Using a radio transmitter the size of a shelled pea, John Chenger is studying an endangered bat population that hibernates in an abandoned rail tunnel near the Allegheny Tunnel on the state Turnpike.
On April 17, he and his associates at Bat Conservation and Management of Carlisle joined with Sanders Environmental Inc. Centre Hall to tag 15 Indiana bats as the came out of hibernation.
“We’re trying to figure out where they go,” Chenger explained. “Do they go five miles? Do they go 300 miles? It just isn’t very well understood at this point.”
The study is necessary because human disturbance and habitat loss have led to the Indiana bat being put on the U.S. Fish and Wildlife Service’s endangered species list, Chenger said. The study is being jointly funded by the wind turbine companies Gamesa Energy USA and Airtricity.
Gamesa, which is planning to build 30 turbines along the nearby Allegheny Front, is trying to learn the potential impact a wind farm will have on the growing bat population, Chenger said. Already, the company has canceled a second phase of the Shaffer Mountain Wind Farm because of environmental concerns, he said.
Learning more about the population’s habits could help the company reduce the potential for deaths caused by turbines, he said. The companies could change the turbine’s operational patterns when a population of bats comes into the turbine area. During bat seasons, windmills could be shut down or slowed at certain times of the day or night, he said.
“It’s important they do post-construction monitoring. They need to have some way of predicting when these animals could be killed,” he said.
His group’s study, which has been helped by the cooperation of the Turnpike Commission, Shawnee State Park and the Pennsylvania Game Commission, will be released publicly later this year by the wildlife service.
Standing in the middle of Shawnee State Park in Bedford County on Saturday, some 10 miles from the tunnel where the bats winter, Chenger said his team has managed to keep track of 11 of the 15 bats they tagged a week ago.
At this point in the spring, the bats are clustered in pairs in an area stretching from the park to New Baltimore. The transmitters batteries will last for 25 days and during that time, the study team will check on every bat daily, using trucks, hand held receivers and even planes.
Chenger followed team members Miles Keyhoe and Keith Moore through the woods, homing in on a cluster of three female bats.
Keyhoe and Moore periodically waved their handheld receivers, which look like a divining wand crossed with a television antenna, searching for the tagged bats.
“They love the pastoral area you get near agriculture. Lowlands. Meandering stream valleys, typical of Shawnee Park,” Chenger said.
The females had chose to sleep in shagbark hickory trees, though they often switch trees in order to evade parasites and predators like owls and snakes, he said.
The group arrived at a tree only to find the bats had swapped trees overnight.
“PA 72 was in here yesterday. Eighty-six has moved back in,” Keyhoe said.
The receivers emitted a different tone for each bat, allowing the researchers to identify individual animals.
They have been finding that the bats not only swap nightly roosts more than they expected, but they are extremely selective about what trees they favor. Standing next to PA 72’s new tree, some 150 yards away from the previous day’s place of rest, the group could see two or three nearly identical shagbark hickory trees. None had been chosen for a sleep-over by the cluster.
Much of the female bat’s lifestyle is dominated by the drive to conserve calories, he said. The females need direct sunlight so they expend fewer calories on warming their bodies. They spend those saved calories on rearing a single pup they will give birth to in June.
The effort to is conserve energy is also why the females seek lowlands and stream bed areas that have higher concentrations of insects to feed on, he said. The males, which do not have the energy requirements of the females, have been finding ravine-filled woodland mountainsides to hole up in, he said.
Later this summer the group will set up another count as the population starts to concentrate in larger clusters or super roosts, Chenger said. Those counts will be done by hand by setting up mist nets, some 30 feet tall and 40 feet wide, in suspected bat flyway choke points, he said.
In the fall, the population will shift again, moving back toward the tunnel area for mating, he said. The team will then have to use nets, high-tech microphones to record bat calls inaudible to the human ear and tiny radio transmitters in order to decipher the complete cycle.
Those changing patterns and intensive research techniques are what makes studying bats so interesting, group members said.
“I just like bats. They are perhaps the most complex mammal out there,” Moore said.
By Dan DiPaolo
Daily American 30 North Chief
29 April 2007
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