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Bat Surveys

British Bats

There are 17 resident species of bat in the UK, with the greatest number of bat species being concentrated in the south-west of England. All of the British bats are insectivores, mostly eating flying invertebrates or invertebrates that can be picked off vegetation.

Bat Legal Status

All UK bat species and their roosts are protected under UK and European law, with a penalty of 6 months imprisonment or an unlimited fine for committing an offence.

Bat Surveys

There are a range of bat surveys that can be undertaken, depending on your need and the scope of your project, including bat activity surveys, bat roost emergence surveys, bat hibernation surveys, daytime bat inspections, and aerial bat tree inspections.

Licensing and Mitigation

In order to permit a development in a building or on a site that has a bat roost, a development licence from the statutory nature conservation organisation (such as Natural England) will be required.

In this instance, a mitigation plan will be needed to ensure that the favourable conservation status of the bat species is not significantly impacted.

Case Study: 

SK Environmental Solutions Limited undertook a program of emergency surveys after bats had been found within the building during some routine repair works. Find out how we dealt with it........

British Bats

There are 17 species of resident bats in the UK. Although other species are sometimes recorded within the country, they are unlikely to breed here. The main concentration of species is found within the south-west, with all of the 17 species being found in counties such as Hampshire and Dorset.

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  • Alcathoe bat - Myotis alcathoe

  • Barbastelle bat - Barbastella barbastellus

  • Bechstein's bat - Myotis bechsteini

  • Brandt's bat - Myotis brandtii

  • Brown long-eared bat - Plecotus auritus

  • Common pipistrelle - Pipistrellus pipistrellus

  • Daubenton's bat - Myotis daubentoni

  • Greater horseshoe bat - Rhinolophus ferrumequinum

  • Grey long-eared bat - Myotis austriacus

  • Leisler's bat - Nyctalus leisleri

  • Lesser horseshoe bat - Rhinolophus hipposideros

  • Nathusius' pipistrelle - Pipistrellus nathusii

  • Natterer's bat - Myotis nattereri

  • Noctule bat - Nyctalus noctula

  • Serotine - Eptesicus serotinus

  • Soprano pipistrelle - Pipistrellus pygmaeus

  • Whiskered bat - Myotis mystacinus

All of the UK species of bat are insectivorous, eating insects and small invertebrates which they catch either in mid-air or by picking them off vegetation and foliage. As such, they are considered to be a relatively valuable biological control of some pest insects, including mosquitoes and midges (of which even a small bat, such as a pipistrelle, can eat several thousand in one night!).

Bats roost in two main locations; buildings and trees. Some species have almost entirely converted their habitat selection to suit roosting in houses and other buildings. Roosting in buildings occurs in two types of location; crevices and open roosts. Crevice roosts, from bats such as pipistrelle and Myotis bats, can be under roofing slates and tiles, in gaps in the walls or behind damaged fascia boards and other such cladding. Despite this, bats never open up locations and will not chew a opening like a rodent might do. Open roosting bats can be found in loft spaces, open barns, or other such disused buildings. These bats, which include long-eared bats and horseshoe bats, are often more obvious, being openly visible as well as leaving tell-tale piles of dry droppings.

Our licensed bat ecologists are very experienced and well trained at both carrying out bat surveys and providing objective advise on mitigation and licensing.

Bat tree roosts, although often overlooked, are common within certain habitats and are not restricted to large veteran trees. Where a development is likely to affect trees, it is important to assess the trees for bat roost potential, so as to avoid committing and inadvertent wildlife crime by felling a bat roost. SK Environmental Solutions have experienced and bat licensed tree climbers who can assess a tree for it's bat potential prior to any works commencing. Find out more here

British Bat Legal Status

All British bats are protected under British and European law. They are listed on Appendix II of the Bern Convention and on Annexes II and IV of the EU Natural Habitats Directive, making them a European Protected Species, similar to great-crested newts, otters and dormice. 


In England and Wales, they are covered under the Wildlife and Countryside Act (1981) (as amended), the Countryside and Rights of Way Act, 2000, the Natural Environment and Rural Communities Act (NERC, 2006), and by the Conservation of Habitats and Species Regulations (2010).

In Scotland, they are protected by the Conservation (Natural Habitats &c.) Regulations 1994 (as amended), while in Northern Ireland bats are listed under Schedule 2 of the Conservation (Natural Habitats etc) Regulations (Northern Ireland) 1995.


Under these pieces of legislation it is an offence to:

  • Deliberately capture, injure or kill a bat

  • Intentionally or recklessly disturb a bat in its roost or deliberately disturb a group of bats

  • Damage or destroy a bat roosting place (even if bats are not occupying the roost at the time)

  • Possess or advertise/sell/exchange a bat (dead or alive) or any part of a bat

  • Intentionally or recklessly obstruct access to a bat roost

These laws apply to a bat roost whether the bat(s) are present or not; this is so that their roosts are protected while they are in hibernation over the winter. Similar to great-crested newts, breaking these laws is classed as an 'Absolute Offence'. This means that if an offence is committed, the person can be found guilty by the act alone, even if he/she had no intention. Essentially, negligence is not an excuse and there is no requirement for the prosecution to establish intent or fault.

This highlights the importance of carrying out bat surveys in advance of a project so that offences are not accidentally committed by well-meaning developers who have not established the status of bats on a site. 

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Bat Surveys

The type of bat survey undertaken depends on the habitat on site and extent of the development. The standard of survey effort is detailed in the Bat Surveys for Professional Ecologists: Good Practice Guidelines (3rd edition), issued by the Bat Conservation Trust;

Building Bat Inspection

These surveys start with a building inspection, during which an experienced SK Environmental Solutions bat ecologist will inspect the building for bats and evidence of bats. In addition, they will assess the site for potential to support bats and accommodate a bat roost. If evidence of bats is found, or if the property has potential to support bats, then further survey work is likely to be required, in the form of summer bat activity surveys.

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Summer Bat Activity Surveys

If a property has potential for bats then night-time bat surveys will be required. During these surveys, a team of bat surveyors will monitor a building at dusk or dawn to watch for emerging or re-entering bats, using roosts within the building. SK Environmental Solutions use the latest technology for these surveys, including specialist full-spectrum bat detectors, infrared cameras and static bat detectors, which can be left on site for extended periods to monitor activity remotely.


These surveys can only be carried out when bats are at their most active, which is between May and September. However, the peak season is June to August and surveys should not be conducted solely during May or September.

From these surveys, our bat ecologists can pinpoint any bat roosts on site, including identifying the species and the estimated roost population. We will then provide pragmatic advice to ensure that the development can progress with the least impact to the works schedule and to the bat population itself.

Transect Bat Surveys

For sites that do not feature any buildings, but will impact on the landscape or habitats that bats might use then a transect bat survey may be required. This type of survey involves SK  Environmental Solutions bat ecologists walking a set route around a site, with bat detectors and recording the bat activity on site. These surveys are usually paired with the use of static bat detectors that can be left on site for extended periods to monitor the activity. 

From these surveys, our ecologists can establish the use of a site by bats and therefore provide suitable advice to mitigate for the potential impacts to local bat population.

Aerial Tree Assessments for Bats

See Woodland and Trees section

Bat Licensing and Mitigation

Work which would have a significant negative impact on the welfare or favourable conservation status of any individual or population of bats, will require a European Protected Species development licence from the Statutory Nature Conservation Organisation (Natural England, Scottish Natural Heritage, Natural Resources Wales or Northern Ireland Environment Agency).

In order for the relevant SNCO to issue the EPS licence, the relevant SNCO would need to be provided with sufficient evidence that the development is necessary, either through ‘Preserving public health or public safety‘ or for ‘Imperative reasons of overriding public interest‘.

As part of the application, which is usually handled by your ecologist, a bat mitigation plan or method statement must be produced. SK Environmental Solutions are very experienced in producing these statements and brokering a compromise so that developments can progress with minimal disruption to both the project and to the bats involved.

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Bat mitigation

SK Environmental Solutions can provide EPSM licences as well as Bat Low Impact Licences. The latter is a recent licence format that is can be applied for at sites where there are low numbers of common species of bats on site. These licences are quicker and cheaper than EPSM licences. However, they cannot be usedat all sites.

Mitigation may include timing of the works to coincide with the period of lowest disturbance to bats (usually early spring or autumn), providing replacement roost locations (such as bat boxes, bat lofts or artificial crevices) or habitat enhancement. It is actually relatively rare that bats are excluded from a property without providing replacement roosting habitat. 

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