Parastrellus hesperus is the smallest bat in the United States, with a wingspan of 7-9 in (19-23 cm). This little cutie’s body color ranges from white to pale yellow to dark brown.Its face and ears are almost black. Canyon bats bats exhibit counter shading, being dark above and lighter colored below.
These bats can be found from southern Washington through the western United States and to southern Mexico.
The western pipstrelle is commonly the first bat out in the evening and the last bat to be seen after sunrise,being most active in the hours immediately following sunset and preceding sunrise and are usually not active during the overnight hours. These bats feed on insects, and have great flight maneuverability in order to chase them.
During the day, rock crevices serve as the preferred roosting sites for P. hesperus, although sometimes they can be found roosting in crevices inside mines. They may also be found in buildings.