Serotine bat
Eptesicus serotinus
The serotine bat is one of the largest European bat species, with a wingspan reaching up to 38 cm. It possesses long, silky fur that is smoky brown on the back and yellowish-brown on the underside. The species is a typical house-dweller, preferring crevice roosts in buildings or attics. Its flight is characterized by slow, fluttering movements, often hunting at low altitudes.
Details
Identification
Large, dark ears with a rounded tragus; powerful jaw; the tip of the tail extends 3-5 mm beyond the tail membrane.
Social behavior
Forms maternity colonies of 10 to 100 females in summer; males usually live solitarily during this period.
Diet
Feeds on beetles (e.g., cockchafers, dung beetles), moths, and other larger flying insects.
Hunting strategy
Slow searching flight at heights of 2-10 meters along structures or perch-hunting from elevated spots.
Overwintering
Hibernation in deep wall crevices, rock fissures, or cellars at temperatures between 2 and 6 degrees Celsius.
Ecology
Ecological role
Important insect predator; contributes to the biological control of agricultural pests.
Natural predators
Barn owl, tawny owl, domestic cat, and various marten species.
Competitor species
Other house-dwelling bat species and the common noctule in similar hunting habitats.
Ecosystem service
Biological pest control by consuming large quantities of insects per night.
Threats
Loss of roosts due to energy-efficient building renovations, pesticide use in agriculture, and wind turbines.
Scientific profile
Profile
Distinguishing features
Large bat species with broad wings. The tragus is short, rounded, and curved inwards (not mushroom-shaped). The tip of the tail extends about 3-5 mm beyond the tail membrane. The ears are relatively short and broad.
Habitat
Typical synanthropic species. Prefers open to semi-open landscapes, gardens, parks, and village structures. Often hunts along forest edges, hedgerows, over pastures, or under streetlights.
Diet
Insectivorous. Main diet consists of beetles (Coleoptera, e.g., cockchafers, dung beetles), moths (Lepidoptera), and flies (Diptera).
Protection & threats
Main threats
Renovation of old buildings (loss of roosts), use of insecticides (food shortage), collisions with wind turbines, loss of roosts due to energy-efficient building renovation.
Population trend
Regionally varying in Germany; often stable, but local declines recorded due to loss of roosts and food shortage.
Conservation measures
Preservation of entrance openings during renovations, avoidance of toxic wood preservatives, promotion of insect-rich habitats (avoidance of pesticides), installation of bat boxes.