If a site is assessed as having low to high foraging and commuting value for bat species, there may a requirement to undertake a minimum of three surveys to determine levels of bat activity, referred to as night-time bat walkover surveys.

Night-time bat walkover surveys commence at sunset and continue for up to two hours after sunset. For the first 30 to 60 minutes of the survey, surveyors will be positioned at fixed vantage points to observe activity. A pre-defined transect route will then be walked through the site.  Bat activity including behaviour, flight direction, species and number of bats will be recorded.

These surveys will be supplemented with automated static bat detector monitoring. Remote bat detectors are deployed for at least 5 consecutive nights of suitable weather conditions per season (spring, summer, autumn) or each month (April - October) depending on the suitability of the site.

All surveys are undertaken in line with the 2023 Bat Surveys for Professional Ecologists: Good Practice Guidelines (4th edition). The Bat Conservation Trust