At least three species have been seen hibernating in Indigo Tunnel: little brown bats; big brown bats and Eastern pipistrelles. But trap surveys in spring and fall suggest there are more. They have snared long-eared bats (on the federal endangered species list), silver-haired bats, Eastern red bats, Northern myotis and a solitary Indiana bat, also federally endangered.
Nature's only flying mammals, bats play important roles in plant pollination, seed dissemination and pest control. One little brown bat can devour 1,000 mosquito-sized bugs an hour, Haskew said. Bats also eat agricultural pests, sparing farmers $1 billion a year in crop losses and insecticide costs.
At Indigo Tunnel, electronic devices record temperature, wind and humidity throughout the tunnel so scientists can map the conditions preferred by each species. An acoustic recorder monitors bat calls at the tunnel's mouth, and radio transmitters glued to a half-dozen silver-haired bats allow the team to track their movements.
On this cold November night, Haskew and lab employee Katie Parsh, 24, wait for bats to fall into their traps at the tunnel's east portal. Jamie Utz, 24, and Risa Wright, 22, work the west end.
In warmer weather they have caught more than 80 bats in a night. But it's cold now, and it's more than an hour before Haskew scoops the first big brown bat from her trap. "She's a girl, pretty young," she says, judging age by bone growth in the bat's translucent wings. The bat chatters angrily, trying valiantly to bite Haskew's gloved hand and wriggle free.
Weighed in a plastic sandwich bag, the bat tips the scale at a fat and healthy 21 grams - less than an ounce. The small-footed myotis typically weigh just 5 grams.
After curling an identifying band around the bat's forearm, Haskew sends it fluttering off into the moonlit woods.
At present, the Western Maryland Rail Trail follows the old railroad bed along the Potomac, roughly paralleling the C&O Canal's dirt and gravel towpath trail.
For cyclists with thin-tired road and racing bikes, the paved trail offers a smooth ride. The towpath's mud, tree roots and narrow tracks are better suited for mountain bikes.
"It gets rough enough you have to walk," said Richard Cushwa, president of the Cumberland Valley Cycling Club.
An extension to Paw Paw, adorned by old tunnels and bridges, would be a scenic and speedy link in the long towpath ride from Georgetown to Cumberland, and from there along the Great Allegheny Passage trail to Pittsburgh.
