Common Pipistrelle

Common pipistrelle on rock (© Rosie Corner / Bat Conservation Trust)

A widespread species of bat, the common pipistrelle (Pipistrellus pygmaeus) is distributed throughout UK. It is a generalist species and can be found in a wide variety of habitats, including urban and suburban environments such as parks, gardens and around street lamps.

The common pipistrelle is a small, brown bat with triangular ears. It has a dark face, (almost black) with black ears. It has a two toned fur; black rooted and brown outer. Like the Soprano Pipistrelle, the common pipistrelle weight is normally around 3 – 8g (the weight of a two pence coin). Maternity colonies are formed from May and young are born around June/July (1 pup to each female). The neonates (newborns) can weigh 3.3g in 10 days, 4.1 g in 20 days, are independent at 4 weeks and foraging by themselves in 6 weeks. By the end of their first autumn young female bats will have reached sexual maturity.

Calls of the common pipistrelle can be picked up on a heterodyne detector between 45kHz – 70kHz. The calls sounds like a series of clicks and wet slaps and at the peak frequency of 45kHz, the deepest, clearest calls can be heard. In general most calls made by bats are normally above our hearing range. However, young children and adults with exceptionally good hearing can hear the ‘chonk’ sounding social calls made by pipistrelles (around 22kHz), without the aid of a detector.

On a sonogram, the shape of a pipistrelle call is a distinctive ‘hook’ or ‘hockey stick’.A common pipistrelle recorded on an Echo Meter touch
outside All Saints Church, Besthorpe on the 4th July 2015 

Emergence time for a common pipistrelle is around 20 minutes after sunset. It flies and forages about 2 – 10m above ground, ducking and diving and catching its prey on the wing. It eats mainly flies (Diptera) and occasionally midges and mosquitos. Its distinctive jerky, fast and erratic flight is easily recognised.  In fact it is the bat you are most likely to see when out in your garden at dusk.

Common pipistrelles are a synanthropic species (closely associated with humans). Both their summer and winter roosts are located on the outside of buildings under wall claddings, cavity walls, eaves and roof coverings. Occasionally they will also roost in trees and bat boxes. Females are less loyal to their roost compared to other species of bats. They have been known to move their maternity colonies every 12 days. Though populations are stabilising, due to their dependence on our buildings, pipistrelles are still very vulnerable to changes such a building renovations and timber treatments.