PRA/Phase 1 Bat Survey

We specialise in bat surveys and follow the professional training standards for bat Ecologists as set out by the Bat Conservation Trust. Contact us to learn more about our vision and approach.

A phase 1 survey is the first step to conducting a bat survey.

PRA/Phase 1 Bat Survey

In the UK, a Preliminary Roost Assessment (PRA) is an initial survey carried out to determine the potential presence of bats within a building, structure, or tree. This is often the first stage in the bat survey process and is typically required when a proposed development may affect features that could provide bat roosting opportunities.

Purpose of a Preliminary Roost Assessment

The main objectives of a PRA are to:

Assess the likelihood that a building, structure, or tree supports bat roosts.
Identify potential access points, roosting features, and signs of bat activity.
Determine whether further (Phase 2) bat surveys are needed.
Provide early advice on potential ecological constraints to development.

Methods Used in Preliminary Roost Assessments

PRAs are desk- and field-based studies carried out by qualified licensed ecologists. They typically involve:

Stage 1 – Desk Study

Review of local biological records, designated sites, and previous survey information.
Assessment of the wider landscape for habitats suitable for foraging and commuting.

Stage 2 – Field Inspection

External and internal inspections of buildings and structures for features such as cracks, gaps, or cavities that could be used by bats.
Inspection of trees for features such as holes, loose bark, and splits that could provide roost opportunities.
Use of ladders, torches, endoscopes, and occasionally thermal imaging to assist in inspections.
Recording any direct evidence of bats such as droppings, feeding remains, urine staining, or audible calls.