Eurasian Serotine

The Eurasian serotine is a large bat with broad wings, quite large triangular ears, a dark face, and dark wing membranes. Its back varies from dark brown to yellow-brown and the underside is paler. Head-and-body length is about 58–80mm, wingspan 320–380mm, and weight 15–35g. Its very broad wings and characteristically slow, highly manoeuvrable flight with short glides are useful field characters. (Bat Conservation Trust)

Serotines commonly hunt along woodland edges, pasture, parks, and around buildings, taking large flying insects and often chewing beetles in flight. They may forage mostly within two kilometres of a roost but can travel farther. Summer roosts are frequently in buildings, either singly or in small groups, and the species can share structures with other bats. Mongolia-specific ecology was not described in the opened account. (Bat Conservation Trust; Wikipedia, general species account)