Needles Field Office

Bats - Turning a Hole into a Home

Mine Adit before the installation of a bat gate; Photo Credit: BLM
Photo Credit: BLM
A mine adit after the installation of a bat gate; Photo Credit: BLM
Photo Credit: BLM
Mine Adit before and after installation of a bat gate



Needles Field Office Bat Monitoring Program

Many myths exist about bats from they bite humans and turn us into vampires, to they get tangled up in your hair.  These are however just myths, and the truth is that bat populations have been in the decline due to negative human impacts.

The most significant threats to bat species are persecution by humans and loss of habitat.  Vandalism and disturbance of roosting sites seriously threaten remaining populations.  Bats burn up important fat reserves when aroused during hibernation; a healthy adult bat can typically only tolerate two to three arousal disturbances per winter.  Maternity roosts are also very sensitive to disturbance. Females may abort their fetus if disturbed during maternity roosting in the spring.  Though bats are long-lived, they reproduce slowly. Most bats only rear one young per year.  Thus, population recovery from disturbance can take a long time.

Bats in the desert choose roosting sites that might surprise you.  They often roost in abandoned mines and associated structures.  The Needles Field Office has done several projects in recent years to protect bat habitat, as well as humans from the hazards of abandoned mines.  These projects consist of constructing bat gates.  A bat gate has slats big enough for bats to fly out and hunt for insects at night, but small enough to prevent humans from entering the mine.  Abandoned mines serve as roosting habitat for several bats considered "BLM Sensitive" and "California Department of Fish and Game (CDFG) Species of Special Concern."  More than half of the 45 bat species in the U.S. are in rapid decline or already listed as endangered.  Two-thirds of these bat species roost in mines.

Bats are monitored by members of the Needles Field Office staff using night vision goggles, a NightShot video camera, and a device that records acoustic bat calls.

Next time you see an abandoned mine in our resource area, think about what interesting creatures it may be a home to, and PLEASE, DO NOT ENTER IT.  Leave bats to their peaceful slumber.




Bureau of Land Management
Needles Field Office
1303 S Highway 95
Needles, CA 92363
Phone: (760) 326-7000
Fax: (760) 326-7099
Office Hours: 7:30 a.m. - 4:00 p.m., M-F
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