OCTOBER 2000 V.64, N. 10 

      Night has fallen like a silken black cape draped over the still green hills of planet Earth. On a remote hillside, beneath an umbrella of oak and redbud boughs, a lone man crouches in silence. Staring intently into the mouth of a cold dark cave, its chill air wafting out to numb his fingers, he waits for the emergence of winged life forms he knows lurk inside. Only his face, illuminated by the pale, ghostly green glow of his night vision scope, is visible in the darkness. Like a cat eyeing an unsuspecting mouse, he sits motionless, peers steadily into the depths of the cave, and waits.

      The scene might be something out of a sci-fi film, did the glowing green face not belong to Division of Natural Resources' (DNR) endangered species program coordinator Craig Stihler, better known to some as West Virginia's own "bat man." On this night in early June, he is counting endangered Virginia big-eared bats as they emerge from a Pendleton County cave to forage for insects, mostly moths.

      In reality, Stihler is not alone. Some 60 feet above him, endangered species program biologist Jack Wallace perches on a limestone cliff. Tethered securely to a red cedar tree by a long nylon strap, he leans forward, watching a second, higher entrance to the cave through futuristic-looking night vision goggles. The goggles allow him to count bats hands-free, so he can record the numbers exiting the cave by whispering counts at regular intervals into a hand-held tape recorder.

      Sitting below, his night vision scope secured to a tripod, Stihler uses the same counting method. Before getting into counting position, Stihler and Wallace have placed several battery-operated spotlights, covered with infrared filters, at both cave entrances. Shining through these filters, the lights are invisible to both humans and bats. Yet, seen through night vision equipment, they light the cave entrance brightly with an eerie glow that makes the bats easily visible as they fly out.

      Tonight's cave is but one of 11 that Stihler, Wallace, and Down For the Count and Natural Heritage Program biologist Russ McClain will census back-to-back in a two-week marathon to determine the number of female Virginia big-eared bats living in maternity colonies in Pendleton, Grant, and Tucker county caves. The timing for the summer census is critical. It must be undertaken after the females have chosen the cave in which they will raise their young, but before they have actually given birth. After the bats give birth, there may be no time when all of the adults exit the cave at the same time.

      A subspecies of the Townsend's big-eared bat, the Virginia big-eared bat is listed as federally endangered by the US Fish and Wildlife Service. With a total population of approximately 20,000 individuals, this bat is found only in Kentucky, North Carolina, Virginia, and West Virginia. More Virginia big-eared bats live in West Virginia than in any of the other states. One cave in West Virginia harbors more than 6,350 of these bats during their winter hibernation, the largest concentration occurring anywhere.

      While the caves visited for the summer census house a variety of West Virginia's 14 bat species in winter, by late spring most of them have left to spend the warmer months in the woods or in buildings in residential areas. It is largely the female Virginia big-eared bat, which raises its young in caves, that remains.

      These maternity colonies often gather in small domes in cave ceilings where the bats' body heat is trapped, creating a pocket of warm air. Where most Virginia big-eared males go during the summer is unknown, though a few "bachelor" colonies have been found.

      Each female has a single young, known as a "pup," which is born hairless and with its eyes closed. The pups are quite large, weighing as much as 25 percent of the mother's weight. They grow rapidly and are capable of flight by the time they are three weeks old. By six weeks of age they are weaned.

      The number of Virginia big-eared bats declined sharply from the 1950s to the early 1980s, largely due to human disturbance of cave roosts. Particularly sensitive to disturbance, this bat is easily awakened from hibernation. Arousing bats from their winter sleep causes them to use limited fat stores more quickly than normal. As no insects are available in winter, they may starve. In summer, cave disturbances can cause females to abandon roosts or panic and drop their young to the cave floor, where they cannot be retrieved and die.

      Virginia big-eared bat populations have increased since the 1980sÐin some caves as much as 350 percent from 1983 to 1995Ðlargely as a result of the protection of cave roosts. Some critical caves have been closed to human travel year-round. Gates and fences have been built at some cave entrances by the DNR, the U.S. Fish and Wildlife Service, the U.S. Forest Service, and the American Cave Conservation Association. The support of private landowners also has been essential to the protection of many caves. Yet, even with steel bars and bright yellow warning signs that advise spelunkers of the presence of an endangered species, as well as a sizeable fine for trespassing, the gates are occasionally vandalized and bypassed.

      However, with protective barriers in place, the overall Virginia big-eared bat population has remained fairly stable for the last several years. Surveys also are conducted at important caves in winter to count numbers of male and female hibernating bats.

      In addition to summer and winter cave censuses, the endangered species program conducts Virginia big-eared bat foraging studies, during which bats are trapped and tagged with radio transmitters. This equipment allows biologists to track the bats' whereabouts over the course of a night and discover how far they travel to forage. The studies have shown that the bats travel up to 6.5 miles from the cave to feed and roost.

      "New technology is allowing us to answer questions we couldn't answer before," Stihler says. "Until recently, we could only guess how large an area around the cave the bats use. Seeing that they use open areas such as hay fields to forage has changed our view of their habitat."

      This night the bats are a bit slow to begin their exit to the surrounding forest. Watching in an out-of-the-way spot through another scope, I see a few of them begin to swoop and dive, like fluttering aerial acrobats, inside the gate. Looking like soft gray stunt pilots, they approach the gate, circle around, then flutter back inside. Some circle on the inside of the cave and approach the gate again. One or two appear to exit fleetingly, then reenter the cave. Soon multiple bats mingle with each other, and I can no longer tell which ones are coming and which are going.

      With more than12 years experience each in bat counting, Stihler and Wallace can tell the difference. With eyes never straying from the scope, Stihler waits until he is sure he has seen five bats exit the cave.

      "Five bats out," he says as unobtrusively as possible, so as not to disturb the bats routine. And then, "Five bats out. Five bats out." Later the tapes will be transcribed onto a bat count sheet, where the number of bats to exit the cave during each five-minute interval will be calculated.

      Soon the bats begin to leave the cave at an increasing rate. Closing my eyes for a moment, I hear intermittent flapping as fast-exiting bats collide briefly, like winged bumper cars, on their way to the woods. Like mercury in a thermometer, a giddiness rises in my chest as I feel the airy wake of bat wings just above my head and then a burst of breeze against my cheek. I hear Stihler softly uttering his counts with increasing frequency. "Five bats out," he speaks in low tones. And then just seconds later, "Five bats out, five bats out, five bats out."

      The stream of bats rises to a high of 58 in five minutes from the lower cave entrance and 66 in five minutes from the upper entrance.

      After an intense period of exit that lasts about 40 minutes, the numbers begin to taper off until no bats are seen exiting the upper entrance and only three are seen leaving the lower entrance. At 10:50 p.m., after just over two hours of counting, Stihler calls an official end to the night's count.

      Later, back at the Elkins DNR office in the wee hours of the morning, Stihler and Wallace record the exit of 890 bats from the cave: 434 from the upper entrance and 456 from the lower entrance. This figure represents an increase of 40 bats over last year's count at this cave. They note the phase of the moon, weather conditions, temperature, and the presence of other wildlife observed. Wallace records a visit by a woodrat at his upper perch. Unlike one earlier count, when he was unable to divert his glance from the scope while a curious woodrat crawled up his pant leg, Stihler this time notes only the presence of American toads and songbirds.

      Their assignment completed, the intrepid band packs up spotlights, battery packs, scopes, cameras, and tripods. With headlamps penetrating the darkness, they scale the imposing hillside, bound for their waiting vehicles. The thump of doors and whoosh of ignitions signal their departure. A toad chorus trills a song as the group disappears into the night.