Bat Surveys and Assessments

Crestwood has extensive experience in undertaking all aspects of bat surveys. All surveys are carried out by Class 1 and Class 2 Bat Licenced surveyors.

Our bat surveys include:

  • Preliminary Bat Roost Assessment (‘PRA’);
  • Walked Activity Transect Surveys (including Automated Surveys);
  • Emergence / Re-entry Surveys; and
  • Bat sonogram analysis.

Preliminary Bat Roost Assessment (‘PRA’)

An external / internal visual assessment of buildings and / or trees at a site. Structures are inspected from ground level recording any evidence of bat roosts, droppings, staining, scratch marks and feeding remains etc.

A Preliminary Roost Assessment (‘PRA’) for bats should always be carried out before any development works commence on buildings, structures or trees to identify any actual or potential sites for bat roosts in order to ensure compliance with relevant legislation.

Emergence / Re-entry Surveys

Bat roost surveys are normally carried out before any demolition works commence. The aim of the survey is to determine the presence / likely absence of roosting bats within a building, structure or tree. The peak survey period is between May and August, the number of surveys depend on the suitability of the structure.

Walked Activity Transect Surveys

Walked transects carried out between April and October on open sites prior to commencement of development to determine the intensity, type and location of bat activity at a site. The habitat suitability is determined based on industry standard guidance and including the use of static bat detectors to collect additional sound data for analysis.

Bat Sonogram Analysis

Bat calls recorded using static bat detectors placed at the site (as part of Walked Activity Transect Surveys) are analysed by experienced ecologists using appropriate software.

Bat Mitigation and Licensing

Crestwood has experience in design and implementation of bat mitigation strategies including bat boxes, Sensitive Lighting Schemes, bat lofts for brown long-eared bats, and preparation of European Protected Species (EPS) mitigation licenses. Our ecologists provide Ecological Clerk of Works (ECoW) in line with appropriate method statements for demolition of buildings and tree works which have been identified as suitable for roosting bats.


If you would like to contact us about these services – please visit our contact page here.

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