Evening Bat

(Nycticeius humeralis)

Evening Bat
Evening Bat by James Kiser

Kentucky Status:  Special Concern

Description: This bat is remarkably similar in appearance to the big brown bat. It has glossy brown fur and blackish face, wings and feet. It typically reaches only 4 inches in length with a wingspan of about 10.5 inches. Unlike the big brown bat, this species also does not have a keeled calcar. It can be easily distinguished from similarly sized Myotis species by its short, blunt, slightly curved tragus.

Range:  The evening bat occurs locally throughout the eastern United States from central Pennsylvania and the southern Great Lakes, west to north-central Iowa, southeastern Nebraska, central Kansas, Oklahoma and Texas; it is much more widespread and common in the southern part of that range.

Kentucky Occurrence Summary:  This species is relatively common only in the western third of Kentucky, with scattered records as far east as Floyd County on the Cumberland Plateau. The evening bat was previously believed to be a summer resident, migrating southward in fall, but new research suggests that some could overwinter in Kentucky.

Distribution in Kentucky:  See Map

Habitat and Life History:  Evening bats primarily roost in hollow trees and under loose bark but many nursery colonies have been found in buildings. There are records of the bat using other man-made structures like bridges and cisterns. They are not typically associated with caves. Most are believed to winter to the south of Kentucky where they may remain active throughout the year. These bats likely return to Kentucky during the latter part of April and form summer colonies in both natural and artificial sites. Females gather into maternity colonies while males roost separately, perhaps singly. Two pups are typically born to each female during June and are on the wing within a few weeks. Evening bats remain in Kentucky into September or October. There are a few records later in the year as well as new research that suggest some individuals may overwinter here. This species forages in a variety of semi-open habitats from wetlands and stream corridors to woodland edges and parks. They prey upon a great variety of flying insects from small beetles to flies and moths.

Threats:  Although the evening bat has adapted to some of the changes that humans have brought to the landscape, the conversion of forested wetlands to agricultural use has resulted in a significant decrease in prime roosting and foraging habitat. Logging activities also have resulted in a loss of prime roosting trees in some situations.

Evening bat (top) and big brown bat (bottom)
Evening bat (top) and big brown bat (bottom)
Photo by James Kiser