The Bat Mitigation Guidelines reflect the significant changes in our understanding of bat ecology and mitigation practice since the publication of English Nature’s (now Natural England’s) Bat Mitigation Guidelines (Mitchell-Jones, 2004). They have been produced by synthesising the most up-to-date research evidence available at this time and the expertise of bat ecologists drawing on decades of experience. That they have been almost five years in the drafting reflects both the extensive amount of additional information available and the complexities of delivering successful bat mitigation and compensation. It also highlights the dedication and huge time commitment volunteered by the authors, supported by the steering group and all those who responded in detail during the consultation phase.

As practitioners, you can help us to develop the evidence base for future editions by monitoring and recording the outcomes of projects you have been involved in and sharing your successes and failures. You can submit your case study examples of project design, novel approaches and outcomes using this form.

If you have spotted a correction or amendment that needs to be made, please contact us by submitting this form.

Similarly, if you come across research papers, reports, articles or references that highlight new evidence regarding effective bat mitigation techniques, please bring these to our attention using this form.

Please note that the guidelines were first published in 2023. In August 2025, the Review Group published this version 1.2 which features several small amendments in relation to the timing of works, particularly around winter working and the risk of hibernating bats, principally in non-classic sites. There are three new case studies, and an update to an existing case study. There are also a few small research and guidance updates; changes are listed on page 9.

This document should be referenced as:

Reason, P.F. and Wray, S. (2025). UK Bat Mitigation Guidelines: a guide to impact assessment, mitigation and compensation for developments affecting bats. Version 1.2. Chartered Institute of Ecology and Environmental Management, Ampfield.