Last Run in the Batmobile

 
Last run in the backseat of the batmobile at Rushton Farm—it’s not what you think. Sarah Deutsch cradles a computer in her lap while Todd Alleger steers the truck around the mown paths of Rushton Farm and preserve in Malvern, Pennsylvania. It’s nearly 11 and the darkness is complete. Inside the batmobile, the computer’s graphed and moving lights widen our pupils and steal all thought. The echolocations are amplified; eerie squeals and chittering clicks fill the truck as we move through a bat feeding area.  

The otherworldly noise is unaccompanied by the bullet-and-cape movement of their corporeal forms; instead, an algorithm of vocalizations appear on the screen. The bats show up in chemical blue tracks. These Nike swoosh makers are big browns, Eptesicus fuscus, the most common of all North American bats. In a resting state, big browns are relatively small: with their wings folded, they’re the size of an inside-out garden glove. Outstretched, wingtip-to-tip, they span a greater length than my two hands linked thumb to thumb. Like a cross section of surf, the waves of their vocalizations sweep across our line of vision.

It takes time to register all that what we see. Big browns are not the only things moving. The bats’ echolocations overlay the algorithms of hundreds of insects swarming the meadow. The flicking vertical lines make it appear that the meadow is simply raining with bugs; an image not far from the truth. Bats orient to their surroundings and prey by emitting high frequency vocal signals and then discerning between the returning echoes of their calls as they bounce off targets. They hunt by ear. Fine-tuned echo-locating enables them to weave through trees at speed—dodging collision by feint and tilt—all the while pursuing their prey.

As a former whipper-in for beagles hunting cottontail in fields like these, I long to watch the bats hunt in real time. I am anxious to step outside the truck and see what I can on this overcast night. I wonder: Do they row the air in zigs and zags? Are they hunting in pairs, calling out to one another in some un-hearable octave? As a whipper-in, your ears become so attuned to hound calls that in time you discern meaning, distinguishing the urgent here-come-here-now call of a hound who has found the line as distinct from lukewarm cry of a babbler. I suspect the bats are drawing the covert that runs across the middle of the meadow. Are they working in unison, driving the insects before them or casting the meadow solo, working alone, yet in company? It may be there’s a “social context” beyond orientation, and they’re calling out: Flying beetles, stink bugs! Here above the milkweed and asters, come on, come!

At night, it’s easier to comprehend the notion that the meadow is comprised of not just earth, but sky. The airy domain sustains bat populations as well as chimney swifts, swallows, whippoorwills, and common night hawks. Lisa Kiziuk, Director of Bird Conservation at Willistown Conservation Trust, first introduced me to the concept of the sky as vast feeding ground. As we peered inside Rushton’s two free-standing chimney towers, built to sustain the declining populations of chimney swifts, Lisa explained that swifts are dependent upon “aerial plankton.” It’s a brilliant image, for many of the airborne insects are not visible to the naked eye and they lack the ability to move against a current. Spider mites—who comprise the majority of the daytime aerials—simply float and drift on air. Some of us might occasionally look up in daylight and think of the unseeable stars overhead. But how often, if ever, have we looked up and considered that the sky might be as alive as the sea, teeming with living organisms, too tiny and vast for the human eye to track?

Contemplation of biological richness and diversity: it’s the reason we have gathered and will meet again at sunrise. Heather Kostick, a first-year University of Pennsylvania Master of Environmental Studies candidate, has organized Rushton Farm and Rushton Woods Preserve’s first ever BioBlitz: an intensive biological survey designed to help account for and map species and habitat. Heather has assembled a team of volunteer scientists and students from University of Pennsylvania, Villanova University, University of Delaware, and Juniata College. Other organizations contributing to the intensive survey of bats, insects, birds, mammals, reptiles, and plants include the Delaware Department of Natural Resources and Environmental Control, both the Pennsylvania and New Jersey master naturalists, and the Pennsylvania Herpetological Society.

The idea behind the survey is to compose a living snapshot of Rushton’s 86 acres of farmland, meadow, wetland, and woods. The alert scrutiny will continue the next day with ornithologists banding birds in the woods and making counts; herpetologists wandering streams and poking around in woodpiles in search of salamanders, frogs, and snakes; water biologists stationed by the bridge, looking for mayflies, dragonfly and damselfly nymphs, and hellgrammites; entomologists will identify insects collected overnight while botanists survey the meadow and woods.

Even in the dark, I know these fields well enough to carry a map of the terrain in my head. Where we are now—on the rim of the meadow bordering Goshen—is where most riders urge their horses on. The footing is good, the path straightforward; it’s the kind of place where you take a deep breath—even with a skittish thoroughbred. That the daytime locus of sunlight and calm should so transform by night is both daunting and thrilling. There are so many “bat-hits” here that Sarah asks Todd to pull over to track the flurry. As we head downhill toward the riparian area—on the way passing the place where three years ago two enormous baby vultures fledged in a scrappy ground nest—our first red bat, Lasiurus borealis, makes an appearance. These silky, red-haired beauties are fast fliers who prefer the habitat of forests, woodland edges, and clearings to urban areas. They tend to fly solo, unless migrating or breeding, each night returning to familiar woods and meadows. Sarah describes the algorithm for their echolocations on the screen as a “hockey sticks,” but to me it seems they move like Greek gods thundering down the diagonal on a shaft of light. Their arrivals transform the woods.

My desire to step outside the truck, to see what I can of the red bat’s arcs and dives, has never been stronger, but running counter to that impulse is the lure of other narratives. These darkened woods are full of master naturalists teaching and telling stories. Down by the stream, another chiropterologist is checking on the bat wand thrust like a spear into the stream bed to measure nocturnal traffic. Lisa Kiziuk’s grad students are telling their best bat stories. Herpetologists are flipping rocks as they trace the glinting channels flickering under their head lamps. Back at the herb garden, Adam Mitchell, a 6’4” entomologist from the University of Delaware clad in cowboy boots and a Stetson hat, has gathered a following. He and a colleague are burying Dixie cups flush with the ground so as to trap and catalogue the drop-by insect population. He’s talking about the nocturnal black ground beetle he expects to find tomorrow morning in the organically farmed Rushton fields—bellwether for healthy gardens. Beyond the farm shed, bright nylon tents are shooting up support poles like spinnakers; scientists, grad students, and volunteers are laying out their gear for tomorrow’s sunrise start. Everywhere there’s a thrum of voices, islands of activity. The farm fields feel as alluring as a rural bluegrass festival by night.

Up by the farm shed, a lamp-lit bed sheet suspended like a spider web is drawing in moths. It’s hard not to stare. Some are splendid, others look like your average back-porch nondescripts until you stand alongside the naturalists, leaning in for a second or third look, marveling at a violet furze or subtle fringe. There’s talk of Muir, Thoreau, and Darwin, and then the Judas goat on the Galapagos islands—a spayed female brought in to lure and cull the invasive goat population. In the midst of these narratives, the tulip tree beauty alights. Crowned ripples spill outward from her thorax; her mottling is such a perfect blend of hues that even in full daylight if she flitted off to the border of trees along Delchester, she’d disappear as completely as Daphne, legs and arms slipping into beautifully patterned sleeves of bark.

Almost out of hearing, Alison Fetterman’s late night owl walk is in progress. One of her crew is mimicking a variety of owl calls and succeeds in drawing in a screech. If you have ever once heard the lonely, wavering tremulo of a screech owl, you will never forget the haunting and beautiful summons. The cadence is arresting. The Eastern screech owl makes a series of calls, then pauses. You hear it once and it’s gone. You wait for it to recur, think you’ll never hear it again, not in a lifetime. But then the call begins and there’s time for the exquisite beauty to imprint head and heart.

No one wants to leave, and many won’t; but it’s time for me to go. The familiar world has grown rich and strange. As I head to my car, I make one last loop of the upper fields, thinking about the bats drawing their coverts and the laden quiet between the screech owl’s call. Night after night, bats, moths, beetles, and spider-mites make their way, some directing their paths, others simply riding the wind. Cued by the season, temperature, and a good wind, birds and owls might begin or continue their mass migrations to summer breeding grounds. Ground beetles in their armored carapaces scuttle along the cutting garden’s first row of zinnias, milksnakes burrow into the northern end of the burn pile, scratching loose their waxy skins. Knowledge of their company is comforting as the June weave of cicada and cricket thickening with the onset of summer. Abundance is the word that repeats like a refrain.