WHAT IS A PRELIMINARY BAT ROOST ASSESSMENT?

A preliminary bat roost assessment is an essential step in the ecological survey process, particularly in the context of planning applications in the United Kingdom. It involves an assessment of the potential presence of bat roosts within or in close proximity to a proposed development site.

Bats are protected under both domestic and European legislation due to their declining populations and ecological significance. In the UK, they are safeguarded by the Wildlife and Countryside Act 1981 (as amended) and the Conservation of Habitats and Species Regulations 2017. These legal frameworks require developers to consider the impact of their projects on bats and their roosts.

The purpose of a preliminary bat roost assessment is to identify the likelihood of bats using a site for roosting and to determine if further surveys are necessary. It typically involves a combination of desk-based research, site inspections, and data analysis. Factors such as the presence of suitable habitat, roosting features (e.g., trees, buildings), and foraging opportunities are evaluated to assess the potential for bat activity.

A preliminary bat roost assessment is necessary to support a planning application in the UK for several reasons. Firstly, it ensures compliance with legal obligations by demonstrating that the impact on bats has been appropriately considered. Secondly, it provides valuable information to inform the design and layout of the proposed development, allowing for the incorporation of measures to minimise harm to bats and their roosts. Lastly, it helps establish a baseline understanding of bat populations in the area, aiding long-term conservation efforts.

WHAT ARE BAT ACTIVITY SURVEYS?

Conducted at dusk (BCT 2023) and restricted between the months of May to September inclusive, bat activity surveys (BAS) are sometimes required where bats, evidence of bats or habitat value is present at your site.

Most people are unaware they are sharing their home with bats.  The most common species in the U.K. are crevice-dwelling bats, which exploit some cracks and crevices in your property, such as damaged flashing or cracked and slipped roof tiles.

If your PRA identifies bat potential, you will need further BAS surveys.  This does not mean that evidence of bats or their habitats on your site will stop you from obtaining planning consent.  It does mean, though, your local planning authority (LPA) will need to see evidence (a report) that proves appropriate steps have been taken to mitigate the project's impacts to bats in a way that avoids any activity that could potentially intentionally kill, injure or endanger bats if evidence is found on site.

The general perception is that activity surveys are simply a cash cow for ecologists; this is as far from the truth as possible.  At ROAVR, we pride ourselves on being upfront and honest about what survey effort is likely to be required at your site.  Sometimes we can even tell this from an initial desktop assessment of the photos you provide us and the information in publicly available records. 

Once it is established that a BAS survey is necessary, an ecologist will visit the site and monitor the entry and exit points to gather information on the UK bat species, location and population. The data gathered from this exercise will be used to gauge the presence of bats on the site as well as the effect bats may experience as a result of the permitted development work.

WHEN IS THE BAT ACTIVITY SURVEY SEASON?

As with any legally protected species surveys, bats are protected under certain national and European legislation, and restrictions are in place as a legal requirement based on the specific bat activity, behaviours and hibernation patterns of the species in question. Due to this approach, the bat survey season will take place outside of bat hibernation.

Bats hibernate between November and March, meaning that it is only possible to carry out BAS at a certain time of the year between the months of April and October. However, the optimal period lies in the summer months between May and September, with at least one survey visit taking place in the peak of activity between May and August. The BCT publication ‘Bat Surveys for Professional Ecologists Guidelines – Good Practice Guidelines’ (2023) insists that Activity Surveys are solely conducted within this time.

Within full bat survey guidelines from the BCT and rules enforcing legal compliance, Activity Surveys must be conducted outside of daylight hours and solely around sunrise and sunset. 

Stage two surveys on nocturnal animals such as bats are undertaken 15 minutes before to two hours after sunset, or two hours before to 15 minutes after sunrise.

The cost of a Bat Activity Survey can be variable and depends on a number of factors. For an accurate quote, contact Lucy or Karalyn at ROAVR for a discussion about your specific needs, even if you have had your preliminary survey done elsewhere - we can help.