Updated Terminology for Bat Surveys

The words for bat surveys have been changed due to updates to the guidelines. Here’s our guide to understanding the new terminology coming from your ecologists:

• Daytime Bat Walkover (DBW) – preliminary assessment for suitability of buildings/structures for bat roosts and habitats for foraging bats, undertaken alongside Phase 1 /preliminary ecological survey
• Ground Level Tree Assessment (GTLA) –inspection of the exterior of the tree for Potential Roosting Features (PRFs). New guidelines have replaced negligible, low, moderate, or high suitability with:
• NONE (no PRFs present or unlikely)
  – FAR (further assessment required to establish if PRFs are present)
  – PRF (at least one PRF present)
  – PRF Inspection Surveys (trees) – tree-climbing or use of access equipment to allow a more detailed inspection of PRFs and their suitability for bats.
• Presence/likely absence surveys – replace the term ‘emergence survey’ and are still required on buildings/structures.
• Roost Characterisation Surveys (RCS) – same method as presence/likely absence surveys, triggered for buildings and trees.
• Night-time Bat Walkover (NBW) Surveys – replaced the term ‘bat transect/activity surveys’, involves surveying up to one hour after sunset in one location (on potential flight lines close to potential roost sources) and then surveying a pre-determined route.

Access a copy of the Bat Conservation Trust guidelines here.