Case Studies

Bat Activity Surveys for Wind Energy Proposals – Nationwide

Client: Renewable Energy Developers

Between 2012 and 2015 our ecologists completed over 30 Extended Phase 1 Habitat surveys for proposed renewable energy projects throughout the UK, mostly wind turbine installations and ground-mounted solar arrays, many at existing farm holdings. Several sites featured habitats suitable for bats, including potential tree roosts, valuable feeding habitat, and hedgerows and other linear features which could be used by commuting and foraging bats. In several cases it was considered that a proposed turbine was in a position which could pose a significant risk to bats using these features. Further bat surveys were recommended in order to assess the levels of activity on site and establish what mitigation would be required to minimise the risk of impacts to individuals or the local population…

  • Our Clients

    We use Urban Edge Environmental for ecological appraisal services for our renewable energy projects across the UK, and have always found them extremely professional and able to meet tight timescales on site visits and reporting. More importantly, they are able to unpick complex ecological issues that allow a sensible route forwards for our developments. Thanks for all your help these last few years.

    Guy Manners-Spencer, Ecotec World Ltd
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Initial acoustic surveys were carried out using the following methods:

  • Static detectors were placed at height close to the proposed turbine location(s) and set to record for at least five continuous nights
  • Two ground-level transect surveys were undertaken using handheld detectors

The continuous monitoring data showed which species were passing through the site, and relative levels of activity throughout the night close to the proposed turbine location. Transect surveys provided further detail on the types of activity and location of any preferred foraging or roosting habitats, or commuting corridors.


Results from the initial surveys were used to determine whether a full season of bat survey data was required to properly assess the risk of impacts to bats. In some cases, where bat activity was particularly low or focused on a certain feature, it was sufficient to adjust the position of the turbine to avoid the risk of impacts (‘micro-siting’). Other outcomes have included:

  • Powys, Wales: Initial transects showed high levels of activity by both soprano and common pipistrelles throughout the site but particularly along boundary woodlands and hedgerows. Myotis bats and serotines were also recorded. Analysis of the static monitoring data showed that noctules and lesser horseshoe bats were present but in fewer numbers. Recommendations were made for a full season of bat surveys to build up a complete picture of bat activity on the site prior to exploring possible mitigation measures.
  • Norfolk, England: A full season of bat surveys found that common and soprano pipistrelle bats were foraging in moderate numbers within the site, but not were not at risk of turbine impacts. Noctule, serotine and Myotis bats were recorded in very low numbers, foraging outside the turbines’ zone of influence. It was concluded that the development could proceed with a minimal risk of impacts to individual bats or their local conservation status.
  • Lanarkshire, Scotland: Scoping surveys found relatively low levels of bat activity focused around tree lines at the site boundaries. A curtailment of operating conditions was agreed whereby the turbine would be switched off during the active season when the wind speed was suitable for bats to be flying, to avoid the possibility of impacts to bats occasionally foraging on site.

If you’re thinking of submitting an application for a site in your portfolio, and want to know the site’s ecological value or the implications for development, please contact us now.