Bat species - Vespertilio

I am making a tribute about the Bat species who gave their names on the "Batman Begins" Original soundtrack.
The first species is Vespertilio.
The Parti-coloured Bat or Rearmouse (Vespertilio murinus) is a species of bats in the family of Vesper bats. It is a medium sized bat.
hese bats hunt for their prey, for example mosquitoes, caddis flies, and moths, with ultrasonic sound of around 25-27 kHz. They hunt after twilight at heights of above 10 to 20 meters, for example in open landscape over streams and lakes and above forests or at street lights. In cold weather the bat may remain in its resting place.
There is not much known about the behaviour of parti-coloured bats, as they are quite rare. Female bats live in small groups, of about 50 animals, sometimes up to several hundred adult females. In Western Europe, male groups consist of about 250 animals and are found only during the spring and early summer. These bats migrate, and flights of up to 900 km were found. The furthest migration was determined at 1440 km in the year 1989.
Between October and March, the bats hibernate. They hibernate alone, and can bear temperatures down to -2.6 degrees Celsius.