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With 41.24% of votes and likes (306 out of 742), the bent-winged bat (Miniopterus schreibersii) becomes the Bat of the Years 2026–2027 in Romania. Thanks to everyone for participating.

It is important to note that the protection of the 31 bat species that are not currently Bat of the Year remains just as important as before. Our efforts, those of CBRC, are always focused on all Romanian bat species.

The bent-winged bat is typically cave-dweller: all throughout the year it forms colonies exclusively in caves or other underground places, for example in mine galleries. Thus, both hibernation colonies (in winter) and maternity colonies (in summer) are formed underground. The species forms some of the largest bat colonies of Europe in Romanian caves, for example in Huda lui Papară Cave (with more than 34,000 individuals in hibernation), or Șura Mare Cave (with more than 25,000 individuals in hibernation), or in the Betfia Pothole (with more than 7,000 bats in the maternity colony). However, enormous colonies of tens of thousands of bats can also be found in France, Bulgaria, Croatia, and Spain.

While hibernation colonies usually consist only of individuals of this species, maternity colonies may include other species as well. Females of the bent-winged bat often share maternity colonies with greater mouse-eared bats (Myotis myotis), lesser mouse-eared bats (Myotis blythii), or horseshoe bats (Rhinolophus spp.).

The bent-winged bat is a medium-sized species compared to other Romanian bats, with almost uniformly colored fur, dark grey to blackish-brown. The species’ name comes from its very long and narrow wings, which allows individuals to have very fast and highly maneuverable flight. With its long and narrow wings, the bent-winged bat hunts insects inside deciduous forests, but the proximity to water surfaces is also important. Because colonies contain hundreds or thousands of individuals, bats must spread over large areas in search of insects. Therefore, the species may travel considerable distances every night, often 10–15 km from the roost, to find prey.

It prefers Lepidoptera, but also feeds on Neuroptera, Diptera, and Coleoptera. The ultrasounds emitted during flight have an average frequency around 55 kHz and should not be confused with the very similar calls of the soprano pipistrelle (Pipistrellus pygmaeus), which emits at roughly the same frequency.

The bent-winged bat migrates seasonally between summer and winter roosts over distances of 40–100 km. In a project implemented by the CBRC, together with colleagues from the Myotis Group (Romania) and the Museum of Natural History (Serbia), funded by the Conservation Leadership Programme, we demonstrated regular migration between maternity colonies in Serbia and hibernation sites in Romania.

Individuals ringed in northern Serbia were observed in several caves of the Semenic – Cheile Carașului National Park and of the Iron Gates Nature Park. The maximum recorded flight distance during the project was 89 km for the species.

The bent-winged bat is threatened by many human activities, including cave tourism (especially the development of caves for mass tourism), intensive forestry, and energy projects, for example wind farms where mitigation measures are not applied. Among European bat species, the bent-winged bat is predicted to experience a 10–15% contraction of its distribution range due to climate change. It is classified as Vulnerable (VU) by the IUCN at the European level, with declining populations.

How can we contribute to the protection of the bent-winged bat?

  • Avoid visiting caves or underground sites where hibernation colonies (December–March) or maternity colonies (June–July) are known.

  • If you encounter individuals or colonies in new caves, return in another season (e.g., spring or autumn), when sensitive colonies are not present. The cave will still be there.

  • Keep caves with colonies unmodified, without artificial lighting (including at the entrance) and without clearing vegetation at the entrance.

  • Protect deciduous forests and retain dead wood in forests.

  • Keep waters clean and avoid artificial lighting of water surfaces.

For more information about the species, and other themes, we recommend:

Since 2020 we also implement the European system, where Bat of the Year is designated for two years. Currently, the Bat of the Years 2026–2027 at the European level is Leisler’s bat (Nyctalus leisleri), a typical forest species that can migrate hundreds of kilometers between summer and winter roosts.

The photos above were provided by Dénes Dobrosi, Csaba Jére, Levente Barti and Szilárd-Lehel Bücs. Thank you!