Parti-colored bat
Vespertilio murinus
The parti-colored bat is a medium-sized bat species featuring a distinctive silvery-white frosted dorsal fur against a dark base. Its ventral side is sharply demarcated and colored whitish or grey, giving the species its characteristic name. It is known for its fast flight at high altitudes and long-distance migrations between summer and winter roosts. In late autumn, males are notable for their courtship songs, which are audible to humans and performed near tall buildings.
Details
Identification
Silvery-white frosted dorsal fur, sharply demarcated white underbelly, short and broad ears, and a wingspan of 27 to 33 cm.
Social behavior
Females form maternity colonies of 20 to 50 individuals, while males mostly live solitarily; in autumn, males exhibit territorial courtship behavior.
Diet
Feeds on small, soft-bodied insects such as midges, caddisflies, and moths, which are captured in open airspace.
Hunting strategy
Fast hunting flight at altitudes of 10 to 50 meters over open terrain, water bodies, or forest edges (aerial hawking).
Overwintering
Hibernation usually takes place in deep rock crevices or in crevices of tall buildings and bridges, often at great heights.
Ecology
Ecological role
Important insect population regulator in open airspace and prey for larger owl species.
Natural predators
Owls (especially barn owls), occasionally birds of prey or domestic cats in urban areas.
Competitor species
Other open-space foragers like the common noctule or the northern bat.
Ecosystem service
Biological pest control through the mass consumption of nocturnal insects.
Threats
Loss of roosts due to building renovations, collisions with wind turbines, and decline of prey insects caused by pesticides.
Scientific profile
Profile
Distinguishing features
Characteristic 'frosted' fur, short and broad ears with a rounded tragus. Narrow wings are noticeable in flight. Males exhibit species-specific display flight behavior with audible calls. Unique among European bats are the frequent twin births.
Habitat
Originally rocky landscapes and open forests. Today increasingly synanthropic in cities, using tall buildings (prefabricated buildings, high-rises) as substitute cliffs. Hunting grounds include open landscapes, lakes, and forest edges.
Diet
Insectivorous. Prefers small, soft-bodied insects such as non-biting midges (Chironomidae), caddisflies (Trichoptera), and aphids (Aphidina).
Protection & threats
Main threats
Loss of roosts due to energy-efficient building renovation, collision risk at wind turbines (especially during migration), use of insecticides in agriculture.
Population trend
Stable to unknown; due to the secretive lifestyle and long migrations, precise population trends are difficult to determine.
Conservation measures
Preservation of crevice roosts in buildings, installation of bat boxes, consideration of migration corridors in wind power planning, protection of insect habitats.