We still have some availability for Bat emergence surveys - 01245 377440
Bat Roost Assessments
Preliminary Roost Assessments
The Preliminary Roost Assessment (PRA) is normally the first assessment undertaken on a structure to determine if bats and their roosts are ‘reasonably likely’ to be impacted by a proposed development.
The PRA has three main purposes:
- To categorise a structure for its suitability to be used as a roosting place for bats
- Record any evidence of bats that may be present
- Make recommendations on the surveys required to determine the presence or likely absence of bats or characterise the bat roost that has been recorded (see dusk emergence survey)
PRAs are normally undertaken at the planning stage of a development and they are commonly requested by Local Planning Authorities to support planning applications.
Permitted developments not requiring planning permission may also require a PRA for bats to be undertaken in order to demonstrate that appropriate care has been taken to avoid impacts to bats and their roosts before the commencement of a project.
Searching for signs of bats
A PRA consists of an external and, where safe to do so, an internal inspection of a structure. A search is undertaken to record any access points that could lead to internal voids or any gaps and crevices that could be used by roosting bats, often referred to as Potential Roosting Features (PRFs).
In addition, a search for signs of bats such as bat droppings, urine splashes and feeding remains, as well as bat specimens (live and dead) is undertaken.
Places that bats may use in buildings
Where in the building
In buildings a range of possible roosting opportunities exist that mimic those found in the natural environment. Crevice-like or tree cavity type spaces include those found in both modern and traditional houses such as behind fascia and barge boarding, behind hanging tiles and weather boarding, spaces beneath roof tiles, wall coatings, hollow mortice joints, rain gutters and chimneys. Cave-like spaces include attics and cellars that are dark, exhibiting stable temperatures and humidity. These spaces may be found in a range of buildings including barns and other farm buildings, historic buildings, castles, churches and terraced houses.
Bat Conservation Trust. (2012). Bats and Buildings. [Online]. Bat Conservation Trust.
Bat signs
Bats do not make nests or cause structural damage. The most obvious sign of their presence is droppings but even these can be hard to find. Bat droppings consist of insect remains and crumble easily between your fingers to a powder often containing shiny fragments. Rodent droppings are smooth and plastic, quickly becoming hard. They cannot be crumbled. Bat droppings are frequently mistaken for mouse droppings, so do the ‘crumble test’. Bat droppings do not present any known health hazards in the UK, but we suggest you wash your hands after handling any droppings. If you need to clean up a large number of droppings then consider wearing a dust mask. Droppings can be swept up safely to use as an excellent fertilizer in the garden. Large accumulations may reflect use over a number of years rather than large numbers of bats at any one time. Droppings may not always be readily visible in a loft. Other signs to look for are grease marks on the rafters, urine splashes, cobweb free corners, or insect remains from a feeding perch.
Frequently Asked Questions
Please reach us at office@ecologyessex.co.uk or give us a call on 01245 377 440 if you cannot find an answer to your question.
Bats are very cryptic animals that often coexist undetected unless targeted surveys are used to determine their presence. Local Planning Authorities are legally obligated to assess the impacts of protected species such as bats when considering a planning application. It is a requirement that an impartial and suitably qualified Bat Licenced Ecologist undertakes a Preliminary Roost Assessment to determine a building’s suitability for bats. As such, planning permission is unlikely to be granted without at least a PRA survey being undertaken on works to an existing building.
A Preliminary Roost Assessment is not a time-constrained survey and can be undertaken at any time of year. However, it is important to note that many of the additional surveys often recommended in PRA reports to determine presence or likely absence of, or characterise, a bat roost, are time constrained. Completing additional surveys at the correct time of year is likely to be a requirement to secure planning permission and bat mitigation licences (such as a European Protected Species Licence).
Example: Undertaking a PRA survey in September may mean that additional bat surveys are required to demonstrate that a proportionate survey effort has been made and to determine the presence or likely absence of bats. If all dusk emergence surveys are completed after September, the survey effort may not be accepted by the Local Planning Authority or Natural England, as this does not provide the correct coverage of the bat survey season. In this scenario it would be better to wait until the following May to complete the surveys.
It may be possible to secure planning permission with just a PRA survey if a building is categorised as having negligible suitability for roosting bats during a PRA survey. If a building has any potential roosting features present, in almost all circumstances, further dusk emergence surveys to determine the presence/likely absence of bats will be required by Local Planning Authorities. In line with biodiversity and geological conservation: circular 06/2005, further dusk emergence surveys should be completed prior to submitting a planning application and should not be conditions of planning.
Tel: 01245 377 440
Tel: 01245 377 440
Tel: 01245 377 440
Tel: 01245 377 440
Tel: 01245 377 440
Tel: 01245 377 440
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