Pipistrelle bat

By Charlotte Owen

WildCall Officer

Bats are brilliant.  They are the only mammals on the planet capable of powered flight, and they can navigate through the darkest night by the power of echolocation.  Across the globe they are vital pollinators, valuable pest-controllers and even effective tree-planters.  There are 1,300 different species worldwide and they can be found almost everywhere but the frozen north and south poles.

Here in the UK there are 18 different species of bat, and all of them have been recorded in Sussex.  Sadly, many of our bat species are rare and the rarest of all is the greater mouse-eared bat.  Sussex is home to a single individual, who faithfully roosts in the same secret location every winter, and is almost certainly the last of his kind left in Britain.  He is also our largest resident bat species, with a wingspan of 45 cm – about the same as a starling.  At the other end of the spectrum is our commonest species, the pipistrelle bat, which is small enough to fit inside a matchbox.

Pipistrelles can be seen in gardens, parks and urban greenspaces where they are sometimes mistaken for small birds flitting about at dusk.  They first leave their roosts about twenty minutes after sunset, flying fast, low, and seemingly erratically as they zig-zag after their insect prey.  Despite their diminutive size, pipistrelles have a healthy appetite and will each devour 3,000 flies, midges and mosquitoes in a single night, catching and eating their food on the wing.  If you were to listen in with a bat detector, you’d discover that some pipistrelles emit their rapid-fire echolocation calls at a much higher frequency, and we now know there are two distinct species: the Common Pipistrelle and the Soprano Pipistrelle.  They are joined by a much rarer (or possibly just under-recorded) third species, Nathusius' Pipistrelle.  There's much we still don't know about this mysterious, migratory Pipistrelle but it is recorded in good numbers at Rye Harbour Nature Reserve, and ringing data has revealed that one bat travelled there all the way from Latvia (flying an impressive 1,453km).  

Like all of our bat species, Pipistrelles rely on flying insects but as the bounty of the summer months diminishes and autumn shifts towards winter, food is harder to come by and bats prepare to hibernate.  Pipistrelles are small enough to tuck themselves into tiny cracks and crevices in trees or buildings, where they often go completely unnoticed until they emerge in spring - the secret stars of the night sky.