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At a glance
| Size: | Length 60–80 mm; wingspan 320–400 mm; weight 18–40 g. |
|---|---|
| IUCN (GB): | Least Concern. |
| Call peak: | ~20-25 kHz (low enough to be audible as “chip-chop” sounds to many people). |
| Active: | Emerges typically just before or right at sunset, often earlier than most other bat species |
Flies high and fast in straight lines, often above treetops, open fields, parkland, and over water.
Identification
The noctule is noticeably bigger than pipistrelles, flying high and fast, often straight-line flight at dusk. Calls are deeper than most bats and sometimes audible to the unaided ear. In silhouette they resemble small swifts.
Life history
- Breeding: Maternity colonies of 20–150 females form in tree cavities during spring/summer. Single pup born late June–July; Flying at ~3–4 weeks
- Mating: Autumn “swarming” at roost entrances and during flight.
- Lifespan: The average is typically 5–8 years, although some individuals can live up to 12–15 years in the wild.
Roosting
Prefers tree cavities (old woodpecker holes, rot hollows), also bat boxes and occasionally buildings. Roosts are often switched frequently. Colonies require mature woodland landscapes with abundant trees.
Hibernation
November–March, in hollow trees, crevices, occasionally in buildings or underground sites. Often hibernates singly or in small groups.
Feeding & foraging
Feeds on large flying insects such as cockchafers, beetles, moths and caddisflies. Strong fast flight allows it to hunt high over tree canopies, along woodland edges, and above open fields or water.
Echolocation
Calls peak around 20–25 kHz, with long-duration signals. Many people under 40 can just hear them unaided as faint “chip-chop” sounds on summer evenings.
Population & conservation
- Historically reduced by loss of old trees and woodland, and insect declines.
- UK monitoring suggests the noctule population is stable or slightly increasing since the late 1990s.
- Conservation relies on preserving old trees, maintaining foraging habitats, and minimising disturbance of roosts.
In Sussex
- Recorded across the county but far less numerous than pipistrelles.
- Best detected on bat detectors in mature woodland, parkland, and over rivers or lakes.
- Frequently seen on summer evenings flying high and fast over open areas.
How to help
- Protect mature trees with cavities; retain standing dead wood where safe.
- Provide large bat boxes in suitable woodland.
- Support insect-friendly land management—wildflower areas, reduced pesticide use.