Preliminary Bat Roost Assessment (PRA)
A daytime bat walkover survey, formally known as a preliminary bat roost assessment (PRA), is the first step in surveying for bats.
A Preliminary Bat Roost Assessment (PRA) can be undertaken at any time of year and involves a single daytime site visit. The survey includes an internal and external inspection of buildings, or a ground-based inspection of trees, to identify evidence of bat presence and assess the suitability of the structure or feature to support roosting bats. The assessment is carried out by one of our licensed ecologists.
The survey checks for signs of bat activity, including droppings, staining, carcasses, and other indicators, and assesses the site’s suitability, from negligible to high. A Preliminary Bat Roost Assessment (PRA) is an important first step in planning applications, helping determine if further nocturnal surveys are needed. It combines a desk study of local records with a daytime, on-site inspection. Buildings are examined for roof spaces, gable ends, hanging tiles, and slate roofs, while trees are checked for crevices or cavities. Our ecologist also looks for live bats, droppings, feeding remains, urine stains, and characteristic sounds or smells.
What's the best time of year for a PRA?
A PRA can be carried out at any time of year, making it a flexible first step in any bat survey process. It is often requested by local planning authorities to support planning applications, particularly for developments such as conversions, extensions, or demolitions. If no evidence of bats is found and the potential for roosting is low, no further surveys may be needed, saving time and costs. If potential roosting features are identified, additional surveys are usually required to ensure compliance with UK wildlife protection laws.
What’s the Difference Between a Preliminary Bat Roost Assessment and a Daytime Bat Walkover?
There is no practical difference between a Preliminary Bat Roost Assessment (PRA) and a Daytime Bat Walkover (DBW) survey. They refer to the same type of daytime bat survey.
The name changed to better describe what the survey involves. Daytime Bat Walkover clearly explains that the survey is carried out during the day and focuses on a visual inspection to assess the potential for bats, rather than confirming an active roost.
Both terms are still widely accepted by local planning authorities, and many ecologists now use them together to avoid confusion.
Based on the findings of the daytime bat walkover survey, we can ascertain if further bat emergence/re-entry surveys are required. Find out more about bat surveys.
To find out more about our daytime bat walkover survey or our full suite of ecology services, please browse:
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