The common pipistrelle weighs just 3–8 grams — roughly equivalent to a 2p coin. Despite its tiny size, it can eat up to 3,000 small insects per night. It is found throughout the UK and Ireland, and is the bat species most commonly encountered by the public, as it readily roosts in buildings and forages along linear features such as hedgerows, woodland edges, and rivers.
Pipistrelles use echolocation calls at 45 kHz (versus the soprano pipistrelle at 55 kHz — a species separated from common pipistrelle only in the 1990s). They hibernate from October to March/April in cool, stable roosts.
In the UK, all bat species are protected under the Wildlife & Countryside Act 1981 and the Conservation of Habitats and Species Regulations 2017. It is illegal to:
Building works affecting bat roosts require a bat survey and, if bats are present, a licence from Natural England, Natural Resources Wales, or NatureScot.
The most significant welfare threat to pipistrelles is disturbance and loss of roost sites. Bats return to the same roosts year after year; losing a maternity roost — where females gather in spring to give birth and rear pups — can devastate a local colony. Common causes:
As aerial insectivores, pipistrelles are directly affected by declines in flying insect populations. Agricultural intensification, pesticide use, and light pollution all reduce the insect prey available. Studies monitoring pipistrelle populations have correlated their abundance with insect diversity and abundance at foraging sites.
Artificial light at night significantly affects pipistrelles. While common pipistrelles are relatively light-tolerant (and may even exploit lit areas to catch insects attracted to lights), artificial lighting at roost entrances can delay emergence, particularly in maternity roosts. This reduces foraging time and can impair pup survival.
Domestic cats are a significant cause of bat mortality. Bats injured by cats (even without obvious wounds) almost always require rehabilitation due to Pasteurella bacteria in cat saliva causing systemic infection. Any bat found after a cat encounter should be taken to a bat carer.
Pipistrelles foraging along linear features cross roads and are vulnerable to vehicle strikes. Road casualties are regularly recorded. Low-level flight near hedgerows and woodland edges brings them into the traffic zone.
Bat boxes (timber or woodcrete) provide supplementary roost sites, particularly valuable where natural roosts are limited. Pipistrelles prefer narrow-gap boxes (14–17mm entrance). Position in groups of 3+ on south/southwest-facing aspects at 3–5 m height. Check and clean boxes annually (requires a bat licence).
Use bat-sensitive lighting where possible: amber LED rather than white, motion-activated, directed downward, and away from roost entrances, hedgerows, and water bodies.
Found a bat on the ground during the day, or an injured bat? Do not handle without gloves (bats can carry European Bat Lyssavirus, a rabies-related virus). Contact the Bat Conservation Trust helpline (0345 1300 228) for advice on finding a bat carer. Never attempt to feed or water a bat without professional guidance.