Michael Durham / Western Long-eared Myotis (Myotis evotis) about to drink from a man-made guzzler, high-desert transition zone in the Deschutes National Forest, Oregon

Dietmar Nill / Long-fingered bat (Myotis capaccinii) in flight, Germany, captive.

Michael Durham / Western Long-eared Myotis (Myotis evotis) drinking at waterhole at night, Oregon

Michael Durham / Male Northern long-eared myotis / bat (Myotis septentrionalis) on a birch tree, North Cherokee National Forest, Tennessee, USA, June.

Michael Durham / Female Northern long-eared myotis / bat (Myotis septentrionalis) in flight at night, Cherokee National Forest, Tennessee, USA, June.

Michael Durham / Female Northern long-eared myotis / bat (Myotis septentrionalis) in flight at night, Cherokee National Forest, Tennessee, USA, June.

Michael Durham / Western long-eared bat (Myotis evotis) flying out of Pond Cave, Craters of the Moon National Monument, Idaho, USA, June.

Michael Durham / Long-legged myotis (Myotis volans) flying out of pond cave at night, Craters of the Moon National Monument, Idaho, USA, June.

Michael Durham / Western long-eared myotis (Myotis evotis) in flight, Deschutes National Forest, Oregon, USA, July.

Michael Durham / Western Long-eared Myotis (Myotis evotis) drinking from desert waterhole at night, central Oregon

Michael Durham / Western Long-eared Myotis (Myotis evotis) drinking from desert waterhole at night, central Oregon

Michael Durham / Northern Long-eared Bat (Myotis septentrionalis) male roosting, Cherokee National Forest, Tennessee