Bats of the United States and Canada

Allen’s Big-eared Bat, Idionycteris phyllotis

146 bats of the united states and canada ALLEN’S BIG-EARED BAT Idionycteris phyllotis Special Concern–United States Weight is 8-16 grams (0.3–0.6 ounce); wingspan is 31–35 centimeters (12–14 inches); distribution is the southwestern United States to central Mexico. This is a rather large bat with enormous ears and a unique pair of lappets projecting from the median bases of the ears over the top of the snout. When this bat is at rest, the huge ears lie along the back, often curled into the shape of a ram’s horn. Allen’s big-eared bat usually inhabits forested areas of the mountainous Southwest and is relatively common in pine-oak forested canyons and coniferous forests. It may also occur in nonforested, arid habitats . At most sites where this species occurs, cliffs, outcroppings, boulder piles, or lava flows are nearby. Day roosts may include rock shelters, caves, and mines. It leaves the roost only after complete darkness and usually flies about 10 meters (30 feet) above the ground. It emits loud calls at about 1-second intervals. Flight is slower than that of the free-tailed bats but swifter than most other bats. In close quarters, this species flies slowly, is highly maneuverable, is able to hover, and can fly vertically. In more open situations, it uses fast, direct flight. The sexes segregate geographically during summer, with females gathering into maternity colonies and males possibly remaining solitary, roosting elsewhere . Seasonal movements and winter whereabouts and activities are unknown. Allen’s big-eared bat primarily consumes small moths, but soldier beetles, dung beetles, leaf beetles, roaches, and flying ants also are eaten. One baby is born in June or July. Locally common, but rare over most of its range, it has been proposed for listing as threatened or endangered. recto runninghead 147 ...