Serotine bat Eptesicus serotinus

The serotine bat (Eptesicus serotinus) is one of the largest bat species found in Germany, along with the greater mouse-eared bat and the common noctule. Is characterized by its distinctive face (dark mask), dark dorsal fur, light yellowish ventral coloration and relatively broad wings.

habitat descriptionIs considered relatively opportunistic. Can be found in forests, settlements, cities, parks, at the edge of forests, over meadows, along riverbanks, lakes and ponds.
quarters Nursery roosts of up to 60 individuals often use buildings and are found, for example, in roof trusses, in house crevices, false floors, behind shutters. Once occupied, roosts are usually maintained until the dispersal of the colonies in August. Individuals (mostly males) also in tree cavities and bat boxes. Males sometimes form colonies of up to 20 conspecifics. Hibernates from October - April mainly in buildings, but also underground and in rock crevices.
reproductionThe birth of one, rarely two young occurs from mid-June. They become independent at about four to five weeks. Sexual maturity probably does not occur until the second year. Mating occurs between August and October.
size - Head-torso length: 65-80 mm
- Forearm length: 48-58 mm
- Wingspan: 330-390 mm
weight 18-25 g
color/furElongated coat, usually black, dark or reddish brown on top, yellowish brown on underside. Face and ears dark.
ear shapeShort, tragus elongated, about ¼ of ear length, rounded at the end.
wing shapebroad
flight Buzzing and agile flight from constantly repeating paths. Also collect larger prey, e.g. cockchafer, from vegetation or the ground. Forage on poorly structured agricultural land as well as over structurally rich forest edges and livestock pastures, along houses and along bodies of water.
ultrasonic callsQuasi-constant frequency calls with start frequencies at 25 - 60 kHz and end frequencies at 22 - 27 kHz. Main frequency at 24 - 27 kHz. Slower and irregular call sequences leave a wet auditory impression and show similarity to the bicolored bat.
endangerment Endangered due to habitat loss, building renovations, and pesticide use.
IUCN (2021): least concern
Red List of Germany (2020): vulnerable