Pocketed Free-tailed Bat (Nyctinomops femorosacca)
- Protection Status Notes
- This species currently is not listed as Threatened or Endangered. Little is known about population trends in Texas.
- Like all molossids ( free-tailed bats), Nyctinomops femorosacca has a free‑tail which extends beyond the edge of the interfemoral membrane. With a forearm of 45‑49 mm, it is smaller than all other North American molossid species except Tadarida brasiliensis. It is slightly larger than T. brasiliensis and, unlike T. brasiliensis, has its ears joined at the midline.
- Life History
- The species forms maternity colonies, and females bear one young in late June or July. Lactating females have been taken between 7 July and 8 August, and volant juveniles recorded on 7 August. Owls and snakes have been documented preying on this species. Little is known about population dynamics, seasonal movements, or ecology.
The pocketed free‑tailed bat is colonial and roosts primarily in crevices of rugged cliffs, high rocky outcrops and slopes. It has been found in a variety of plant associations, including desert shrub and pine‑oak forests. The species may also roost in buildings, caves, and under roof tiles.
N. femorosacca forages mainly on large moths, but its diet includes small moths and beetles, with small amounts of a variety of other insects.
- N. femorosacca occurs in western North America, from southern California, central Arizona, southern New Mexico, and western Texas, south into Mexico including Baja California. The species is thought to be non‑migratory. The known altitudinal distribution is from near sea level to about 7,300 feet. Breeding populations have recently been identified in southern California.
The pocketed free-tailed bat is known in Texas only from Big Bend National Park, Brewster County.
- Threats and Reasons for Decline
- No known treats to the species have been identified to date. However, some of the general threats to bats could apply to N. femorosacca. These could include impacts to foraging areas from grazing, riparian management, the use of pesticides, disturbance to roost sites, or any activities that impact cliff habitat. More information on the ecology of this species is required before threats can be more fully delineated.
- Ongoing Recovery
- These bats require large surfaces of open water in order to drink. Such sites are declining in number in many places, representing a threat to several of the least maneuverable free-tails.
- Information is needed on N. femorosacca regarding roosting ecology, foraging ecology, seasonal movements, and breeding colony distribution. Little appears to be known about the echolocation calls of this species, and documentation is needed for comparison with other molossid species.
Additional details can be found in the online version of The Mammals of Texas for the Pocketed Free-tailed Bat