How are bat surveys done?

Bats are secretive animals and a great deal is still unknown about their habits and behaviour. The fact that they fly at night, make sounds which we are unable to hear and leave almost no clues to indicate their presence make surveying for them a highly skilled practice. We rely on experience and the latest technology to make sure that the results we produce are accurate reliable and up to the standard required by Natural England.
UES can provide a full spectrum of bat related advice, survey work, reports, Licence applications, mitigation and habitat / roost creation.

Bat Surveys

Why carry out bat surveys?

Bats are susceptible to changes in their environment and their numbers have decreased dramatically over the last century. Changes in agricultural practices, the loss of woodlands and hedgerows and the expansion of our towns and cities, have taken valuable habitat from our native bat species. As a result of this bats have become protected by UK and European legislation.
Any action or development which has the potential to impact on bats or their habitats must be carried out under a European Protected Species (EPS) licence issued by Natural England.
Before a licence can be issued Natural England need up to date information on the type and number of bats which will be affected, how the bats use the site and what impact your development will have on any bats using the area. The only way to gain this information is by carrying out thorough bat surveys.

What type of survey do I need?

The type of bat survey required will depend on your individual project; a large rural or offshore wind farm will need a different type of survey and a different level of survey effort than a barn conversion or a loft conversion in an urban centre. Some sites may only need a small number of observers while larger sites or more complicated structures may require more people to effectively cover the ground. Some of the most commonly used survey methods are:

• Bat scoping survey
• Bat presence / absence survey
• Bat activity survey
• Bat roost survey

These are explained in more detail below. Contact us for further information and advice.

Bat scoping surveys are used to initially assess an area and check the general suitability of the habitat for use by bats. In some circumstances this can give you a quick indication that the building or area is not suitable for use by bats, and allow your project to continue without the need for any further survey work or a Natural England EPS licence. If the area is considered suitable for use by bats then more thorough survey work must be undertaken.

A bat scoping survey will involve a site visit to check for habitat features and field signs which are associated with bats. A report with any findings and recommendations, together with photographs, GIS mapping and aerial photography will be produced to support your application. Bat scoping surveys can be done throughout the year.

Bat presence /absence surveys are used to confirm whether bats are using a building or area which is broadly suitable for bats. Methods can include:

• Search of any internal roof spaces for signs of presence or use
• Search of external building features which could be used by bats
• Search of any habitat features such as holes in trees
• Bat emergence survey (waiting for bats to emerge from a roost)
• Bat return roost survey (waiting for bats to return into a roost)
• Bat activity survey to assess how many bats are using the area and in what way

A report detailing any findings and recommendations will be produced together with photographs, GIS mapping and aerial photography to illustrate how bats are using the site. Bat presence /absence surveys can only be done at times of the year when bats are active.

Bat activity surveys are used to record the level and type of activity at a site which is used by bats and also to record the type of species present. The surveys usually involve a number of site visits in suitable weather conditions in order to determine the areas which are used by bats, how those areas are used and indicate the range of species and number of bats using the area.

A report detailing any findings and recommendations will be produced together with photographs, GIS mapping and aerial photography to illustrate how bats are using the site. Bat activity surveys can only be done at times of the year when bats are active.

Bat roost surveys are used to check the interior of a tree, building or structure for signs of bat presence. Methods typically include a thorough inspection of the structure looking for:

• Gaps which are suitable for bats to gain entry
• Droppings and urine staining
• Scratch marks and polished areas on wooden boards and beams
• Evidence of feeding remains
• Bat presence

Often people in the area may have seen bats using the area or the structure in question.
A report detailing any findings and recommendations will be produced together with photographs, GIS mapping and aerial photography to show the areas which have signs of bat use. Bat roost surveys can be carried out throughout the year.

Contact us for advice prior to the start of your project.

More information

The Bat Conservation Trust (BCT) is a charity that does a lot of good work for the conservation of bats. They organise and run lots of projects with the aim of creating better habitats for bats. For more information visit the Bat Conservation Trust (BCT) website. http://www.bats.org.uk/

Related Species

• Bats