Bats of the United States and Canada

Pocketed Free-tailed Bat, Nyctinomops femorosaccus

112 bats of the united states and canada POCKETED FREE-TAILED BAT Nyctinomops femorosaccus Weight is 10–14 grams (0.4–0.5 ounce); wingspan is 34–35 centimeters (13–14 inches); distribution is from the southwestern United States to southcentral Mexico. The common and scientific names refer to a shallow fold of skin that forms a pocketlike structure on the underside of the interfemoral membrane near the knee. The pocketed free-tailed bat occurs in arid lowlands of the desert Southwest, and primarily roosts in crevices in rugged cliffs, slopes, and tall rocky outcrops. Colonies are small, usually fewer than 100 individuals. In day roosts, these bats squeak or chatter much of the time. They generally leave the roost well after dark. When first taking flight, pocketed free-tailed bats produce shrill, sharp, high-pitched chattering calls that may continue while the bats are in flight. As with other free-tailed bats, flight is swift and lacks the fluttering characteristic of many other bats. At stock ponds and other water sources, they fly swiftly about the pool, making distinctly audible whistling and fluttering sounds with their wings. To drink, these bats will hit the water hard while in flight and scoop up a mouthful of water. Moths are common prey; other foods include beetles, flying ants, flies, leafhoppers , crickets, stinkbugs, lacewings, and grasshoppers. One baby is born in late June or July. The pocketed free-tailed bat is uncommon in the United States. recto runninghead 113 ...