These scientists love bats because they're elusive and beneficial, and because--as Tim Carter, a mammalogist at Southern Illinois University, says--"They're just so cute." Or because they're just so amazing, in the way Mary Kay Clark, former curator of mammals at the North Carolina Museum of Natural Sciences in Raleigh, describes a column of bats emerging from an Austin cave like a cyclone, their wings making a breeze of the still, humid air.
We were at Bat Blitz 2004, a survey last August of the bat species in the Uwharrie Mountains and the Pee Dee National Wildlife Refuge in Western North Carolina. Researchers traveled from as far away as New Mexico and California to conduct the first scientific count in the area. Bats are the major pollinator in deserts, the major seed distributor in tropical rain forests, and the major consumer of insects that are agricultural pests, yet very little is known about them or why their numbers worldwide are declining.
The routine every night of the blitz was this: Join one of several teams that head out before sunset to sites deep in the woods. Set up a mist net over a stream or across a trail. Sit in lawn chairs in the dark for hours, chatting about bats, telling tales or deconstructing Buffy the Vampire Slayer. Check the net every 20 minutes to see if a bat has entangled itself. If there is such a bat, extract it from the net. Under a bright light, identify the species and take hair, feces and skin samples. Release the bat, recording its call as it flies away. On the long drive home, become giddy with exhaustion until just about anything is extremely funny. Arrive at base camp at three in the morning, in time to join the rest of the teams in a beer around the campfire.
On the shores of Badin Lake, Tim Carter's team set up their mist nets on the paths down to the water. The nets are invisible, especially in the failing light, and at least one of us manages to run into one. I quickly learn to scan the sides of a path for the telltale aluminum poles that indicate there might be something strung between them.
Out on the dock at the edge of the water, a bat detector is picking up calls far above our range of hearing and dumbing them down enough for our ears. The translated chirps indicate hordes of bats flying above our heads. We can sometimes glimpse a winged silhouette against the moonlit sky. Bats are the opera singers of the animal kingdom; their calls cover an enormous range of frequencies. Each signal bounces back from any object it encounters, and from this information the bat can detect the details of the object, even down to the kind of insect.
Joe Szewczak, from Humboldt State University in Arcata, Calif., has written a computer program called SonoBat to render the bat detector's noises into the crescents of red and blue light that he's displaying tonight on a laptop. A flurry of many calls looks like a meteor shower cascading across the black screen. From the images, Szewczak can identify the calls of pipistrelles, bats so small that they can be confused with moths. Within the range of our hearing, a screech owl trills from the woods. The moonlight is so bright I imagine I can feel the heat of it.
The next night I traveled with Mae Lee Hafer, who is the forest wildlife biologist for the National Forests in North Carolina. We headed out to the Thornburg Farm, 150 acres of farmland, house and outbuildings that have been left to the care of the Uwharrie National Forest.
We bounce in the U.S. Forest Service truck through chest-high grass to the shores of a creek. Bats are drawn to streams because they look for unobstructed flyways, because they can catch insects there and because they can drink the water. They live in forests, where they can roost in the trees. When looking for bats, one must think like a bat: Where is the best place to fly? Where is the best place to get water? Where is the best place to sleep? One learns to see the world as a different set of opportunities and obstructions.
The water in the creek is high, turbulent and brown, which doesn't bode well for bat visitations. We spot a calmer place by the opposite shore that is bounded by overhanging trees. Hafer and her team don giant rubber waders that make them look like clowns in baggy pants as they ford the river and set up a net on the other side.
It's a slow night. We catch a single bat that chews on Hafer's gloved thumb like a nursing baby. After we release the bat and dismantle the nets, we search the old farmyard buildings, craning our headlamps into dark corners next to barn rafters, briefly mistaking wasps' nests for bats clinging to the eaves. Curtains still hang in the windows of the abandoned house.
The following night, in the Pee Dee National Wildlife Refuge, I joined the team of Alison Sherman, who's the field biologist/bat coordinator at the Mississippi Museum of Natural Science in Jackson. We've been assigned a bad spot, an algae-covered pool way back in the woods that no sensible bat would ever go near. We decide to drive up the road a ways to a little pond in the midst of fields. The team sets up a V-shaped net just above the water. A bat flies into the net before it's even raised all the way. While the team is working up that bat, four more are caught in the net. The rest of the night is like that; we catch so many bats that there's no time to sit around and gossip.
The fields are loud with the chorus of multiple species of frogs. A tree frog lands on a team member's pants and clings to the material with its little toe pads. Insects fly into our faces, buzz down our shirts. Mist rises from the pond; it's hard to make out the bat inspectors at the net from where we stand on the road 20 yards away.
Close to midnight, I work up my first bat. Contrary to popular opinion, the incidence of rabies among bats is low--one half of one percent of bats tested. However, because we are handling wild animals, we've all had our pre-exposure rabies vaccinations and are wearing gloves. We have the permits required to capture and release bats.
The bat flutters in my hands like a moth. Its fur is the color of a red fox; its wings are slate grey and smooth. Its angry little mouth gapes and chatters. Bats aren't scared when they're caught; they're pissed. I'm terrified of crushing it.
First, we determine the sex. Male bats are studly little creatures; if it's not obvious it's a boy, then it's a girl. The species is identified; like all of the 11 bats encountered this evening, it's an eastern red bat, Lasiurus borealis. Also recorded are the height at which the bat encountered the net and the direction from which it flew. Wing measurements are taken. Specimens of hair, wing and turd are popped into tiny specimen vials and numbered according to bat. The wing specimen is a tiny circle of each wing. From watching the others work up their bats, I've figured out that using the wing punch is like cutting dough to make biscuits: be firm, turn the punch 360 degrees, produce a little black disc of latex-like skin. The hole in the wing will heal in two to three days.
The eastern red bat is supremely adapted to its environment. It sleeps by hanging onto the end of a branch and resembling a dried leaf or by concealing itself beneath litter of the forest floor. It mates in flight in late summer and stores the sperm until the following spring when it bears up to four pups, outdistancing other bat species' average of one per year.
We release my bat. It looks much larger on the wing than in my hands. The spotlight follows it up in the ever-widening spirals until it vanishes into the mist.
All told, seven species were discovered during Bat Blitz: eastern red bats, evening bats, Seminole bats, big brown bats, eastern pipistrelle bats, Brazilian free-tailed bats and the southeastern myotis. There is still so much we don't know--about their sophisticated social systems, about how they communicate with each other, about how they teach their young. There is still so much to discover on future forays into the forests of the night.
Some of the bat species in North Carolina are: