All bat species in the UK are protected under the Conservation of Habitats and Species Regulations 2017 and the Wildlife and Countryside Act 1981 (as amended). Under this legislation, it is an offence to capture, kill, injure or disturb a bat, or obstruct, damage or destroy their breeding or resting place (roost). All bat species are Priority Species under the UK Biodiversity Action Plan (UK BAP), now adopted as Species of Principal Importance in England under Section 41 of the NERC Act 2006.
The first stage of survey for bats is a Preliminary Roost Assessment. This comprises an inspection of a structure or building (internally and externally) to assess its suitability for roosting bats. The favourability of the surrounding habitat and connective landscape would also be considered.
A Preliminary Roost Assessment of a building or structure can be undertaken at any time of the year.
Inspections at certain times of the year have an advantage; an inspection in the winter months can help determine with greater certainty if a structure is used by hibernating bats, whilst an inspection in the spring or summer would be more helpful in assessment of the use of a structure or building by bats during their active season.
Do bear in mind, however, that a reliable conclusion about the use (or otherwise) of a building or structure by bats may not be achievable upon the basis of this initial inspection alone. If it is not possible to confirm likely absence or negligible suitability for roosting bats at the time of survey, additional inspections at different times of the year, or emergence, or activity survey work for bats may be required.
Bat emergence surveys are undertaken to determine the presence / absence of bat roosts within a building or structure. Bat emergence surveys are restricted to a time of year when bats are active (May – September, ideally June – July). Bat activity surveys may be undertaken between May – October, depending upon the data requirements of a project. They enable assessment of how bats are using a site and which species are present.
There is a high occurrence of bat roosts in trees as this is their primary roost habitat.
The first stage of assessing the suitability of a tree or trees for roosting bats is a Preliminary Ground Level Roost Assessment.
Trees are assessed for their suitability for bats based upon the occurrence of Potential Roost Features (PRFs), which include rot holes, branch tears, hazard beams and woodpecker holes to name a few.
PRF Inspection Surveys, which often involves aerial inspections (tree-climbing), are undertaken where required to assess the likelihood that the features are used by bats and to look for field signs.
Tree climbing surveys and inspection are often a very effective way to determine use of a tree by bats and can also be quicker and more cost-effective than emergence surveys of trees.
Following a Ground Level Roost Assessment, an aerial inspection is used to determine the suitability of Potential Roost Features for bats. Aerial inspection is a much faster and more effective way of reclassifying trees than using alternative methods like emergence surveys.
We have surveyors qualified to climb trees and inspect features to determine their suitability for bats.
The level of survey and the design of a survey for bats or any other protected species will depend upon the specifics of the project concerned. We are innovative with our approach to ensure that we gain robust, reliable data that will support and inform the project findings sufficiently, whilst ensuring the work is proportional to the proposals and associated risks.
If a building, structure or tree supports a bat roost and the proposed works may impact that roost then it may be necessary to obtain a European Protected Species Mitigation (EPSM) Licence prior to the start of the works.
If it is necessary to obtained an EPSM licence for bats in order for the work to go ahead we can assist with the mitigation strategy, produce the necessary documentation for submission and see the licence through until project completion.
An EPSM licence application requires up-to-date survey work.
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