Barbastella barbastellus (Schreber, 1774)
Vespertilionidae

Near Threatened

Description

Medium-sized bat, with a body length ranging from 45 to 60 mm, a forearm length between 36 and 43 mm, a wingspan between 255 and 300 mm, a tail length between 36 and 52 mm, ears up to 20 mm, and a weight between 5 and 14 g. It shows slight sexual dimorphism, with males usually being smaller than females. The species is unmistakable due to its short muzzle with nostril fissures reaching the lips, and unique trapezoidal ears that, when joined at the center of the head, point forward. The tragus is long and rounded, narrowing at the tip. The skin is typically dark brown, almost black. The fur is silky and black or dark brown, with yellow or white tips, giving it a fawn-like appearance. In the Canary Islands, females tend to be more brownish, and males are darker, with neither displaying the fawn-like coloration. Juveniles typically have slightly darker coloration than adults. Part of the wings and uropatagium are covered with fur.

Distribution

It is distributed throughout much of central Europe but with many gaps in the Mediterranean area. The northernmost point of its distribution is in Sweden, with a single record in Norway, and to southern England. It is also found in the Balearic Islands, Corsica, Sardinia, Sicily, the Canary Islands, Morocco, Turkey, Anatolia, the Caucasus region, and Iran. In Belgium, the Netherlands, and Norway, the species is likely extinct.

Roosts and phenology

In summer, roosts are typically in forests, behind tree bark, in trunk crevices, and even in flat, narrow bat boxes. Natural roosts are often found in mature forests with an abundance of dead trees and cavities, preferably in oak groves, beech forests, and spruce forests. The roosts are usually located at heights between 8 and 10 meters. Occasionally, they seek refuge in human structures such as old buildings or barns. Roosts for breeding in buildings can house up to 100 females, while those in trees usually have around 10-20 females. Breeding colonies in trees often change roosts frequently. One or two pups are born in mid-June and are weaned by six weeks of age. Females become fertile from the first year, and mating occurs in swarming caves, mainly from late August, although it can extend from September to November, depending on latitude.

This species is not considered migratory. In winter, they also roost under tree bark but more frequently use underground roosts. It is a highly cold-resistant species and typically hibernates at the entrance of these cavities, with temperatures close to freezing. These underground roosts can contain thousands of individuals, with the largest recorded in Slovakia and Poland housing 8,000 bats.

Habitat and diet