Drones and bat surveys

Throughout 2016 Practecology undertook a number of building surveys to determine the value of drones in facilitating the design of bat activity surveys.

Drone technology and application

Many commercial industries make use of drones: energy suppliers assessing their network infrastructure; oil and gas producers undertaking maintenance checks both onshore and offshore, and; film and television production companies using them as a substitute for helicopters, gantries and dollies. The GIS community have also relied heavily on drones for spatial mapping and it is possible to use computerised 3-D models to view construction sites throughout their development or determine habitat type without having to walk for miles over rough terrain. The list is endless and with the further expansion of drone technology the sky is perhaps not the limit it once was perceived to be.

Applying drones to ecology surveys

Using drones for wildlife surveys is not new. Over the past number of years research institutes and universities have tested the value of drones fitted out with a range of cameras on a number of target species and met with some exceptional results. However, as prices drop and technology is more accessible, the use of drones in ecology should not be considered to be the property of large institutes. Although competing with these organisations can be discouraging at the start, not least choosing a suitable drone can be equally as confusing, there is scope for smaller ecological consultancies to embrace this technology and apply it to our discipline.

Following its success in gaining a Permit for Aerial Works from the CAA, Practecology undertook a number of drone surveys to see if they could be used to facilitate a range of ecology surveys. All flights were carried out in accordance with Practecology's flight manual.

Bat Surveys

Using drones to carry out daytime inspections of multi-storey buildings is perhaps one of the most useful applications for small consultancies. It allows all parts of a building to be surveyed in a relatively short time, enables access to obscured or inaccessible sections of roof or masonry and gives a full understanding of a buildings layout which can inform resourcing for further activity surveys. By using a 4K high definition camera likely points of bat access can be identified, such as missing slates, gaps under flashing, or damaged sections of roof. Captured images may also provide a useful addition to protected species license applications and may be invaluable in designing a suitable mitigation strategy.

Building inspections for bats

Building inspections for bats

Aerial image to aid survey planning

Aerial image to aid survey planning

Assessing obscure roof sections

Assessing obscure roof sections

Identifying missing slate on multi-storey builing

Identifying missing slate on multi-storey builing

Pros and Cons

Certainly drones have their uses in planning bat surveys, particularly where developments are comprised of multi-storey buildings or large complexes. Identifying areas where bats may gain access will improve survey efficiency, reduce costs and remove the uncertainty as to the origin of bats which may be recorded during dusk or dawn surveys. Often any uncertainty is addressed through the drafting and submission of protected species licences which in turn require a suitable mitigation strategy to be implemented before works. By confirming the absence of potential points of entry then it should be possible for surveyors to have more confidence in separating roosting bats from those foraging around the building.

Although there are advantages there are still hurdles to overcome. Pilot training, drone purchase, insurance and ancillary equipment is not cheap. Flights are also weather dependent and problems associated with wind sheer and downdrafts near buildings requires the pilot to have some experience, not least to know when to abandon flying. Camera orientation and mobility prevents the drone from looking upwards and identifying gaps under guttering or in soffits, although this is also a problem faced by traditional inspections.

Future advances in technology may overcome some of these limitations but it is considered that the benefits are considerable. Of course there is also scope to attach bat detectors to drones and carry out surveys at greater heights or use them to deploy detectors on top of buildings where they may be out of site from members of the public.

It is clear that further testing is required!

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