The Bat Conservation Trust have just issued new guidelines for bat surveys. The key differences between the 2012 and 2016 guidelines are summarised below:
- Bat survey data will generally be regarded as valid for only one year.
- Bat emergence and re-entry surveys for structures and trees with low roost suitability now need to be completed between May and August, rather than May and September.
- The 2016 survey guidelines include a methodology for a Preliminary Ecological Appraisal for bats. This can be used alongside a standard Preliminary Ecological Appraisal for a site, but can also be used when this is not required, for example for an assessment of a single building or structure.
- The recommended survey effort for bat activity surveys has increased for some situations. Survey effort is no longer based on the size of a site, but simply on habitat quality. For this reason small sites are likely to require more surveys than under the 2012 guidelines. Furthermore, surveys need to be spread across the bat active season (April- October) and shouldn’t be undertaken close together.
- The 2016 guidelines recommend radio tracking and trapping techniques when surveying bats for major developments and where woodland habitats may be affected. Such survey methods require special licences and ecologists with expertise in these methods.