Noctule
Nyctalus noctula
Jukka Jantunen · 89415 Lauingen
Key facts in one look
- Size
- 18–40 g, wingspan 32–40 cm
- Diet
- Insectivore: beetles, moths, small flying insects
- Status in Georgia
- Native, widespread
- Habitat
- Broadleaf forest, parks, towns
- Family
- Vespertilionidae
- Conservation
- LC / LC
The noctule (Nyctalus noctula) is a large, fast bat: it weighs 18–40 g, has a wingspan of 32–40 cm and flies at 50 km/h. It comes out earlier than many other bats, while it is still dusk, and hunts high over the forest. In Georgia it is widespread: it has been found in Tbilisi, Mtskheta, Kutaisi, Batumi, Zugdidi, Borjomi and Lagodekhi. On hot summer days a colony gives loud, metallic chattering from its tree hollow. The giant noctule and the lesser noctule look very much like it, so they are told apart reliably only by size. Do not touch a bat with bare hands.
Identification
Noctule: how to identify it
A large bat with narrow, long, pointed wings and sleek chocolate-brown to reddish-brown fur. The ears are broad and brown, and the snout is pointed. It flies high, straight and fast, and chases insects with steep dives. The giant and lesser noctules look similar.
Size is the main feature. The body is 6–8.2 cm long, the forearm 47–52 mm, the wingspan 32–40 cm and the weight 18–40 g. The lesser noctule is smaller (forearm 38–47 mm, 12–20 g), and the giant noctule much larger (forearm 62–68 mm, 41–76 g). Do not catch a bat to measure it: that is a job for specialists.
The fur is short and sleek, and each hair is one colour along its whole length. The lesser noctule's fur is darker at the base, which is a good difference between them. Adults are chocolate brown, while young bats and some females are duller.
The ears are broad and brown, and the small inner flap of the ear, the tragus, is mushroom-shaped. Other noctules have the same tragus, so this feature only tells you the genus.
Its echolocation calls lie at 20–45 kHz, loudest at about 25 kHz. Some adults and children can hear them. On a bat detector, a hunting noctule gives a characteristic 'chip-chop', with occasional clicks.
Colour
Adults are sleek chocolate brown; young bats and some females are a duller chocolate brown. After the summer moult the fur is dark brown, and before winter it turns reddish-brown. The belly is slightly paler than the back.
Swatches are illustrative. Do not identify a species by colour alone.
The noctule is mainly a forest bat, but it has adapted well to towns. It prefers broadleaf forests with old trees, parks and gardens, though it also lives on farmland. It spends the day mostly in tree hollows and old woodpecker holes, sometimes in buildings, attics and bat boxes. It reaches 2,000 m. At night it may fly more than 10 km from its roost to hunt. In Georgia it is widespread, from the coast to the Iori Plateau. It has been found in Tbilisi, Mtskheta, Kutaisi, Batumi, Zugdidi, at Anaklia and in Kolkheti National Park, in Borjomi and Tkibuli, in the oak forest of Ajameti Managed Reserve, in Gardabani Managed Reserve and the riverside forest at Rustavi, in Lagodekhi and in Abkhazia. Records span 1894–2020.
The noctule eats insects and changes its food with the season. In spring it catches smaller insects: midges, mayflies and winged ants. Later it switches to beetles, mainly cockchafers and dung beetles, and to moths. It catches most prey in flight and eats it on the wing, but sometimes takes it from the ground. In towns it hunts around street lamps, where moths gather. It hunts for up to two hours at dusk and for about half an hour at dawn.
The noctule is a migratory species: its summer and winter roosts are often hundreds of kilometres apart. It usually travels up to 750 km, and the record is 2,347 km. Noctules from the eastern Black Earth region of Russia fly to the Caucasus and Crimea for the winter. It leaves in late August and September, covering 30–40 km a day and feeding on the way. It usually starts hibernating in November, in tree hollows, rock crevices or buildings, sometimes in groups of up to 1,000 animals. It can go almost four months without food and tolerates −7 °C. Mating takes place in late summer and autumn. A male takes over a mating roost in a tree hollow, keeps other males away, calls loudly and gives off a strong smell. This way he attracts 4–5, sometimes up to 20 females. The female stores the sperm through the winter, and fertilisation happens only in spring. The young are born in late June or July, usually one, sometimes twins. For 3–4 weeks they live on milk alone, and at 6 weeks they hunt on their own.
Globally the noctule is rated Least Concern (LC, 2016). In Georgia the 2021 national assessment also rates it Least Concern (LC), with a stable population. In the European Union it is protected under the Habitats Directive, and it is listed under the Bern Convention and the Agreement on the Conservation of Populations of European Bats (EUROBATS). It was chosen as 'Bat of the Year' in 2016 and 2017. Its main threat is intensive farming, which shrinks insect-rich feeding grounds such as pasture and woodland edges. The felling of hollow trees is a threat too. In Britain this has made it scarce in some areas.
Related guides
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Yes, and it is widespread. Data from 1835–2022 hold 89 records. It has been found in Tbilisi, Mtskheta, Kutaisi, Batumi, Zugdidi, Borjomi, Lagodekhi, the riverside forests of Gardabani and Rustavi, and in Abkhazia. You are most likely to notice it at dusk, flying high and fast over the trees.
By size. The noctule weighs 18–40 g and has a forearm of 47–52 mm. The lesser noctule is smaller, 12–20 g, and its fur is darker at the base. The giant noctule is much larger, 41–76 g, with a forearm of 62–68 mm. All three have narrow wings and a mushroom-shaped tragus, so specialists tell them apart reliably.
It does not attack you, but do not touch it with bare hands. A bat bite can be tiny and easy to miss. Rabies cannot be ruled out by appearance, although most bats seen are not rabid. After a bite or scratch, wash the spot with soap and water for at least 15 minutes and see a doctor; in an emergency, call 112.
Stay calm and take children and pets out of the room. Close the doors to other rooms, open an outside window or door wide and switch off unnecessary lights. Then step back and give it time: a bat usually finds the way out by itself. Do not try to catch a flying bat.
Yes, it is a migratory bat. Its summer and winter roosts are often hundreds of kilometres apart, usually up to 750 km, and the record is 2,347 km. Noctules from the eastern Black Earth region of Russia fly to the Caucasus and Crimea for the winter. It is mainly the females that migrate, while males stay along their route.
References
What this profile is based on
Species profiles are compiled from peer-reviewed literature and established biodiversity databases, and are reviewed as new taxonomic and conservation data become available.
Prepared by the Reptiles.ge editorial team from the sources listed here.
