Little Brown Bats
Order:
Chiroptera
Family: Vespertilionidae
Species: Myotis lucifugus
Bats are important members of the wildlife community and should not be intentionally harmed. They can become nuisances when they inhabit structures. The little brown bat, the big brown bat, and the Mexican free-tailed bat are three species of bats that commonly inhabit buildings and are collectively referred to as “house” bats. The little brown bat, one of the 15 species of mouse-eared bats, is common in Canada and the northern two-thirds of the United States.
Attics, basements and other
protected areas provide secluded harborages for bats.
Bats may move into structures when their natural habitats, such
as caves and hollow trees, are disturbed or removed.
Biology and Habits
Bats are classified in the order Chiroptera, meaning “hand-wing.” They are not rodents and do not gnaw surfaces, chew holes or tear insulation.
Little brown bats are about 3 inches (8 cm) in length with a wing span of 9 to 11 inches (23 to 28 cm). The adults are chocolate brown in color and weigh ¼ ounce. Smaller-sized juveniles may be almost black in color. Like the other house bats, this species has small eyes and large ears, each with a well-developed membrane, the tragus, which is an outgrowth from the inner base of the ear. The soft, naked skin of their wings connects fingers to the small hind legs. The two-clawed thumbs and the five toes of the hind legs are separate.
In the winter, colonies
of little brown bats usually hibernate in caves and mines located near
marshes, lakes and rivers. In
the spring and summer months, female bats form maternity colonies, usually
raising one young per female in dark, hot cavities such as attics, barns
and bell towers. Typically, the young are born and reared in June and July and
learn to fly in about three weeks.
Both the overwintering and nursery colonies may return to the same
location year after year.
Control
The presence of bats within buildings is evident from the accumulation of guano (droppings), as well as from the scraping and squeaking noises they make as they move. Occasionally, PCOs are called to remove an individual bat, but in most situations, PCOs must evict an entire colony. In either case, PCOs should implement non-lethal control measures. The use of pesticides to control bats is a violation of the Federal Insecticide, Fungicide and Rodenticide Act. Besides, it would increase the risk of bats falling to the ground and being handled by children or eaten by pets. Mechanical techniques such as glueboards and snap traps may only incapacitate the bats, thus increasing the risk of human contact.
Effective bat management programs incorporate inspection, exclusion or capture, and cleanup of guano. To identify the access points, such as chimneys and roof vents, that the bats use to gain entry into the building, observe bats at dusk as they leave their roost. Then, install check valves, excluders and screening as needed. Bats may persistently seek to re-enter a roost. Thus, follow-up inspections may be necessary to ensure that the bats cannot re-enter the building through missed access points. If the bats belong to a nursery colony, delay exclusion until the young can fly.
Bats can pose certain health
risks, so take proper precautions when working around bats.
Bats (like any other mammal) can contract rabies, their roosts
may harbor ectoparasites, and bat guano may contain fungal spores which
cause histoplasmosis, a lung infection.
PCOs can catch and remove individual bats while wearing heavy leather
working gloves. However,
do not handle bats with unprotected hands.
Workers removing guano and urine should wear safety equipment,
such as respirators and protective clothing.
(Courtesy of the National Pest Control Association.)