Status: Endangered (44 FR 69208; November 4, 1979). Critical habitat not designated.
Description: The Ozark big-eared bat is the largest and reddest of the five subspecies of P. townsendii. The species is medium-sized and weighs from 0.2 to 0.5 ounces (5-13 g). It has very large (over 1 inch; 2.5 cm) ears that connect at the base across the forehead (see photo at left). The snout has prominent lumps above the nostrils (see photo below). The Ozark big-eared bat closely resembles the eastern big-eared bat, but has tan instead of whitish underparts and brown instead of gray dorsal hair.
Life History: The Ozark big-eared bat uses caves all year around. Migration distances between hibernation and summer caves are known to range from four to 40 miles (6.5-65 km). Big-eared bats mate in the fall and store the sperm during the winter. Pregnancy occurs in the spring at the end of hibernation. Ozark big-eared bats give birth to a single offspring. Young bats grow quite rapidly and are capable of flight at three weeks and are weaned by six weeks. Ozark big-eared bats feed on moths and other insects.
Habitat: Caves used by Ozark big-eared bats are located in karst regions dominated by oak-hickory forests. The temperature of hibernation caves ranges from 40° to 50°F (4-9°C). Maternity colonies are located in caves that range in temperature between 50° and 59°F (10-15°C). Ozark big-eared bats forage along forest edges.
Distribution: The distribution of the Ozark big-eared bat was probably limited to northwesten Arkansas, neighboring Oklahoma and Missouri. In Oklahoma, this subspecies is known to occur in Adair, Cherokee, Delaware, and Ottawa counties. There is a historical record for Sequoyah County.
Causes of Decline: The Ozark big-eared bat was probably never very common. The species is intolerant of human disturbance, which causes them to abandon favorite roosts. Disturbance of hibernating bats causes them to use valuable fat stores and increases the probability of starvation during the winter. Disturbance of maternity colonies can cause significant mortality of the young.
Recovery Needs: The top recovery needs of the Ozark big-eared bat include: 1) searching for and identifying additional maternity caves and hibernacula; 2) acquiring essential caves and foraging habitat in fee or easement; 3) enhancing management of caves owned or administered by the U.S. Fish & Wildlife Service; 4) enhancing management of caves owned by conservation organizations and States; 5) developing landowner agreements to protect caves and foraging habitat on private land; 6) constructing, regularly inspecting, and maintaining cave gates, fences, and signs where needed; 7) monitoring the population in summer and winter to determine if management efforts are effective; and 8) developing landowner and public support through an information / education program.
Other information: Gates or fences erected at cave entrances have been successful in protecting bats. A recovery plan was approved in 1984 and revised in March 1995.
Funds are currently available through the Healthy Forest Reserve Program (HFRP) in northeastern Oklahoma to protect and enhance forested wildlife habitat for threatened and endangered species and other declining wildlife populations. The federally listed species for habitat and population recovery activities include the gray bat, the Ozark big-eared bat, and the Ozark cavefish. The HFRP is administered by the Natural Resources Conservation Service (NRCS). The HFRP in Oklahoma is being implemented in coordination between NRCS, the U.S. Fish & Wildlife Service (USFWS), and Oklahoma Forestry Services (OFS).
