Planes, boats and bats: the ‘crazy idea’ that has sky-high potential for wildlife research

Brown long-eared bat - found in Suffolk (Image: Archant)

This trend was much in evidence at the recent Suffolk Naturalist Society’s (SNS) conference, where the audience heard from Nicky Rowbottom from the Suffolk Otter Group which is using trail cameras to capture visual evidence of the mustelids on the Suffolk coast.

Earlier in the day, Suffolk Wildlife Trust’s hedgehog officer for Ipswich, Ali North, explained how she is employing radio tracking to monitor and retrieve data from tagged animals.

The latest gadgets to capture the imagination of naturalists are drones or unmanned aerial vehicles (UAVs), as they are sometimes called. Drones are best described as computerised aircraft or boats that can be guided remotely or navigate themselves autonomously to reach inaccessible areas - they are already used in numerous conservation projects around the world: from tracking turtles over large areas to monitoring the extent of deforestation in tropical forests and locating rhino poachers in South Africa.

Most recently, drone imagery has enabled scientists to discover previously unknown populations of Adélie penguins – incredibly numbering over 1million - in the Danger Islands off the northern tip of the Antarctic Peninsula.

And it was the use of drones, this time as a tool for bat research and conservation, which was the subject of an engaging talk given by Dr Tom August at last month’s SNS event.

Born in Suffolk, Tom is a researcher at the Biological Records Centre based at Wallingford near Oxford. He has a PhD in bat ecology and over the past three years he and a friend from university have spent some of their spare time experimenting with how best to attach a bat detector to a drone in order to record the high frequency ultrasonic calls, which the flying mammals use for echolocation.

“It’s really a story of what happens when a couple of guys get together and have a crazy idea and just go with it,” explained Tom, introducing his presentation, which turned out to be a tale of perseverance in the field of wildlife research.

The duo’s initial experiments involved the use of a quadcopter drone but early forays showed that the noise created by its four wings was interfering with the detector’s ultrasound recordings. They worked out that the recorder should be three metres from the drone to avoid this interference, so in an early trial they tied a water bottle (so as not to risk the detector) to a length of string and suspended it from the drone. They soon found out this set-up created a pendulum effect that destabilised the drone and sent it crashing to the ground.

Next up were trials with a drone plane which, by turning the engine off, could glide and create less disturbance to the detector. However, without the software to command the vehicle in glide-mode over longer distances, this solution proved impractical.

A breakthrough came in early 2017 when they were contacted by a company called Peer Sonic who gifted them a lightweight bat detector, which it had developed. This smaller device could be suspended successfully from the quadcopter which led to pipistrelle bats being recorded, believed to be the first bat recordings from a drone.

A boat drone was also employed and, after a few crashes, pipistrelle and serotine bats were recorded on the Thames.

The pair are now using a new generation of drones that fly for longer and make less noise and have had several successful outings.

The concept proved, Tom says the technology has the potential to improve bat surveying at height and to enable surveys to be carried out across large areas much quicker and more accurately.

He says he now he needs to test his drones on a bigger project - maybe a major wind turbine installation - to see how his approach compares to traditional surveys.

Tom has also established a project with a masters student at the University of East Anglia to look further into whether the presence of drones affects bat behaviour.