New Jersey's primary hibernaculum for little brown bats receives new attention--
By Jo Ann Frier-Murza
Along-abandoned mine shaft in rural New Jersey has been known as a wintering spot for as many as 20,000 little brown bats (Myotis lucifugus). Last winter a concerned citizen called the New Jersey Endangered and Nongame Species Program (ENSP) to report that the opening had been covered with a foot-thick wall of concrete. He pleaded for help for the thousands of entombed, hibernating bats. We immediately began a series of phone calls and personal contacts to reopen the entrance. Bat Conservation International was instrumental in providing information and referrals to people who could advise us on gating procedures and conservation measures.
The mine was first brought to our attention after a 1980 survey for endangered Indiana bats discovered that, while no Indiana bats were found in the mine, it could be one of the top little brown bat colonies in the United States. Dr. John Hall of Albright College, who conducted the survey, recommended that the original gate be replaced with a new design to improve habitat for the bats. A heavy boilerplate and angle-iron barrier with a small opening torched through it had been covering the entrance for at least 15 years. Unfortunately, funding for nongame wildlife was pitifully small at that time, and the hibernaculum didn't receive any further attention until the urgent phone call early last year.
The current landowner, a major development corporation, had been in the process of sealing all vertical shafts and included the horizontal shaft that the bats used because they wanted to end vandalism and liability problems. They were sympathetic to the needs of the bats but weren't aware of what those needs might be. They had left an opening in the concrete measuring only about 6 inches by 17 inches. Worse yet, the concrete was placed directly against the original barrier which consisted of crossed four-inch angle irons. The amount of space left for 20,000 or more bats to leave was no more than a few four-inch squares.
Bats are completely protected from killing, collection, or possession by the New Jersey Endangered and Nongame Species Conservation Act. Because of this and the company's co operative attitude, we were able to have the entrance reopened within two weeks. It was restored to the original configuration which allows bats to pass through the crossed angle irons at the upper portion o the entrance. Although even the old barrier restricted the movement of animals and fresh air, bats were able to leave after hibernation and use the area during the summer as they have for decades.
As a result of this incident, the ENSP and the mine owners have become more knowledgeable about how changes in the shaft affect the bat population. The owner has taken the initiative of contacting outside experts for a new gate design, and work will begin in Spring 1990.
We are all hopeful that the new gate will preserve and enhance the hibernaculum and perhaps increase bat numbers and local use in the next few years. Additional funding from a state income tax check-off for wildlife has made it possible for the ENSP to devote resources to monitoring the site once it is properly gated.
Jo Ann Frier-Murza is the Bureau Chief for the New Jersey Endangered and Nongame Species Program. She is also a member of BCI.
An important hibernation site for little brown bats will soon be protected with a new gate at a New Jersey mine. PHOTO BY MERLIN D. TUTTLE