Bats at Bath City Farm

Bats are not the first animal to spring to mind when someone mentions Bath City Farm. But as the farm's collection of goats, pigs, cows, sheep, chickens and ducks settle down for the night, another creature uses the open spaces, hedgerows and trees as it's hunting ground...

The type of bat you are most likely to see flying over the farm is the Common Pipistrelle. It flies with a twisting, fluttering movement and often follows a regular route to the usual place where it feeds on insects. The Pipistrelle has a very small body, growing up to 4.5 centimeters in length. It has dark fur, a slightly paler belly and short round ears.

Left: a Common Pipistrelle Pipistrellis pipistrellis takes off in flight
Right: the beeches at Bath City Farm are a night-time habitat for bats

The Pipistrelle bat typically roosts in trees holes, bird boxes, under roof tiles and in crevices. Bats hibernate in the winter. If you find a bat roosting you should leave it undisturbed. It is inadvisable to handle bats as a small number of them appear to have contracted rabies.

Bats use a form of sonar to find their way around and catch flying insects. This means they shout high pitched sounds that bounce off other objects. By listening to the sounds bouncing back, bats can discover the size, location and possible movement of an object. These sounds are too high pitched for humans to hear, but a bat detector turns them into audible sounds that we can hear.

The video is of a bat detector picking up Pipistrelles during a Bat Walk at Bath City Farm in August. About 9pm is a good time to start looking for bats in that month. We saw them flying around the big avenue of beech trees in one of the fields.

When you play the video you will hear series of well defined clicks that get faster and finish with a sort of buzz. Our guide explained that as a bat gets closer to an insect, the sounds it makes take less time to bounce back. So the bat is able to emit the sounds more rapidly as it homes in on the insect.

Photo

The photo of the Common Pipistrelle is from the Shetland Biological Records Centre.