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By Dave Dadurka
Keep your arms to your sides. Make no sudden movements. Watch out for snakes. And above all else, don’t scream. You are about to enter … the bat trailer.
On The Nature Conservancy’s Disney Wilderness Preserve, a rare species of bat – the southeastern big-eared bat – invaded a long-abandoned trailer. After several years of decline, the colony’s numbers are now creeping back up.
Also known as Rafinesque’s big-eared bat, the species was named for a professor at Transylvania University who was politely called eccentric (some thought him insane). John J. Aubudon considered Rafinesque a brilliant field naturalist – even after, as a visitor in his home, Rafinesque destroyed Audubon’s violin while capturing a bat. No surprise, Rafinesque then documented it as a new species.
Is anybody home?
Giant live oaks stretch their gnarled limbs over the roof of the bat trailer. Moss smothers its roof; holes have yawned everywhere since the ruthless 2004 hurricanes.
I jam my hands in my pockets to keep from flailing my arms. Our guide, Nature Conservancy wildlife biologist Monica Folk, tells us to keep still and avoid disturbing the bats. We have four minutes: Get in and get out!
We climb wobbly cinderblocks and through a gaping hole into the trailer’s stagnant air. Like a twisted funhouse, the walls play tricks on us – what we first think are bats hanging on the walls are actually wasp nests. Don’t step there! The floor may collapse.
My cohort Judy and I furtively shadow Monica into a bedroom and peer into the closet. Dangling upside-down from the wall is a tiny bat, her big ears as long as her body. These bats are unique in that they move their heads while holding their ears still. The ears serve as a “radar dish”, seeming to rotate on the bat’s head.
We spy on our quivering bat with a quick flash of a headlamp, but then she disappears. “Did you see it fly from the room?” Monica asks. We had not.
They came from the forest
Forced from their ancient roosts in large, hollow cypress and tupelo trees by decades of swamp logging, these big-eared bats have claimed the decrepit trailer to raise their brood of aerial bug shredders. Today, bedroom closets are their makeshift home – where mother and young writhe close together, hanging from the side of the wall.
Males are spurned in the maternity colony during spring pupping season. Mother and baby huddle together; an adult male wanting to cuddle might push them tumbling to the floor. A few of the males spend their time in a spiffy new bat condo, built nearby in hopes of luring bats out of the rickety trailer. So far, the ladies haven’t joined them.
Rather than flying in open areas at dusk and picking off unlucky pests in mid-air, these southeastern big-eared bats belong to a group known as “gleaners” that hunt in complete darkness.
“Gleaners strictly use echolocation to find the silhouette of a bug on a plant,” says Monica Folk. “Their large ears can detect a moth or grasshopper on a leaf within a dense shrub. They swoop through the shrub and pick an insect off the leaf while in flight.”
Little-known critters
In 1992, when Folk began surveying The Disney Wilderness Preserve, she heard that the previous owners’ old hunting trailer might house some bats. She was excited to discover what was thought to be the southernmost breeding colony of southeastern big-eared bats, although others have since been found as far south as Fisheating Creek.
A University of Central Florida graduate student, Laura Seckbach Finn, was interning at the preserve and based her thesis work on the colony. Today this is one of the most well-studied populations of the species, but little is known compared to other plant and animal species.
“If you looked through the literature a few years ago, you would have found very little information on this bat’s preferred habitat, its foraging and food habits, or how long it lives,” Monica says. “Much of the information on the species in Florida comes from Laura’s studies at The Disney Wilderness Preserve.”
Gleaning the cube
We continue down the hallway and peer into another room with a desolate baby crib. Whoosh! A blast of air blows past my head; a bat makes its escape. Paper-plate sized piles of guano line the floor, along with remnant heads and wings of bugs discarded before dinner. In a corner, a half dozen bats occupy a square foot of wall.
Clipboard in hand, Monica quickly counts them and looks for bands on the bats’ wings. (Previously captured males wear blue bands, females get yellow.) Listening closely, we hear the bats rustling along the wall. As their anxious chirps grow louder, Monica signals us to get out – quick.
We pick our way into the final bedroom closet. These bats seem less threatened by our presence, gently flapping their relatively large wings as they circle around us. They appear to study us as we sneak away.
The real swamp monsters
Outside, Monica quickly notes her observations. The population has increased slightly from past years. When first discovered, the trailer’s colony numbered more than 50. Today during her monthly monitoring, she counts 15 bats (up from a low of 10) and suggests that others may have returned to roost in the swamp.
Loss of habitat – swamp forest – is the main contributor to the bat’s decline, but the species is also highly sensitive to disturbance. At The Disney Wilderness Preserve, airboats are a constant concern. Folk and Seckbach Finn studied the impact of airboats on this colony by attaching small radio telemetry transmitters to bats and tracking their movements.
The studies showed bats were spooked by airboats along Reedy Creek, and were forced to forage miles away from their roost. This puts them at greater risk of predation and physical stress. Florida’s recent three-year drought has lowered the creek, preventing airboats from making their way to the bats’ foraging lands. But with wetter weather this year, the boats are likely to return. A scary thought!
Returning to our trusty ATV, the team heads back to civilization. We did not scream.
Dave Dadurka was Media Relations Manager for the Florida chapter. No one has seen him recently …
Nature picture credits (top to bottom, left to right): Photo © TNC (trailer); Photo © John C. Abbott/www.abbottnaturephotography.com (Rafinesque's big-eared bat in flight). Photo © TNC (Rafinesque's big-eared bat).
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