New Bat Survey Guidelines - Changes that Affect You

Posted by Ecosulis Consulting Team on 3/02/2016
The Third Edition of the Bat Conservation Trust Good Practice Guidelines (sponsored by Ecosulis) have just been released. Here is an overview of what you need to know, and how it may affect your upcoming projects.


Bat surveys are usually required to inform planning applications for the site, and range from roost emergence/swarming surveys to bat activity surveys.

The key changes within the guidelines include:


  • New Preliminary Ecological Appraisal for Bats
  • Alignment with the British Standards BS42020 for Biodiversity (2013) that recommends a proportionate approach
  • Bat Activity Surveys – the recommended survey scope has increased, with more activity surveys required over the survey season. This could result in delays to your programme if not accounted for early in the project
  • Survey data should be 12 months old or less to support planning
  • Radio Tracking and Trapping requirements likely to increase

Further details are provided below, alternatively please contact us with any queries.

Preliminary Ecological Appraisal for Bats

The 2016 Bat Survey Guidelines have included a new chapter on Preliminary Ecological Appraisals for bats which references and expands on the CIEEM Guidelines for Preliminary Ecological Appraisal (2013) that recommends an initial assessment of structures for bats, and should consider potential impacts on populations both on and off site.

Schemes will increasingly need to consider the Zone of Influence and the Core Sustenance Zones of species likely to be present which may need to extend up to 10km for larger projects. This could have larger impacts on mitigation requirements for your scheme and must be considered early in the design phase.

Bat Activity Surveys

Activity surveys are a key method used to assess the use of a site and identify any key habitat features. Generally these surveys are undertaken during the summer survey season between April and October and are supported with static bat detectors that can collect a larger data set over a longer period of time. In terms of undertaking these surveys the guidelines bring some changes, many of these will have minimal impact on projects and instead provide further guidance on methodology.

However a crucial change within the new guidance is an increase in the recommended survey effort for bat activity surveys. For sites that provide low suitability for foraging and commuting habitat, at least three surveys are required, with one conducted per season (spring, summer and autumn). The survey effort then increases for higher quality habitat for bats. The guidelines are prefaced with the need for proportionality throughout the process and as such are subject to professional judgement. These changes make it more important than ever to consider bat surveys as early as possible within your projects lifecycle to minimize the risk of delays. In addition, the guidelines recommend statistical analysis for large projects/data sets to provide further assessment of significant impacts.

Bat Roost Inspections – Trees

Tree inspections are required if proposals could directly impact (through felling/pruning) or indirectly impact (increased lighting) potential roosting features. Trees can be very difficult to survey for suitable roosting features, particularly during the summer months when leaf levels are high. A Preliminary Ground Level Tree Assessment usually needs to be complimented with a climb and inspect survey, which can provide more accurate information. Alternatively, if woodland habitats are likely to be significantly affected, Advance Licence Bat Survey Techniques may be required, such as trapping and radio tracking.

Radio Tracking and Trapping

Radio tracking and trapping have been used previously for large scale developments, particularly those that may affect Annex II species using a woodland (such as Bechstein bats). However, the 2016 guidelines put more emphasis on the use of this technique for large scale developments, and is likely to be increasingly used in the future. The techniques can be intrusive, especially for sensitive bats, therefore must be proportionate to the impacts and the species to be considered, and undertaken in combination with other survey methods. These surveys require specialist licenced and experienced bat ecologists.

Ecological Considerations for Bats

This section, previously named ‘Considerations for Consultant Ecologists Working on Bats’, focused on the surveyors and their skill levels, experience and licences. Within the 2016 Bat Survey Guidelines the section is renamed and provides much more insight into the life cycle of bats, roost types and emergence timings. All of which give the you much more insight into reasons behind surveys, as well as, a clearer understanding of bat survey requirements.

The section also goes one step further and explains species specific limitations and considerations. These include roost preferences, foraging habitat preferences, core sustenance zones, as well as the number of surveys required to achieve 95% of the certainty of detection. The guidelines outline the behaviours of each bat species and identify the best survey method to ensure detection, including the most effective equipment. This section also outlines what information you should expect from bat surveyors supply and why this is a fundamental factor to inform mitigation requirements and your planning application.