Bats of the United States and Canada

Southwestern Bat, Myotis auriculus

152 bats of the united states and canada SOUTHWESTERN BAT (Southwestern Myotis) Myotis auriculus Weight is 5–8 grams (0.2–0.3 ounce); wingspan is 26–28 centimeters (10–11 inches). Distribution is from Arizona and New Mexico to southern Mexico, but the winter range is unknown. The southwestern bat often occurs in ponderosa pine forests. It is also present from mesquite and chaparral through the oak forests into pinyon-juniper habitats and seems to reach its greatest abundance in areas of extensive rocky cliffs where water is available. No day roosts are known; night roosts include buildings, mines, and caves. Migrations may result in selection of different habitats during different seasons. This species is most active 1.5–2.0 hours after sunset but may show other peaks of activity during the night. Flight speed is about 13 kilometers per hour (8 miles per hour). Moths are the primary food; males eat significantly more moths than females. This species is known to glean insects, primarily moths with 3- to 4-centimeter (1- to 2-inch) wingspans, from buildings and tree trunks; it may land briefly on the substrate, then pick the insect off the surface. One baby usually is born in June or early July, but timing of birth shows considerable geographic variation. Life span is at least 3 years. The southwestern bat is common throughout its range. recto runninghead 153 ...