Antrozous pallidus
(Pallid Bat)

Description:
The dorsal fur is yellowish to pale-creamish brownish. The ears are large, up to five-eights of an inch (=15mm) across at the base and broadly rounded along the margin. The tragus is less than one-half of the length of the ear.

Range:
Southern British Columbia south along the western and southern section of Idaho, most of Wyoming, and south west through Utah, Colorado, Kansas, western Oklahoma, Texas and Mexico, then west including Baja California and along the Pacific Coast through California, Oregon and the central portion of Washington. Specimens have been collected or identified at roosts in seven counties in Idaho.

Habitat:
Pallid bats frequent arid or semi-arid shrub steppe , grasslands and, to a lesser extent, higher elevation coniferous forests. They roost in rock crevices, mines, hollow cavities in trees, and occupied or vacant buildings. They may also roost in objects placed on the ground.

Diet:
This species usually feeds on ground dwelling arthropods, gleaning scorpions, Jerusalem crickets, cicadas, beetles or smaller insects associated with flowers and cactaceous plants. Lesser amounts of flying insects appear to be consumed.

Ecology:
Pallid bats are gregarious and may feed together at sites containing abundant prey. Because they have larger eyes than bats in the genus Myotis, feeding is likely aided by both sight and passive sound that indicates the location of moving prey. Maternity colonies may be large and move in relation to temperature conditions. Warmer temperatures are selected at maternity roosts. The winter ecology of this species is poorly documented. Individuals do not appear to migrate or to hibernate for long periods and individuals have been observed flying during cold weather. Night roosting individuals emit audible calls that likely indicate the location of a group to other flying individuals but the exact function of these calls is poorly understood.

Species is gregarious . Usually forms clusters in diurnal roosts (Yuma myotis may roost among pallid bats). May also gather in night roosts that are frequently near, but separate from, day roosts (40-75% of time away from diurnal roost may be spent at night roosts). Usually roosts in rock crevice or building, less often in cave, tree hollow, or mine (in Oklahoma, night roosts are typically in caves). Emerges from day roost relatively late; foraging peaks at beginning and end of nocturnal activity cycle. Captures prey on ground, after an aerial search; also takes prey in flight, within few meters of ground vegetation. Bimodal foraging and audible communication is known. Species is largely inactive in winter, and is believed to hibernate (in Idaho, species is migratory).

Reproduction:
Breeding occurs between October and February and sperm is stored until spring ovulation . Maternity colonies form in May or June. From one to three pups are born likely depending on the parity of the female.

Copulation usually occurs from October-December; fertilization takes place in spring. In U.S., usually 2, but sometimes 1, young are born from: late May-early June in California; mostly late June in Kansas; and probably early May to mid-June in Texas. Young fly at 6 wk, and are weaned in 6-8 wk. Maternity colonies are usually small, but may include up to 200+ adults, including some adult males.

Conservation:

Status:	Unprotected nongame species
Global Rank:	G5
State Rank:	S1

Important State References:
Keller, B.L. 1987. Analysis of the bat species present in Idaho, with special attention to the spotted bat, Euderma maculatum. Dept. Biol. Sciences, Idaho St. Univ., Pocatello. 25pp.