Preparing for the Bat walk – Photo by Ian Fraser

At 7:00 pm on Monday 15th September 6 volunteers from the Woodland Group met on the grassed area in Birch Drive. The weather had been terrible for most of the day with heavy rain and wind, just the type of weather that bats don’t like. However, luck was on our side and after having 20mm of rainfall during the day we had a break in the weather just as 10 adults and 4 children came from the surrounding area and arrived for the bat walk.

After a short talk by Gareth on British Bats likely to be seen during the walk, 20 people set off in the hope that the bats would come out to play. Several members had brought along Bat detectors to help with the identification of any bats that we were lucky enough to see. The group entered the woodland as much to avoid the wind and rain that was still threatening to ruin the evening than in the hope of seeing any bats. After a few minutes in the woodland the high pitched sounds from the bat detectors could be heard. At the same time some people taking part started pointing into the air as the bat population in the woodlands started to circle the area warming up ready for a night of frantic feeding. Up until now the bats in the woodland have only been seen in ones or twos searching for insects to eat, but this evening saw them emerging from the tree sites and swarming ready to set off hunting.

As the night closed in it was more difficult to spot the bats flying around, however with the bat detectors we were able to identify which bats were flying above our heads. All the bat detectors being used during the walk convert ultrasonic sounds emitted by the bats into audible frequencies that humans can hear. The bats use these ultrasonic sounds,
or echolocation, which is biological sonar to locate their prey insects. These ultrasonic sounds can then be displayed as colour spectrograms or save the sounds as full-spectrum WAV files if you use a Full Spectrum/direct sampling bat detector. Some of the Bat Detectors allowed Keyhole Markup Language (KML) files to be downloaded and later used in a Graphical Information Systems (GIS) software to create map data of the location of the various bat species.

Bat Location Map – Click to view

The walk continued along the core path out to the side of the woodland where more bats were seen flying among the trees and along the paths. By 9:00 PM after an enjoyable evening observing the woodland bat population everyone made their way home.

Further reading: Bat Conservation trust https://www.bats.org.uk/