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Making a place for bats Stream restoration expands to include consideration of wildlife Monday, May 14, 2001 By Don Hopey, Post-Gazette Staff Writer
It's time to switch on the old bat-light and shine a bat-signal into the night sky over northern Batler, er Butler, County.
The Slippery Rock Watershed Coalition has just put the finishing touches on the first man-made bat hibernaculum east of the Mississippi River and is awaiting the arrival of nature's most misunderstood creatures and the only mammals capable of flight.
The hibernaculum was designed to provide a cool, dark place for bats to sleep during the day and hibernate in the winter. It was a late addition to the Goff Station stream restoration and acid mine drainage treatment project on Murrin Run near the headwaters of Slippery Rock Creek.
While comic book hero Bruce Wayne's subterranean digs on the outskirts of Gotham City are undoubtedly plusher and more high-tech, the Watershed Coalition's new bat cave -- constructed from 60 feet of culvert pipe and a recycled 10-foot tall sewer manhole -- should eventually make a fine hangout for up to 5,000 bats.
"We have built it. Now the question is, Will they come? We feel they will," said Will Taylor, a coalition member and program coordinator at the state Department of Conservation and Natural Resources' Jennings Environmental Education Center.
Nine species of bats are found in Pennsylvania, although four of those are extremely rare. All nine belong to the family Vespertilionidae, also known as evening bats. All are insect eaters, often taking their prey on the wing and often dining over water.
On a good summer night a bat will consume up to 25 percent of its body weight and up to 1,000 insects in an hour.
After feeding through the evening, night and early morning, they roost, alone or in small or large groups, depending on the species, in dark, secluded spots such as caves, hollow trees, rock crevices or abandoned mines. They can also congregate in church steeples, vacant buildings, barns and attics, or under bridges.
"We know that this site is generally good bat habitat with open water near by, some forested area and fields," Taylor said. "There will also be wetlands with lots of aquatic insects, so the setting should be ideal."
Dwindling prey and habitats
Bats -- the only major predator of night-flying insect pests like June bugs, cucumber beetles, leaf hoppers, tent caterpillar moths and mosquitoes -- need all the help they can get.
Common name: Indiana bat
Common name: Red bat
Common name: Big Brown bat
Common name: Eastern Pipistrelle
Common name: Hoary bat
Common name: Silver-haired bat
Common name: Small-Footed bat
Common name: Northern Long-Eared bat
Common name: Little Brown bat
Source: Wild Resource
Their populations are in decline across the United States and worldwide. Of the 45 species found in the U.S., six are federally endangered or threatened, and another 20 are listed as species of special concern by the U.S. Fish and Wildlife Service.
Some bat populations have dropped because pesticides have reduced or eliminated the supply of tasty insects. But the main reason is loss of habitat due to suburban sprawl, development, timbering and mine reclamation that fills in or blocks their entrance to underground voids favored for winter hibernation and summer roosts.
A recent study by the federal Office of Surface Mining found that of the 32,000 mine openings closed by local, state or federal agencies, 1,630 -- just 5 percent -- were done in a bat-friendly manner, using gates or closures that keep people out for safety reasons but allow bats free access.
Sheryl Ducummon, bats and mines director for Bats Conservation International in Tucson, Ariz., said an educational program started in 1993 has been successful in educating public officials and mining companies. Many state abandoned mine closure programs now require that bat surveys be done before a mine is closed.
"There's still work to be done but the awareness is out there now. There are more people understanding the value of bats and the need to help preserve their accommodations," Ducummon said. "And the costs of closing mines in a bat-friendly way are comparable, so it's a conservation project that mining companies, states and watershed groups can tackle."
An expanded reclamation
Although the Slippery Rock Watershed Coalition has completed 11 other surface mine reclamation and treatment projects in the Slippery Rock Creek watershed since it formed in 1995, Goff Station is the first to provide a haven for bats.
"It's an outgrowth of the project and an indication how the group is evolving with new ideas as it grows," said Margaret Dunn, a coalition leader and president of the nonprofit Stream Restoration Inc. "I was just trying to get the metals out of the mine water when the question came up 'What about the wildlife?' "
Raising that question was Bob Beran, coalition member, wetland ecologist and owner of the wetland construction firm AquaScape. He contacted the Pennsylvania Game Commission's Wildlife Diversity Section for design help, arranged for the donation of materials and supervised installation.
"Providing wildlife habitat is one of the things that should naturally be a part of any mine restoration project," Beran said. "On other projects we've included bat, kestrel and bluebird boxes. It's a multiple use management approach to stream restoration."
The manhole chamber was dug into the ground at the bottom of a natural slope to take advantage of cooler air circulation, and over the entrance to a long-abandoned deep mine that had collapsed. Drainage from the mine had been coming out of the entrance and the seep has been allowed to continue flowing through the bottom of the chamber because bats are attracted to the sound of running water.
The 60-foot-long, vented culvert pipe was buried at a 30-degree angle, sloping from the entrance down to the chamber, to facilitate the collection and flow of cool air -- another element that attracts bats. The tunnel and manhole are lined with plastic industrial netting designed for use as a landfill liner.
Beran said the coalition's hibernaculum project took advantage of donated materials, but other watershed groups doing stream restoration and mine reclamation projects could easily and inexpensively adapt the model to their area's needs.
Only the gated tunnel entrance, the five tunnel vents and a padlocked trap door that will allow researchers and students to enter the top of the main chamber, are visible above ground.
"The research potential for this project is incredible. The design will allow observation, and vents will allow us to play with the temperature inside the main chamber and tunnel," Taylor said.
"Our hope is that maternity colonies will live throughout the summer in the area and, once new bats are born, they will start scanning the area, scoping for air currents and low temperatures, and looking for new nesting and hibernating sites."
Pennsylvania has had an active bat research and management program in the Game Commission's Bureau of Wildlife Management since 1980, and has cataloged more than 1,000 caves and 4,122 abandoned coal and limestone mines as potential bat roosting locations.
Each winter the Game Commission enlists volunteers to survey some of the mines and caves to determine if bats are living in them. An old limestone mine at Canoe Creek State Park in Blair County was found to contain more than 20,000 bats and six different bat species.
"A lot of the mines are potential safety hazards, and the state has been closing them on a priority basis. When there's an indication that bats are present, we're called in to do a survey," said Jerry Hassinger, supervisor of the commission's Wildlife Diversity Section in the Bureau of Wildlife Management.
"We hit a lot of dead ends, but in the summer, if we can feel cool air blowing out, it's a 'breathing mine,' and there's a good chance there's bats in it."
About two dozen deep mines in the state have been closed using bat-friendly doors or grates to exclude humans. Hassinger also works with property owners who discover bats in their homes or barns and want to get rid of them.
"If it's a big colony we'll provide alternative housing by building what we call a 'bat condo' nearby," he said. "They're like giant bat boxes, 8 feet tall, 8 feet wide and 8 feet deep."
Two condos have been built: at Canoe Creek State Park -- a bat hotspot -- and on an island in the Susquehanna River. Each houses more than 1,000 bats.
Hassinger said another ongoing project involves the recent opening of a sinkhole that leads to an underground cave, again near Canoe Creek State Park.
"There's a 1,000-foot-long passage that leads to an underground chamber where bats hibernate," he said. "We're going to try to put a cage over the top of the hole, and we're trying to do it in a way that will set an example."
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