Atlas der Säugetiere Nordrhein-Westfalens

Wasserfledermaus

2711 entries

Daubenton′s bat

Rote Liste NRW: G Gefährdung unbekannten Ausmaßes

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Myotis daubentonii

With a head and body length of 45-55 mm, a forearm length of 33-42 mm and a weight of 6-10 g, Daubenton′s Bat belongs to the smaller bat species of Europe. Its fur is dense and the colour of the upper side is a cold brown. The underside is a noticeably lighter, grey-white. Ears and flight membranes are coloured dark grey-brown; the snout is flesh-coloured. Daubenton′s Bats have rather short ears. During disturbances, even in animals that are fast asleep, the ears are bent horizontally to the side. Especially in juvenile Daubenton′s Bats, a bluish-black pigment spot on the lower lip is especially pronounced. Another conspicuous characters are the relatively large feet.
Daubenton′s bats are often counted among the so-called forest bats, because in their summer habitat, they use tree cavities for their nursery roosts. For this they prefer old woodpecker and rot cavities in English Oaks and European Beech. But they also move into bat boxes or expansion gaps in bridges. Sporadically, nursery colonies can even be found in subterranean roosts or in buildings. In North Rhine-Westphalia, nursery roosts usually encompass 20-40 adult females. The males, too, occasionally form group roosts in summer, but frequently they spend the summer solitarily.
Daubenton′s Bats prefer hibernacula with a very high humidity and temperatures of about 3-8°C. These conditions are available, for example, in caves, mines, well shafts and ice cellars and in some bunkers. Here the animals are frequently associated with other species of the genus Myotis. In these roosts, the bats don′t just sleep; rather, part of the mating also takes place here. In front of some of these subterranean spaces the so-called swarming behaviour of Daubenton′s Bats can be observed.
In North-Rhine-Westphalia, Daubenton′s Bats are widely distributed. Focal points with nursery colonies can be found in the area of structured forest-and-water assemblages with a sufficient share of old growth and snags. To persist in an area, the presence of insect-rich and un-illuminated water bodies with an open and quiet water surface and a sufficient supply of suitable tree cavities must be available for the species. Furthermore, suitable hibernacula must be within easy reach.
For North-Rhine-Westphalia, significant hibernacula are known from the highlands of Eastern and Southern Westphalia and the Eifel. There are also well-occupied hibernacula in the lowland. A roost is known from Münsterland (Coesfeld County) where 3000 Daubenton′s Bats hibernate. Daubenton′s Bats can migrate between the summer habitat and their hibernacula. For NRW, distances of up to 60 km are documented.
Whereas in past decades for some bat species an increase in number was documented, the population of Daubenton′s Bats has not significantly changed during the same time span.

Author

Lena Grosche

Citation

Grosche L (2024): Wasserfledermaus (Myotis daubentonii).In: AG Säugetierkunde NRW — Online-Atlas of the mammals of North Rhine-Westphalia. Downloaded from saeugeratlas-nrw.lwl.org on 2024/05/18