Many species choose to roost in buildings and due to their nocturnal lifestyle, you may not even be aware of their presence in your house. In addition to housing, bats will make use of a wide variety of built structure including bridges, cellars and tunnels, as well as trees, caves, mines and bat boxes.
It is thought that almost all species in the UK have experienced declines in range and population size over the past few decades, with one of the main causes thought to be development. As more of the landscape is used for housing, bat roosts are being destroyed, feeding habitat removed and vital commuting routes severed. Therefore, it is important to ensure that development is undertaken in a sustainable manner for bats.
Bats and the Law:
All bat species and their roosts in the UK are protected under European and UK law. The main piece of legislation protecting UK bats is The Conservation of Habitats and Species Regulations 2010 (as amended) (better known as the Habitats Regulations). In addition to this, bats and their roosts are also protected in England and Wales under the Wildlife and Countryside Act 1981 (as amended) and The Countryside and Rights of Way Act 2000 (as amended). Under these pieces of legislation, it is an offense to:
- Deliberately capture, injure or kill a bat.
- Deliberately disturb a bat in a way that would affect its ability to survive, breed or rear young (or hibernate or migrate in England, Wales and Northern Ireland) or (significantly in England, Wales and Scotland) affect the local distribution or abundance of the species.
- Damage or destroy a roost (this is an ‘absolute’ offence).
- Possess, control, transport, sell, exchange or offer for sale/exchange any live or dead bat or any part of a bat.
- Intentionally or recklessly disturb a bat at a roost.
- Intentionally or recklessly obstruct access to a roost.
Before planning any development, careful consideration should be given to its potential impact on bats. If there are any built structures or trees on site, do they contain roosts? Is the site used for foraging? Do you have an important linear feature such as a hedgerow that is used by commuting bats?
The first bat survey you should commission at a site is a scoping or bat roost potential survey. This will involve a consultant visiting the site and looking for signs of bat activity and assessing the site potential for bats. When looking for roosts in buildings, surveyors will look for features such as gaps in brickwork, missing tiles, staining around holes, droppings, feeding remains and/or carcasses.
This initial survey should usually include a desktop study, which would involve contacting local groups or record centres in order to obtain previous records of bats in the area. This can indicate whether the area is good for bats and what species are most likely to be encountered.
If this survey indicates a site is likely to support bats, recommendations will be made to conduct further surveys.
Emergence / Re-entry Surveys:
If the site has the potential to support bat roosts an emergence/re-entry survey will be required in order to determine presence/absence of bat roosts. This will involve an appropriate number of consultants being positioned around a site, equipped with bat detectors, looking for bats emerging from or entering a roost site. Best practice guidelines for these surveys recommend that 2-3 surveys are conducted across the breeding season (May - September), starting approximately 30 mins before sunset and up to 2 hours after for emergence surveys, and 2 hours before and up to 30 mins after sunrise for re-entry surveys.
If bat roosts are found during these surveys, recommendations for how to proceed will be provided. This may mean timing works outside of the bat breeding season and applying for a Natural England licence.
If the development is likely to affect foraging or commuting bats, an activity survey will be required to see how bats are using the site. This is especially important when considering the erection of wind turbines.
This survey involves one or more consultants, equipped with bat detectors and recording devices, visiting the site around 2 – 3 times within the breeding season, around 30 minutes before sunset and up to 2 hours after. The surveyors will then document all bat activity encountered during the survey, noting species, frequency, location and pattern of behaviour.
A report will then be produced recommending what features should be retained due to their importance for bats and what mitigation is required to compensate for the development.
Survey Time Line: