Two-colored bat ( Vespertilio murinus )
|Linnaeus , 1758|
Their chirping calls, reminiscent of birds , can be heard especially in autumn during the courtship season. It has a maximum height of 6.4 centimeters with a wingspan of 27 to 33 centimeters and a weight of 12 to 23 grams. It got its name from the short-haired, dense two-tone back fur. It is red to dark brown and silver white at the ends of the hair. The ventral side is also white to grayish. The ears, wings and face are black-brown. Their wings are narrow in relation to the body and the last caudal vertebra protrudes freely from the tail membrane. The ears are short, broad and rounded.
A characteristic of the two-colored bat is the presence of four teats on the female. No other European species has this characteristic. The maximum known age is twelve years.
Diet and hunting behavior
It hunts its prey, which includes two-winged birds , caddis flies and moths , with ultrasound tones around 23-26 kHz (main frequency). The prey flights take place after dusk at heights of 10 to 20 meters, among other things over open landscapes, rivers and lakes or around street lamps. In cold weather, the bat remains in its roost.
Columns in buildings are inhabited as summer quarters, mostly in intermediate roof quarters on tall buildings. The nurseries and the male roosts are usually found there. In winter, gaps in attics, on walls and rocks or in cellars and underground vaults are made.
Way of life
Since finds are rare, not very much is known about their way of life. The nursery roosts consist of small groups of around 50 females, but occasionally several hundred females. In Western Europe, mostly male roosts were found, which included around 250 animals. The entry holes are marked with glued-on droppings. It is a migratory species and flights of up to 900 km have been detected by ringing. The longest migration was recorded in 1989 at 1,440 km. This bat hibernates between the months of October and March and sleeps alone, rarely in groups. It can withstand temperatures down to −2.6 ° C.
Reproduction and birth
Twin births are the rule with the two-colored bat. In the breeding season from May to July, small nurseries are formed and usually two young are born.
It occurs in Central and Western Europe, in Asia and in the former countries of the USSR. There she lives in mountains, steppes and forest areas. In Europe especially in cities.
It is under species protection . As with other bat species, it is threatened by a lack of housing, insecticides and changes in habitat . Development and changes to buildings destroy many of the options available to them.