Daytime Bat Walkover

Background

All bat species and their roosts receive protection under UK and European legislation. This legislation makes it illegal to; intentionally or deliberately take, kill or injure a bat; damage, destroy or obstruct access to bat roosts; deliberately disturb bats.

A bat roost is defined in the legislation as “any structure or place which a bat uses for shelter or protection”. Roosts are protected whether or not bats are present at the time. If a development activity is likely to result in the disturbance or killing of a bat, damage to its habitat or any of the other activities listed above, then a licence will usually be required from Natural England. Bat roosts can be present within trees, buildings, and other structures such as bridges.

EMEC Ecology carries out bat surveys for projects at a range of scales, including large public and private sector projects, and small residential development sites including re-roofing and home extension projects. A Daytime Bat Walkover (DBW) for bats is normally the first step in determining whether planned works are likely to negatively impact bats.

Timing

Daytime Bat Walkovers can be conducted at any time of year; however, the optimal time of year for this type of assessment on trees is during winter, when vegetation is less likely to obscure features. Should further bat surveys be required, these can only be carried out during the appropriate bat survey season (May to September, inclusive; with most of the surveys undertaken within the optimal season of May to August, inclusive for “summer” roosts), and hibernation surveys can only be undertaken over winter (November to March, inclusive). If multiple further bat surveys are required, these should be spaced at least three weeks apart.

Methodology

A Daytime Bat Walkover involves a survey of the built-structures and trees to be affected, looking for signs of bats such as droppings, feeding remains, scratch marks, urine stains, and actual sightings of bats, as well as potential access points and roost sites such as holes, cracks and crevices. The habitat on site will also be assessed for its potential to support foraging and commuting bats.

Following the Survey

We will provide a report detailing the survey methodology and results and recommendation for general mitigation measures, further surveys and/or consultation and licensing requirements, as appropriate. The report will be provided as soon as possible following the survey, however; should you have a specific date for submission of a planning application we will do our utmost to accommodate this.

Should evidence of bats be found or areas suited to roosting bats identified, it may be necessary to complete further surveys, comprising evening emergence surveys and / or aerial inspections of trees. These further bat surveys allow for identification of roost access points, number of bats present, species of bat using a roost and characterisation of the roost. Should a built-structure or tree be suitable for hibernating bats, hibernation surveys may be required over winter, which would involve a licensed bat Ecologist searching for hibernating bats during a daytime survey, and the deployment of static bat detectors for the entire hibernation period (November to March).

Should the site provide suitable features for bats swarming during the autumn, swarming surveys may be required between mid-August and October inclusive to understand how bats use the site.

Should habitat on site be suitable for foraging and / or commuting bats, it may be necessary to complete bat activity surveys. These surveys would involve recording bat activity along a walked transect at dusk or dusk-dawn in addition to using automated static detectors at fixed locations.

Information regarding further bat surveys can be found here: