Possum on the Half Shell

August 2, 2015.  I decide on another night visit to the park to take advantage of a day-after full moon. Unfortunately, it does not rise until 9:15 and has still not cleared the trees by the time I leave the park thirty minutes after midnight.

I start out on the high boardwalk. A light rain fell earlier in the evening but was not enough to even wet the boardwalk where the canopy overhangs it. The air is thick with humidity.

Shortly after I get on the low boardwalk, I hear faint, clucking, bird-like sounds and look down just in time to see an armadillo tail disappear under the boardwalk. The odd-looking animal, appearing like a cross between a reptile and a possum, shortly emerges and scurries along the ground next to the boardwalk. It’s the latest in a series of exotic fauna that has invaded the park in recent times, starting back in the 1980’s with feral swine, the 1990’s with coyotes, and the early 2000’s with nine-banded armadillos (I don’t count beavers that started showing up in the 1990’s since they once occurred here naturally). Makes me wonder what’s next? They say nutria, a South American rodent similar to the muskrat and introduced to Louisiana in the 1930’s, is heading this way.

I wonder too what impacts the “possum on the half-shell,” as some call the armadillo, will have in the Congaree? They are mostly insectivorous, feeding on ants, termites, beetles, and grubs, as well as other invertebrates such as earthworms, millipedes, centipedes, snails, and slugs, and in floodplains like the Congaree, even crayfish. But they also have a strong generalist streak, and are probably not above feeding opportunistically on ground-nesting bird and turtle eggs, salamanders, small snakes, and skinks and lizards. They will at times feed on plant material such as seeds, berries,  nuts, and even occasionally mushrooms. Their food habits overlap a good bit with feral swine and between the two could be having negative impacts on what I call Congaree’s “log fauna.”

In the modern landscape, armadillos appear to have few natural predators except for automobiles, which kill thousands every year in their now widespread range, a range that goes as far west as Nebraska, and north to Indiana, with expected incursions eventually into Pennsylvania, New York and New Jersey. The one thing that may eventually limit their expansion is the lack of insulation, which makes them vulnerable to cold winters. They don’t hibernate but dig burrows for security and to escape the elements. In the Congaree I often see armadillo burrows in the large mounds of root balls (tip-up mounds) created by fallen trees. Coyotes and bobcats appear to be their only predators in the swamp. Armadillo flesh is consumed by some humans and supposedly tastes like pork (rather than chicken). They are well known for having identical quadruplets and the only other animal besides humans to contract leprosy.

Armadillos are adaptable to a wide variety of habitats and seem well-equipped for floodplain living. They can hold their breath for long periods of time, have been known to cross water bodies by walking on the bottom, and can make themselves buoyant by partially inflating their bodies. And of course floodplains provide an enormous variety and abundance of armadillo foods. However, during floods, armadillos, like many swamp critters, have to tough it out and too much flooding probably results in heavy armadillo mortality.

I stay on the low boardwalk and make my way to Weston Lake. At Tupelo Alley I find another armadillo next to the boardwalk. This one also hurries out of my way and runs off into the now-dry slough that runs into Weston Lake.

A green (bronze) frog, a smaller relative  of the bullfrog and very abundant at Congaree. By John Grego.

I arrive at the lake overlook at 10:30 to a chorus of green frogs (aka bronze frog), if that’s the right term for their monosyllabic, banjo-like calling; katydids and crickets are serving as back-up. I see only a handful of lightning bugs tonight, mostly around the high boardwalk back near the bluff line at the visitor’s center. The still-rising, orange-yellow moon is mostly hidden behind the thick canopy foliage. I sit for nearly an hour without hearing anything else except the occasional splash of a fish and a few, far off, one-note barred owl calls. I listen, in vain, for the faint laughing of the Weston Lake sturgeon rider.

I return via the Sims Trail and high boardwalk. Just before arriving on high ground, the beam of my headlamp picks out a bright green object on the boardwalk handrail. At first glimpse I think it’s a leaf, but a second look shows it to be the caterpillar of a tiger swallowtail butterfly. It’s about an inch-and-a-half long with the characteristic small yellow eye spots near the front of the body. It obviously fell from an overhead leaf, where it was much more camouflaged, and secure, than here on the handrail.