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Ozark big-eared bat

The Ozark big-eared bat (Corynorhinus townsendii ingens) inhabits caves and cliffs in Ozark forests [1]. Maternity caves and hibernacula occur in diverse areas, from large blocks of forest to small forest tracts interspersed with open areas. Maternity colonies are in cooler portions of caves from mid-April to late July. Solitary males usually occur in caves, talus cracks, and cliff overhangs during summer. Both sexes hibernate at cold locations in cold caves during winter months. The species currently occurs in eastern Oklahoma and northwest and north-central Arkansas. It is extirpated from southwest Missouri.

When listed as endangered species in 1979, the population was estimated at 100-200 bats [1]. Since then, additional maternity colonies and hibernacula have been located, and occupied caves have been given greater protection. The Oklahoma Bat Cave National Wildlife Refuge was established in 1985 and the Ozark Plateau National Wildlife Refuge in 1986. Other important caves have been protected by The Nature Conservancy, the National Speleological Society, and state agencies in Oklahoma and Arkansas. The population appears to have grown by an unknown degree between 1979 and 1987, then remained relatively stable between 1987 and 2004, with estimates from eight of the eleven censused years during this period showing between 1,600 and 2,000 bats [1, 2, 3].

Oklahoma typically supports 1,600-1,800 of the estimated 2,000 bats [1, 2, 3]. As of 1995, ten caves in Adair and Delaware counties, Oklahoma were considered "essential" [1]. Forty additional Oklahoma caves were classed as "limited use/transient" and eight as "possible use". Four caves in Marion and Washington counties, Arkansas were considered "essential", seventeen as "limited use/transient" and twelve as "possible use". The smaller Arkansas population (about 200 bats) appears to have experience a real declined between 1978 and 1998, though the known number has remained relatively stable due to newly discovered caves [4].

[1] U.S. Fish and Wildlife Service. 1995. Ozark Big-Eared Bat Corynorhinus townsendii ingens (Handley) Revised Recovery Plan. Tulsa, OK.
[2] Harvey, M.J., R.K. Redman and C.S. Chaney. Endangered Bats of Arkansas: Distribution, Status and Ecology (2003-2004). Annual Report to Arkansas Game and Fish Commission, Project Number W-56-R.
[3] Currie, R. 2000. Federally listed threatened and edangered species of concern to mining. Paper presented at Bat Conservation and Mining: A Technical and Interactive Forum, November 14-16, St. Louis, MO.
[4] Arkansas Game and Fish Commission Strategic Non-game Management Plan. Prepared by the Nongame Mammal Team, Wildlife Management Division, and Arkansas Game and Fish Commission. See http://www.agfc.state.ar.us/pdf/critters/nongame_mammal_2001.pdf

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