Bats of the United States and Canada

Canyon Bat, Parastrellus hesperus

136 bats of the united states and canada CANYON BAT (formerly Western Pipistrelle) Parastrellus hesperus Weight is 3–6 grams (0.1–0.2 ounce); wingspan is 19–22 centimeters (7–9 inches); distribution is from southern Washington to southern Mexico. The genus of this bat recently was changed from Pipistrellus to Parastrellus. There is no bat in the genus Pipistrellus in the United States or Canada (there were 2), but there are 29 species of Pipistrellus elsewhere in the world. This species is now called the canyon bat. However, researchers will likely continue to refer to them as “pips.” The canyon bat is one of the smallest bats in the United States. Primarily a desert species, it inhabits a variety of habitats from rocky canyons, cliffs, and outcroppings to creosote bush flats. Day roosts usually are in rock crevices, but may be beneath rocks, in burrows, in mines, or in buildings. It tends to roost singly or in small groups; a maternity colony of 12 individuals is the largest known group of this species. In winter, the canyon bat has been found hibernating in mines, caves, and rock crevices. Among the most diurnal of bats, it often begins foraging flights before sunset and may remain active well after dawn. Except for lactating females, which may be active throughout the night, these bats usually cease early evening activity within 1–2 hours after sunset. The flight is fluttery and among the slowest and weakest of all our bats. A slight breeze can bring these bats to a standstill, and a stronger wind may cause them to seek shelter. This bat forages on swarming insects about 2–25 meters (5–80 feet) aboveground and consumes about 20% of its body weight per feeding. Prey items include caddisflies, stoneflies, moths, small beetles, leaf and stilt bugs, leafhoppers, flies, mosquitoes, ants, and wasps. Twins are born in June or July, after a gestation of about 40 days. Newborn bats weigh less than 1 gram (0.03 ounce), but they grow quickly. Juveniles begin to fly at about 1 month of age. The canyon bat is relatively common throughout most of its range. recto runninghead 137 ...