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Nycticeius humeralis (Rafinesque, 1818)Evening Bat
Federal Protection: No US federal protection
State Protection: No Georgia state protection
Global Rank: G5
State Rank: S5
SWAP High Priority Species (SGCN): No
Element Occurrences (EOs) in Georgia: 0
Habitat Summary for element in Georgia: Georgia habitat information not available
Evening bats have short, sparse, medium to dark brown hair and black ears. Their average length is 87 mm (3.4 in) and a wingspan of 11 in (280 mm). Evening bats weigh between 6 and 14 g and have a forearm 34 to 38 mm (3.4-3.8 cm) long.
The evening bat is commonly confused with the big brown bat due to its fur color and broad muzzle. However, the evening bat is much smaller and does not have a keeled calcar. The evening bat's rounded tragus distinguishes it from all other small bats except the eastern pipistrelle, which has tri-colored rather than bicolored dorsal fur. The evening bat also has just two upper incisors instead of the four typical of all myotis.
The evening bat is a forest-dwelling species that roosts in tree crevices and behind loose bark, as well as in buildings. This species rarely enters caves but does participate in swarming activities at some cave entrances in late summer. They have been recorded using tree hollows, but as forests have been cut, many have moved into wooden buildings.
Evening bats are insectivorous, feeding on flying ants, spittlebugs, June beetles, Japanese beetles and moths.
A true forest bat, the evening bat is almost never encountered in caves. It forms nursery colonies in hollow trees, behind loose bark, and sometimes in buildings and attics. Some of these maternity colonies are quite large, containing several hundred individuals. Females usually have twins weighing 2 g each at birth. Evening bat pups are one of the largest newborn mammals compared to the size of their mother. Pups reach maturity after one year. The Evening Bat has a relatively short life span for a small insectivorous bat, apparently living about two to five years in the wild.
Classic survey methods for evening bats bats include mist-netting and the use of ultrasonic bat detectors. Mist netting surveys in Georgia should follow guidelines laid out on our Bat Survey Guidance webpage (http://www.georgiawildlife.com/BatSurveyGuidance).
Evening bats range from Pennsylvania west to southeastern Nebraska south to eastern and southern Texas and east Florida. In Georgia they can be found throughout the state.
Habitat loss from cutting of old-growth timber is a major threat to the evening bat as well as when wooden barns and old buildings are replaced by structures that bats cannot use.
There are no state-level protections for this species.
Management recommendations include the building of artificial roosts to counter the loss of habitat. Bat houses are built to accommodate 14 different species of North American bats and offer them a comfortable and safe place to live when their natural environment is being taken over by human disturbance. When constructing a bat house, guidelines provided by Bat Conservation International (BCI) should be met. You can find more information on our website at https://georgiawildlife.com/BatHouses.
Bat Houses, www.batcon.org/resources/getting-involved/bat-houses.
“Evening Bat (Nycticeius Humeralis).” RSS, tpwd.texas.gov/huntwild/wild/species/evening/.
Kunz, T. 1999. Evening bat| Nycticeitius humeralis . Pp. 117-118 in D Wilson, S Ruff, eds. The Smithsonian Book of North American Mammals. Washington, D.C.: The Smithsonian Institution Press in Association with the American Society of Mammalogists.
“Sunset/Sunrise Survey - Surveys.” Bat Conservation Trust, www.bats.org.uk/our-work/national-bat-monitoring-programme/surveys/sunset-sunrise-survey.
Web, Animal Diversity. “Critter Catalog.” BioKIDS, www.biokids.umich.edu/critters/Nycticeius_humeralis/.
S. Krueger, March 2020