Preliminary Bat Roost Assessment

A preliminary bat roost assessment should be undertaken at the start of a project whereby a structure, tree or habitat feature is likely to be impacted by the proposed works. This assessment will coincide with a desk study which aims to collate and review existing information about a site and its surroundings. Ecological records will be reviewed to establish the presence of any known roosting bats in the local area. Following the desk study, a field visit will be undertaken by our experienced ecologists to assess the suitability of the structure or habitat feature for bats.

The survey will assess and record any habitats suitable for bats to roost, commute and forage both on site, within the structures/trees and in the surrounding area. The aim of this survey is to determine the overall suitability of the site for bats and to assess whether further bat activity surveys will be required.

For structures, both an internal and external survey should be undertaken. This may include a search of any loft voids, boiler rooms and cellars. Access points in to the building will be noted and any signs of bats will be documented. If bat droppings are found, we are able to send these off for species identification through eDNA.

Preliminary bat roost assessments for trees are often most conclusive when undertaken via aerial inspection. Features suitable for roosting bats can often be difficult to assess from ground level or by ladder; aerial inspection can be useful for ruling out features which may prove to be superficial once under a close inspection. Our qualified tree climbers are well versed in carrying out aerial inspections.

The outcome of this type of assessment for structures (or parts of) and trees provides a suitability category for roosting bats of negligible, low, medium or high. Negligible suitability means that no further bat surveys are required and your planning application can proceed with respect to bats. Low, medium and high categories generally require one, two or three bat activity surveys respectively to establish the presence/absence of bats and provide an assessment of roost size should bats be noted. Further information on bat activity surveys can be found here.