Nathusius' pipistrelle
Pipistrellus nathusii
Benoît Segerer · Finistère
Key facts in one look
- Diet
- Insectivore: midges, mosquitoes, blackflies
- Status in Georgia
- Native; rare records
- Size
- Body 4.6–5.5 cm, weight 6–16 g
- Habitat
- Riverside and mixed forest, water
- Family
- Vespertilionidae
- Conservation
- LC / LC
Nathusius' pipistrelle (Pipistrellus nathusii) is a long-distance migrant among Europe's bats: in the northeast of its range it covers up to 1900 km on seasonal flights. It is slightly larger than the common pipistrelle, weighs 6–16 g and has long, reddish-brown fur on the back. In Georgia it is known from few records: most of its 17 records come from old literature and museums. It has been found near Akhalkalaki, Kutaisi, Batumi, in Tbilisi and near Sokhumi. It looks very much like the common pipistrelle, so if you find a pipistrelle, do not touch it: the species is identified by a specialist.
Identification
Nathusius' pipistrelle: how to identify it
A small bat, slightly larger and broader-winged than the common and soprano pipistrelles. The back is reddish brown, with long, often shaggy fur. The face, ears and wing membranes are dark.
Size: body 4.6–5.5 cm, forearm 32–38 mm, wingspan 22.8–25 cm, weight 6–16 g. The common pipistrelle has a forearm of 30–35 mm and weighs 3–8 g. The measurements partly overlap, so size alone will not name the species.
The fifth finger of the wing is usually longer than 43 mm, while other pipistrelles have it shorter. The back fur is longer than in other pipistrelles and less evenly coloured. These features show only when the bat is in the hand, and that is work for specialists.
The echolocation call is loudest at about 38 kHz, lower than the common pipistrelle (45 kHz) and the soprano pipistrelle (55 kHz). Kuhl's pipistrelle has a similar call of about 40 kHz. So even with a detector these two can be hard to tell apart.
Colour
The back is medium to dark reddish brown, often with paler fur tips. The belly is pale brown, sometimes with frosted tips. The face, ears, wings and tail membrane are dark.
Swatches are illustrative. Do not identify a species by colour alone.
Nathusius' pipistrelle is a bat of riverside and mixed forests, often near water. It hunts over rivers, lakes, wetlands and along woodland edges. In summer it roosts in tree holes, buildings and bat boxes. It winters in rock crevices and cave entrances. Georgia has only 17 records. The oldest come from Akhalkalaki (1895) and Kutaisi (1921). Older literature mentions Tbilisi, Batumi, Chakvistavi, Tkibuli, Gelati, Tskhinvali and the Liakhvi reserve. In 2000–2016 it was recorded several times in Abkhazia, near Sokhumi, Bombora and in the Gumista valley, sometimes in January and February too. The latest records come from Nadarbazevi lake (2020) and Dedalauri (2021).
Nathusius' pipistrelle feeds on small to medium-sized flying insects, above all non-biting midges. It also takes mosquitoes, blackflies and caddisflies. It emerges early, at dusk. It hunts in straight lines with fast, deep wingbeats, 3–15 m above the ground.
Nathusius' pipistrelle is a migrant. In autumn, in late August and early September, bats from the northeast of the range fly southwest, sometimes up to 1900 km. On the way they follow coastlines and river valleys, and they return in spring. Mating runs from July to early September. A male gathers a group of females in his territory and attracts them with social calls. Part of these calls, at 20–30 kHz, can be heard by some people, especially children. In spring females gather in maternity colonies of up to 350 bats. In late May or June they often have two young. It lives up to 5–7 years.
Globally Nathusius' pipistrelle is Least Concern (LC, 2016), and its population trend is unknown. In Georgia's 2021 national assessment it is also Least Concern (LC), and its population is considered stable. It is threatened by the felling of trees with holes, toxic timber treatment in buildings, water pollution that reduces its insect prey, and the loss of woodland edges where it hunts. It breeds successfully in bat boxes.
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Yes, but it is rarely seen. The country's bat data hold only 17 records, 15 of them from old literature and museums. It has been found near Akhalkalaki, Kutaisi, Batumi, in Tbilisi, near Sokhumi and in the Gumista valley. The latest records come from Nadarbazevi lake (2020) and Dedalauri (2021).
Yes. In the northeast of its range it covers up to 1900 km on seasonal flights. In autumn it flies southwest along coastlines and river valleys and returns in spring. For such a tiny animal this is a very long way.
With difficulty. Nathusius' pipistrelle is slightly larger, weighs 6–16 g, has long reddish fur on the back, and its fifth finger is usually longer than 43 mm. Its echolocation call is at about 38 kHz, the common pipistrelle's at 45 kHz. This is checked with a bat detector or by measuring in the hand, which is work for specialists.
It does not attack you, but do not touch it with bare hands. A bat bite can be so small that you may not notice it, and direct contact with a bat is treated as a serious rabies risk. 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.
Small to medium-sized flying insects, above all non-biting midges, and also mosquitoes, blackflies and caddisflies. It hunts early at dusk, near water and along woodland edges. It flies in straight lines, 3–15 m above the ground.
It is not threatened. Globally it is Least Concern (LC, 2016), and Georgia's 2021 national assessment also lists it as Least Concern (LC). It is threatened by the felling of trees with holes and by toxic timber treatment. Old trees with holes are its roosts, so keeping them matters a great deal.
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.
