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Bat Surveys Explained

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The first time that many of our clients learn of bats and their status as a protected species is when they are made aware of the need for a bat survey by the local planning authority. Whether it’s to convert a loft, re-roof a property, or to demolish a building, a bat survey is often a necessary part of the planning process.

We have been asked before if this is just a formality. However, a bat survey is more than just a box ticking exercise. Bats are a protected species under the Wildlife and Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2010, and causing harm to a bat is a criminal offence. What is more, damaging a breeding or resting place of a bat, even if no bats are present at the time, is also a criminal offence. However, don’t panic! Our experienced consultants are able to determine whether roosting bats are present in your property, and in the event that they are, we are able to guide you through every stage of the process.

The Bat Scoping Survey

The first stage of the process to determine if a building has bat roost potential is a Bat Scoping Survey. This is carried out during the day, at any time of the year. One of our consultants will visit your property and undergo a search for bats and their habitats. This involves an interior and exterior inspection of the property, looking for direct evidence of bats, such as droppings and feeding remains, and for suitable habitats for bats, such as missing roof tiles, gaps in the brickwork and potential access points into a loft. This is supplemented by a desk based study, whereby we check existing records of bats near the development, and we appraise the surrounding area for its potential to support bat roosts.

Often a Bat Scoping Survey is all that is required to attain planning permission. If we determine that no bats are present, and the building has negligible potential to support bat roosts, there will be no further recommendations in regard to bats. If however, the building is determined to have potential for bat roosts, further dusk/dawn surveys are usually recommended.

Dusk/Dawn Surveys

In accordance with the Bat Conservation Trust’s guidelines, the survey effort required is dependent on the building’s bat roost potential:

  • If the building has low roost potential, a further dusk emergence and/or pre-dawn re-entry survey is usually required.
  • If the building has moderate roost potential, two further dusk emergence and/or pre-dawn surveys are usually required.
  • If the building has high roost potential, three further dusk emergence and/or dawn re-entry surveys are usually required.

Dusk/dawn surveys are carried out through the months between May and September, when bats are active. Our consultants will visit the property at dusk and/or dawn, and monitor any potential roost features with heterodyne and frequency division bat detectors to determine if any bats are entering or leaving the building. If no bats are found, we can conclude that there are no roosting bats present, satisfying the relevant planning conditions. If bats are found, and are deemed to be affected by the proposed development, a European Protected Species License and mitigation will usually be required.

European Protected Species Licenses

In order to apply for a European Protected Species License, we will need to assess the nature of the bat roost. Whether it is a large maternity roost or a solitary bat present will have an effect on the level of mitigation required. This is usually done through the prior dusk/dawn surveys. We will then apply for the European protected Species License, recommending mitigation as appropriate. Typical mitigation procedures include:

  • Incorporating purpose built roosts into a development (such as bat boxes and/or bat barns).
  • Recommending that a watching brief by a licensed bat worker takes place.
  • Retaining existing roosts in refurbished buildings.

Further Information

For further information, we recommend visiting the Bat Conservation Trust’s website, where all their recommendations are available online. Otherwise, please call our office for an informal chat about your requirements.

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