Bats (Myotis Lucifugus)
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University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln The Handbook: Prevention and Control of Wildlife Damage Management, Internet Center Wildlife Damage for January 1994 Bats (Myotis lucifugus) Arthur M. Greenhall Research Associate, Department of Mammalogy, American Museum of Natural History, New York, New York 10024 Stephen C. Frantz Vertebrate Vector Specialist, Wadsworth Center for Laboratories and Research, New York State Department of Health, Albany, New York 12201-0509 Follow this and additional works at: https://digitalcommons.unl.edu/icwdmhandbook Part of the Environmental Sciences Commons Greenhall, Arthur M. and Frantz, Stephen C., "Bats (Myotis lucifugus)" (1994). The Handbook: Prevention and Control of Wildlife Damage. 46. https://digitalcommons.unl.edu/icwdmhandbook/46 This Article is brought to you for free and open access by the Wildlife Damage Management, Internet Center for at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in The Handbook: Prevention and Control of Wildlife Damage by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. Arthur M. Greenhall Research Associate Department of Mammalogy BATS American Museum of Natural History New York, New York 10024 Stephen C. Frantz Vertebrate Vector Specialist Wadsworth Center for Laboratories and Research New York State Department of Health Albany, New York 12201-0509 Fig. 1. Little brown bat, Myotis lucifugus Damage Prevention and Air drafts/ventilation. Removal of Occasional Bat Intruders Control Methods Ultrasonic devices: not effective. When no bite or contact has occurred, Sticky deterrents: limited efficacy. Exclusion help the bat escape (otherwise Toxicants submit it for rabies testing). Polypropylene netting checkvalves simplify getting bats out. None are registered. Conservation and Public Education Quality bat-proofing permanently Trapping Information itself functions as a management technique. excludes bats. Available, but unnecessarily Initiate control before young are born complicated compared to exclusion or after they are able to fly. and bat-proofing. Repellents Other Methods Naphthalene: limited efficacy. Sanitation and cleanup. Illumination. Artificial roosts. PREVENTION AND CONTROL OF WILDLIFE DAMAGE — 1994 Cooperative Extension Division Institute of Agriculture and Natural Resources University of Nebraska - Lincoln United States Department of Agriculture Animal and Plant Health Inspection Service Animal Damage Control D-5 Great Plains Agricultural Council Wildlife Committee Introduction Conservation and Public Education Despite their ecological value, bats are relentlessly and unjustifiably perse- cuted. Bats are often killed because they live near people who needlessly fear them. These actions emphasize the need to educate the public on the rea- sons for bat conservation and why it is important to use safe, nondestructive methods to alleviate conflicts between people and bats. General sources of information on bats include states’ Cooperative Extension Services, uni- versities, government environmental conservation and health departments, and Bat Conservation International (Austin, Texas). Except where control is necessary, bats should be appreci- ated from a distance — and not dis- turbed. Identification and Range Bats, the only mammals that truly fly, belong to the order Chiroptera. Their ability to fly, their secretiveness, and their nocturnal habits have contributed Fig. 2. Little brown bat, Myotis lucifugus to bat folklore, superstition, and fear. They are worldwide in distribution and include about 900 species, second in number only to Rodentia (the rodents) among the mammals. Among the 40 species of bats found north of Mexico, only a few cause problems for humans (note that vam- pire bats are not found in the United States and Canada). Bats congregating in groups are called colonial bats; those that live a lone existence are known as solitary bats. The colonial species most often en- countered in and around human buildings in the United States are the little brown bat, (Myotis lucifugus, Fig. 2), the big brown bat (Eptesicus fuscus, Fig. 3), the Mexican free-tailed bat (Tadarida brasiliensis, Fig. 4), the pallid bat (Antrozous pallidus), the Yuma myotis (Myotis yumanensis), and the evening bat (Nycticeius humeralis). Fig. 3. Big brown bat, Eptesicus fuscus Solitary bats typically roost in tree foli- age or under bark, but occasionally are found associated with buildings, some only as transients during migration. D-6 Fig. 4. Mexican free-tailed bat, Tadarida brasiliensis These include Keen’s bat (Myotis keenii), the red bat (Lasiurus borealis), the silver-haired bat (Lasionycteris noctivagans), and the hoary bat (Lasiurus cinereus). Excellent illustra- tions of all bats discussed herein can be found in Barbour and Davis (1979), Wrist Knee Tuttle (1988), Geluso et al. (1987), and Ear Harvey (1986). Tail membrane Several species of bats have been included here, with significant inter- specific differences that need to be clarified if well-planned, comprehen- Tragus sive management strategies are to be Upper arm developed. Any problems caused by Calcar bats are limited to species distribution; Forearm Foot thus animal damage control personnel Thumb need not be concerned with every spe- Wing membrane cies. Colonial and solitary bats have obvi- ous differences that serve to separate Fifth finger Second finger the species into groups (refer to Fig. 5). Fourth finger Much of the descriptive material that Third follows is adapted from Barbour and finger Davis (1979). Fig. 5. Anatomy of a typical bat D-7 Colonial Bats ant of high temperatures; M. keenii E. fuscus frequently shares roosts may also share the same site. Sepa- with M. lucifugus in the East, and Little brown bat (Myotis lucifugus) rate groups of males tend to be with M. yumanensis, Taderida, and Recognition smaller and choose cooler roosts Antrozous in the West. Males typi- within attics, behind shutters, under cally roost in smaller groups or forearm — 1.34 to 1.61 inches (3.4 to tree bark, in rock crevices, and alone during the summer. 4.1 cm) within caves. wingspan — 9.02 to 10.59 inches (22.9 The big brown bat is one of the most to 26.9 cm) In the winter, little brown bats in the widely distributed of bats in the ears — 0.55 to 0.63 inches (1.4 to 1.6 eastern part of their range abandon United States and is probably famil- cm) buildings to hibernate in caves and iar to more people than any other foot — approximately 0.39 inches (1.0 mines. Such hibernacula may be species. This is partially due to its cm); long hairs on toes extend be- near summer roosts or up to a few large, easy-to-observe size, but also yond claws. hundred miles (km) away. Little is to its ability to overwinter in build- known of the winter habits of M. ings (attics, wall spaces, and base- Distribution (Fig. 6a) lucifugus in the western United ments). Its close proximity to Color States. humans, coupled with its tendency to move about when temperature The life span of little brown bats has Pale tan through reddish brown to shifts occur, often brings this bat been established to be as great as 31 dark brown, depending on geo- into human living quarters and years. The average life expectancy, graphic location. The species is a basements in summer and winter. however, is probably limited to only rich dark brown in the eastern Big browns also hibernate in caves, a few years. United States and most of the west mines, storm sewers, burial vaults, coast. Fur is glossy and sleek. Big brown bat (Eptesicus fuscus) and other underground harborage. Confusion may occur with a few other While E. fuscus will apparently “house” bat species. In the East, it Recognition travel as far as 150 miles (241 km) to hibernacula, the winter quarters of may be confused with Keen’s bat forearm — 1.65 to 2.01 inches (4.2 to the bulk of this species are largely (M. keenii), which has longer ears 5.1 cm) unknown. [0.69 to 0.75 inches (1.7 to 1.9 cm)] wingspan — 12.80 to 13.78 inches (32.5 and a longer, more pointed tragus to 35.0 cm) Big brown bats may live as long as 18 (the appendage at the base of the ears — with rounded tragus years. ear). In the West, it resembles the Distribution (Fig. 6b) Yuma myotis (M. yumanensis), Mexican free-tailed bat (Tadarida which has dull fur and is usually Color brasiliensis) smaller. However, the Yuma myotis and little brown may be indistin- From reddish brown, copper colored, Recognition to a dark brown depending on geo- guishable in some parts of the forearm — 1.42 to 1.81 inches (3.6 to graphic location. This is a large bat northwestern United States where 4.6 cm) without distinctive markings. they may hybridize. wingspan — 11.42 to 12.80 inches (29.0 Habits Confusion may occur with the evening to 32.5 cm); long narrow wings bat (Nycticeius humeralis) though the tail (interfemoral) membrane — does This is one of the most common bats latter is much smaller. not enclose the lower one-third to found in and near buildings, often one-half of the tail, hence the name Habits located near a body of water where free-tailed they forage for insect prey. Summer This hardy, rather sedentary species foot — long, stiff hairs as long as the colonies are very gregarious, com- appears to favor buildings for roost- foot protrude from the toes. monly roosting in dark, hot attics ing. Summer maternity colonies Distribution (Fig. 6c) and associated roof spaces where may include a dozen or so and up maternity colonies may include to a few hundred individuals, roost- Color hundreds to a few thousand indi- ing behind chimneys, in enclosed Dark brown or dark gray. Fur of some viduals. Colonies may also form eaves, in hollow walls, attics, barns, individuals may have been beneath shingles and siding, in tree and behind shutters and unused bleached to a pale brown due to hollows, beneath bridges, and in sliding doors.