The brown long-eared bat (Plecotus auritus) is a medium-sized species with very large (long) ears. It is a distinctly forest species, which is able to detect and prey on insects on the surface of leaves due to its particularly fine hearing.
Mainly in forests of various types, also monocultures. Also found in meadows and parks.
Nursery colonies of up to 50 individuals roost from April to September, mainly in tree cavities, under bark, crevices of buildings, also in bat boxes. Colonies change roosts regularly. Males are usually solitary. They are more eager to explore new roosts compared to other species. Hibernate from November to March in underground basements, caves, but also in rock and building crevices, and tree cavities. They also leave winter roosts in warm weather to hunt.
Birth of only one young usually occurs between mid-June and mid-July. At about six weeks, flight ability is fully developed. Sexual maturity usually does not occur until the second year of life. Mating groups form from about the beginning of August. The most intensive swarming period takes place at caves until October, another but weaker swarming phase occurs between February and April.
- Head-torso length: 42-50 mm - Forearm length: 35-43 mm - Wingspan: 240-290 mm
6-9 g
Upper side gray-brown, partly with red tinge, underside gray-yellow. Around the eyes medium brown coat color, around the muzzle flesh-colored. The face is lighter with short hairs, ears and tragus light. Hind feet and toes strongly hairy.
There is a pair of bulging glands on the nostrils.
Very long. Are placed behind the wings during torpor in hibernation, so that only the lanceolate tragus is visible, which itself resembles a small ear. The tragus itself is pale yellowish/greyish.
Broad and short, roundish.
Rather slow fluttering or shaking flight. Catch insects in flight or collect insect prey directly from leaves while hunting, recognizing them by their movements and resulting rustling sounds, but also visually. Smaller prey is consumed while still in flight, larger ones are taken to feeding sites. Flying from the ground to the canopy of trees. Prey consists largely of moths, beetles, grasshoppers, and arachnids. Flying out usually only in complete darkness. Swarming during morning return flight about 30 min before roosting.
Frequency modulated, dry calls with start frequencies at 45 - 60 kHz and end frequencies at 18 - 13 kHz. Main frequency at 25 - 35 kHz. Call intervals are very variable, therefore very unrhythmic. Because the calls are very quiet, they leave a "whispering" auditory impression that is unique compared to the species of all other genera.
Threats are primarily due to loss of roosts, habitat alteration, and the use of wood preservatives (when they roosts for example in churches). Because of their slow, near-surface flight, they are the most common species killed by road traffic. There are also observations that long-eared bats are often found dead on glue flycatchers, which turn out to be deadly traps when the bats try to collect supposed prey from them. Red List of Germany (2020): Endangered. IUCN (2019): Least Concern.