Photo Credit: Merlin D. Tuttle, Bat Conservation International
SCIENTIFIC NAME: Nycticeius humeralis
DESCRIPTION: A rather small (0.25-0.52 ounces) brown bat with short, dull brown fur; and blackish ears and wings. The average total length is about 3 to 4 inches, and wingspan is 10 to 11.5 inches. Evening bats have a rounded tragus, unlike Myotis bats where the tragus is pointed. This species superficiously resembles a small big brown bat.
DISTRIBUTION: This species can be found in most of the southeastern, eastern and midwestern United States, south from the Great Lakes to northern Mexico. In Alabama they are found statewide and are considered common.
HABITAT: Evening bats are considered forest bats, but may also be found in urban areas with appropriate habitat. It inhabits buildings, under loose bark and tree cavities in the summer. It is almost never found in caves. Nursery colonies may be found in hollow trees, behind loose bark, and sometimes in buildings and attics. The winter habitat is not well known.
LIFE HISTORY AND ECOLOGY: Evening bats emerge soon after dusk and forage on a large variety of small nocturnal insects including flying ants, spittle bugs, June beetles, Japanese beetles and moths. Breeding occurs in the fall with delayed fertilization until spring. Young are born in May and June in sex-segregated nursery colonies of up to several hundred individuals. Litter size is usally two. They are slow, steady flyers and though they typically do not use caves, individuals may sometimes swarm by cave entrances with other species. Some population studies have found the lifespan as few as two years, while other studies found five-year lifespans.
To date (2012) the affliction White Nose Syndrome has not been documented in this species. As with most wild mammals, the evening bat can and does contract and transmit rabies. Though the incidence of rabies in any bat is very low, any bat that appears sick or cannot fly should be avoided. The evening bat is a very beneficial species and – like all Alabama’s bats – provide a natural means of insect control.
PREPARED BY: M. Keith Hudson, Wildlife Biologist, Alabama Wildlife and Fisheries Division.