Common Pipistrelle 

I spend way too much time in graveyards (especially considering that I’m going to spend an awful lot of time in one in the future). But they are great places to look for Pipistrelle bats. At this time of year, adult Pipistrelles are emerging from their winter hibernation and taking flight. Above Sussex, the night sky is a battlefield of deafening cries as Pipistrelles swoop and swirl, plummet and pounce at their insect prey.

The acrobatic anarchy overhead goes unnoticed by us humans. Our hearing is limited, and when it comes to night vision we’re as blind as - well, something with really bad eyesight...in fact anything but a bat. Bats have excellent vision. But it certainly isn’t their best sense.

Echolocation is one of the animal world’s most incredible superpowers. As a Pipistrelle shouts, the shout hits something and bounces back. This echo is instantly analysed in an amazing brain and tells the bat how far away the object is and whether it’s a mosquito, a moth or a mansion. To get the maximum information from their echo, Pipistrelles yell at high frequencies (45 kHz; we can only hear up to 20 kHz). And these shouts are loud; pneumatic drill or jet fighter loud. Up to 110 decibels in some species. A bat would deafen itself if it heard its own shout. So Pipistrelles have to disengage their ears, then shout, then turn their hearing back on, listen for the echo, analyse, then start all over again. All at the rate of 10-15 times a second. This gives bats an amazing, multi-layered awareness of their surroundings. But it’s tricky (and impolite) to shout when you’re eating, so once a moth is in the mouth the bat has to chew-shout- listen-chew-shout-listen to avoid a collision.

There are 17 different species of bat in Sussex. Our smallest – the Common Pipistrelle – is also the one you’re most likely to see around your gardens. Back in the 80s there were just four TV channels, two types of videocassette and one species of Pipistrelle in Britain. But in the 90s, scientists discovered that some Pipistrelles were echolocating at higher frequencies (55 kHz); a Montserrat Caballé to the Common Pipistrelle’s Freddie Mercury. These are the Soprano Pipistrelles. There’s now a third: Nathusius' Pipistrelle. By affixing lightweight metal rings to this species’ wings, researchers have discovered that these bats are migrating to Sussex from as far away as Latvia. An amazing journey for an amazing animal.