data contained within them. This data will be used to update the technical guidance note (above) in due course. 

Bats and Lighting: overview of current evidence and mitigation

BCT is working with researchers at the University of Bristol to develop a comprehensive overview of current evidence and mitigation for bats. This publication is now available.

Additional reference documents and websites:

What else are we doing?

Floodlit tree (Melvyn Taylor)As more bat workers have access to light meters, the National Bat Monitoring Programme colony counts now allow the opportunity to include information about the lux levels measured during bat emergence.



Those carrying out NBMP car surveys are being asked to record the type of street lighting along their route. All this data being gathered will be important in identifying trends that will support current research.


University of Bristol

Find out more

Guidance Notes for the Reduction of Obtrusive Light GN01:2011 (403 KB) - 23/04/12
Latest guidance note from the Institute of Lighting Professionals

RCEP Report on Artifical Light in the Environment (2 MB) - 23/04/12
RCEP report summarising environmental impacts of artificial lighting

Interim Guidance: Artificial lighting and wildlife - Recommendations to help minimise the impact of artificial lighting (559 KB) - 03/06/14
Interim Guidance: Artificial lighting and wildlife - Recommendations to help minimise the impact of artificial lighting









You should follow us
Bookmark and Share

Subscribe today to receive the latest on bats and BCT direct to your inbox.

Bat Helpline

0345 1300 228