If you are wondering why we would need such an Memorandum of Understanding or you are one of those folks that think all bats are the vampire creatures portrayed in the Dracula movies, consider this. Bracken Cave, near San Antonio, Texas, is the spring roosting site of some 20 million Mexican free-tailed bats. Each bat weighs approximately one ounce and will consume one-half its body weight in insects each night. The mathematical result is that this one colony of bats consumes over 150 tons of insects each night. A much smaller colony living in the Old Orient Mine in Colorado consumes almost 2 tons of insects each night.

In addition to their role as primary predators of a wide variety of insects that cost farmers and foresters billions of dollars, these flying mammals are also instrumental in the pollination and seed dispersal of numerous plant species. For example, Margarita lovers should know that tequila is produced from the agave plant whose seed production drops to 1/3000th of normal without bats as pollinators. Bat droppings (guano) support entire ecosystems of unique organisms, including bacteria which can be used to detoxify waste, improve detergents and produce gasohol.

Contrary to their much-maligned image, bats are ecologically and economically critical to the well being of the nation. And yet, over half of the 43 species living in the U.S. are endangered or on the candidate list for endangered species. As their traditional habitats such as caves and tree hollows are being disturbed by human intrusion, bats are becoming more and more dependent on abandoned mine sites for suitable habitat. Many of the 43 species, including endangered species, have been observed using abandoned mines either as permanent roosts or temporary stops during migration. Abandoned mines provide microclimates similar to caves, suitable for rearing young, hibernation, and rest stops during migration in the spring and fall. Closure of mine openings without a biological survey can trap and destroy an entire colony of bats.

The Office of Surface Mining and the States, through their Abandoned Mine Land programs, are committed to the protection and preservation of bats, their habitat, and their ecosystems. Although procedures may differ from program to program, a biological survey normally is conducted in coordination with wildlife departments to check for bat habitation prior to closure of a mine opening. If bat activity is confirmed, the typical response is to construct a bat gate. Bat gates may be different sizes, shapes, or designs but usually involve a steel grid with openings large enough to allow passage for the bats, yet small enough to prevent human entry. Gates often are installed on mine openings with no visible signs of bat habitation in order to maintain ventilation patterns which may be essential to adjacent or connecting areas which do contain bats.

Over 300 bat gates have been funded and constructed since the commencement of the Abandoned Mine Land program, with the Office of Surface Mining Federal Reclamation Program and the various State programs averaging from 1 to 15 gates per year. Costs range from a few hundred dollars to $18,000, with an average of less than $5,000. One reclamation project in Ohio involved the installation of bat gates over three large mine openings and cost $54,000. The type of gate installed depends on the size of the opening and the species of bat using it. While most species tolerate gates and readily adapt to them, some species do not. For these bats a concrete wall blocking most of the opening is effective so long as a horizontal opening is left at the top of the closure to accommodate the bats. Other type gates may include a lockable gate to provide for future human entry if necessary. Bat gates must meet the primary objective of protecting the public from a hazardous condition and, oddly enough, are often more economical than conventional mine closure methods.

Given that bats rely heavily on abandoned mines for their survival it is imperative that the Office of Surface Mining and the other involved government agencies continue the protection of those mine habitats. Enhanced public awareness will assist in this protective efforts by pointing out the many benefits derived from our bat population and dispelling some of the myths. There is growing evidence that the public is taking a more favorable view of bats. Blueprints are available and many people are building bat houses in their backyards, much the same as you do for wrens and other birds. This Memorandum of Understanding will result in closer collaboration with Bat Conservation International and the saving of more prime bat habitat in abandoned underground mines.

If your interest has been sufficiently tweaked, excellent publications are available. Copies of "Bats: Masters of the Night Sky" are available free of charge from the Bureau of Land Management, Public Affairs, 1849 C Street, N.W., Room 5600, Washington, D.C. 20240 or phone: (202) 208-5717. Copies of "Bats and Mines" are available through Bat Conservation International, P.O. Box 162603, Austin, Texas 78716. Instructions and diagrams for building your own bat house may also be obtained from BCI.