Common Pipistrelle

Pipistrellus pipistrellus

Description and identification

Common pipistrelles are one of the smallest bats found in the UK, and are the ones that you are most likely to see flying at dusk. A small brown bat, the common pipistrelle has short ears, and weighs only 4-8gms – about the same as a pound coin! The ‘common pip’ normally (but not always) has a black band across the face, leading to their nickname of ‘the bandits’. They are quite recognisable when in the air, with a characteristic jerky flight pattern as they hunt for insects.

The common pipistrelle, the most common species of bat in Europe, was only confirmed to actually be two species through molecular genetics50 after two distinctive echolocation frequencies were established51. The separation of these two bats through the application of mitochondrial sequence analyses was one of the first among European mammals52.

Status and distribution

The common pipistrelle is our most widespread bat species, present throughout Great Britain and Ireland. It is generally accepted that there were significant historical declines in pipistrelles (and other bat species) from at least the beginning of the 20th century53, if not earlier. There are now signs that the population is starting to increase again. The latest report from BCT shows that there has been an 82.1% increase in numbers since the baseline year of monitoring in 1999.

The common pipistrelle is the only species to have been recorded in all of the 36 hectads of Nottinghamshire.

Roosts

In summer, common pipistrelles are likely to be found roosting in building crevices – under roof coverings, in soffits and fascias, or under hanging tiles. Females will gather in groups of around 50 bats, sometimes in greater numbers but usually fewer than 200, to give birth to a single pup. Once the young are able to fly, the colony often breaks up and the animals roost in smaller numbers. They often return to the same maternity site year after year. Individual bats, especially males may also be found in low numbers in rock crevices or under tree bark54.

Little is known about where common pipistrelles hibernate in Nottinghamshire or anywhere else in the UK for that matter! They are known to hibernate in underground cellars, tunnels and caves and occasionally in cavity walls but are only ever found in low numbers. They need cool, stable and humid temperatures to remain torpid.

Food and foraging

The common pipistrelle eats a variety of different flies, as well as aquatic midges and mosquitos – in fact they have been recorded eating up to 3000 midges in a night! If you’re listening to a pipistrelle on a heterodyne bat detector then listen out for a sound like a raspberry, or a ‘zip’; this is the sound made when the bat homes in on its prey. As the bat gets closer to its prey, its calls also get closer together, producing what is called a ‘feeding buzz’.

The common pipistrelle is very much a generalist bat species and being adaptable it is found across the country in both urban, suburban and rural areas. It is often seen hunting for food in urban parks and gardens and around street lamps where flying insects have been attracted to the light.

© Nottinghamshire Bat Group. Not to be reproduced without written permission. Each dot represents either a roost, a grounded bat or a bat detector record where the call has been identified to a good level of certainty.