Scientific Name: Perastrellus hesperus
Canyon Bat, Dan Neubaum
The canyon bat is the smallest of Colorado's bats. It is easily recognized by its slow, erratic, butterfly-like flight. It has short, black ears, grayish brown pelage and a distinctive black mask making it one of the most attractive bats in North America. It weighs less than 4 g, little more than a penny. Other measurements are: wingspan, 190-215 mm; total length, 68-75 mm; and forearm, 29-31 mm.
The size of this bat can only be appreciated at close range. In the air, it appears fragile. The slightest breeze blows it off course or causes it to stall.
This species is found throughout the desert southwest. It ranges as far north as Washington state and east to Oklahoma. In Colorado, it is found at lower elevations on the Western Slope and in the extreme southeast.
This is a bat of the desert. It lives in arid canyons or dry shrub lands, near water. The canyon bat rarely roosts in human-made structures, nor does it seem to use mines or caves much except rarely as hibernacula. It does roost in both open and densely vegetated areas, using rock crevices in boulders, small cliff faces, and beneath rocky slabs. Although the canyon bat doesn't use the same roost day after day, it roosts in the same general area. Day and night roosts are different. This bat is non-migratory and sedentary. Hibernacula have been noted in several mines and a few caves but these bats likely use rock crevices as well. Predators are probably snakes, birds of prey and other bats.
Canyon bats eat small moths, beetles, mosquitoes and other flies. The canyon bat is thought to be the earliest bat to emerge and forage, sometimes before sundown, and again in early morning. The animals forage near canyon walls and among scattered boulders and shrubs. They remain active throughout the year. Foraging seems to be limited by winds above 10 mph.
One or two young are born in June each year. The canyon bat was confirmed to breed in Colorado when an infant bat was discovered on the floor of an abandoned building at Rio Blanco Reservoir, and a lactating female and a juvenile were observed at the Colorado National Monument. These bats may form small nursery colonies of 20-50 females and young or roost alone. The young are very small and exhibit the black mask at an early age. Males are segregated from females during much of the summer. Copulation occurs in the hibernaculum, followed by ovulation in spring.