Bats Alive!
September 2, 2014. Like June 1, the first of September always signifies for me a changing of the seasons. It means fall has arrived (even though officially three weeks away) because we always started back to school the day after Labor Day.
The only reminder of fall right now is the numerous brown leaves that have fallen on the boardwalk, and the bare ground of the muck swamp, which has finally dried up after being wet and partially flooded for most of the summer. The weather is summer-time – warm and muggy. A thunderstorm just barely missed the swamp, and I hear sporadic rumbles of thunder off to the northwest.
My eye catches something bright to the left of the boardwalk. The neon red, which glows against the greens and earth tones of the swamp, can only belong to a cardinal flower. It’s a spectacular specimen too, being nearly four-and-a-half feet high. I walk over for a closer look and see footprints next to it, a sign that someone else has enjoyed this flower. I used to see more along the low boardwalk but don’t know if the pigs have rooted them all up or whether people have picked them. The muck swamp provides ideal conditions for this beauty – moist, fertile soil.
Paul Ragan with a cluster of pawpaws ready for eatin’
I am on somewhat of a mission today, that of finding some ripe pawpaws to sample. It’s instructive that I have to walk for nearly a mile past hundreds of plants that were covered in blooms back in March before I find one that has fruit. When I finally find a tree with the light green, cylindrical fruit (botanically speaking, a berry), a good number are still unripe, everything being late this year. I give the tree a few shakes and several ripe ones hit the ground. They are ready to eat when soft to the touch. And what a wonderful taste they have – sweet like a banana, with a hint of citrus. I can only imagine how the Indians must have enjoyed eating them. Too bad there are no boy scouts around. But maybe they don’t sing “where oh where oh where is Susie” anymore. I notice a good many of the pawpaw leaves have holes in them from where bugs (caterpillars?) have been chewing.
On my way back I bump into Susan Loeb, a forest ecologist with the US Forest Service stationed at Clemson, and a seasonal park ranger assisting her. They are doing research on the park’s bat populations and have set up several mist nets in which to catch them. A mist net is like a large fine hair net that, stretched in an opening, path, or corridor between trees, becomes almost invisible to any bat flying by (and during daylight hours, birds).
Dr. Loeb and her graduate students and assistants haves been studying Congaree’s bats for ten years. Their initial research was to determine which bats were present. They found six species: big brown bat, red bat, evening bat, tri-colored bat (formerly known as the Eastern pipistrelle), Southeastern myotis, and Rafinesque’s big-eared bat. In 2006 she and graduate student Jessica Lucas began a study of one particular bat species, the state-endangered Rafinesque’s big-eared bat, Corynorhinus rafinesquii. Today the usual place to find this interesting bat with the oversized ears is under bridges and the darkest corners of old, abandoned buildings. But like chimney swifts and purple martins, big-eared bats roosted and raised their young in large hollow trees before humans started building bridges and dwellings (and along the way cut down most of the large hollow trees).
Rafinesque’s Big-eared Bat.
For the big-eared bat, the maternity-roost tree of choice in Congaree is virgin water tupelo situated within large sloughs and gum ponds that have other large hollow trees. The researchers found, in fact, that the bats frequently switch roost sites, sometimes every two or three days. In doing so, the females carry the one young they have per year with them.
The bat researchers have started research on another Congaree bat of conservation concern, the Southeastern myotis, Myotis austroriparius. Like the big-eared bat, the Southeastern myotis is a non-migratory specialist of forested wetlands. And also like the big-ear, the myotis prefers large hollow tupelo trees. Sometimes, in fact, the two species roost together in the same tree. Unlike big-ears, which use hollow trees with openings in the canopy or upper trunk, the Southeastern myotis will use hollow trees with basal openings at ground level, for both ingress and egress.
About 8:30 PM (official sunset is now 7:45) the researchers have some luck and capture an evening bat, Nycticeius humeralis. It is truly remarkable to see one of these much-maligned creatures up close. The body size of an evening bat is not much bigger than a shrew’s. It has a small head with tiny teeth that appear unable to break human skin (the researchers wear fine leather gloves just in case). The body is dark, almost black. The extended wings are what make bats appear much larger than they really are.
After weighing and measuring, the bat is tagged on the leading edge of the wing at the forearm with a small, light aluminum band, similar to what bird banders use. Bats can be long-lived despite their small size, and ten-year old bats are not uncommon. Some bats are known to live for more than twenty years.
After releasing the bat the biologists remove their latex gloves they are wearing over their thin leather gloves and deposit them in a discard bag. They are also wearing outer clothing which will be sanitized at the end of the night. These precautions are necessary in the light of “white-nose syndrome” which has mysteriously popped up in bat populations throughout the East since 2006, resulting in death for millions. The syndrome is caused by a fungus which often appears as whitish spots on the bat’s nose. Most bats affected are those living in close quarters in caves, at ideal temperatures, 54º to 60º, for the spread of the fungus.
Rain has started falling so the bat researchers have to shut down for the night and hope for better weather tomorrow. When I return again the next evening, they have three nets set up in time for the early bat flight at dusk. Two of the nets are strung over the Sims Trail, a good bat feeding corridor, while the third is a higher net strung in a natural opening in the cypress-tupelo slough at Tupelo Alley.
A little after dark a Seminole bat, Lasiurus seminolis, is captured in one of the low nets at the Sims Trail. It’s about twice the body size of the petite evening bat and has a twelve-inch wing span. The fur is a deep rich brown with frosted tips (several guide books call it “mahogany”). He’s got the right equipment to be a male, and is quite a handsome fellow. This is a new record for the park, which now has a total of seven confirmed bat species.
Seminole bats are a characteristic species of the Deep South. Like most Lasiurus species, they tend to be solitary, and unlike most bats that roost in caves, hollow trees, buildings, and attics, Seminole bats roost and raise their young in Spanish moss, or under clumps of leaves or bark. They are usually associated with pine forests or mixed pine-hardwoods.
After being measured, weighed, and banded, the bat is released to go about his business of catching moths and other flying insects for his supper. It’s a puzzle to me why these extraordinary, fascinating flying mammals are viewed with such skepticism and sometimes dislike and fear by the general public. Their many novel features, unique life histories, and beneficial nature should make them instead objects of respect and admiration. I’m sure their nocturnal habits have something to do with their image problem, along with the usual issues of superstition, fear, and ignorance that go with things we don’t understand. Hopefully, the good work done by these biologists, as well as by educators and conservation organizations, will make people more appreciative of one of nature’s true miracles.
After making several rounds (the nets are checked about every ten minutes so the bat won’t chew its way out) without any more captures, I depart at 10:00 PM, leaving the researchers two more hours of patient waiting and hoping.
The katydid chorus seems to have called it quits for the summer – I only hear one or two calling from the bluff woods as I exit the high boardwalk.
