First Day of Fall
September 23, 2014. It’s appropriate weather for the first day of fall in the swamp – cool, overcast, and a light-to-moderate northeast wind. I don’t think it made it to 70º the entire day. I’m looking for fall bird migrants this morning on the Kingsnake Trail south of Cedar Creek Bridge. It doesn’t take long before I spot movement in a canopy opening filled with young saplings (mostly pawpaws) and grape vines. The movement comes from several American redstarts flitting in and out of the foliage, constantly spreading their tail feathers with the yellow “windows.” For me this is probably the most characteristic fall migrant in central South Carolina. They are found anywhere this time of year that supports a few hardwoods, including backyards. I’d say about 75% of the redstarts I see are either young birds or adult females (the so-called “yellowstarts”). The adult males with their black-and-orange plumage are one of our most beautiful birds.
There are other migrants using this opening as well – gray catbird, northern waterthrush, black- and-white warbler, and veery. A redstart and Northern parula have a brief confrontation; as expected, the smaller parula looses. It gets me to thinking about the competitive interactions between the local birds here at Congaree and the fall newcomers. Of course by now a certain percentage of the local birds have moved elsewhere farther south and have become interlopers themselves. It highlights the fascinating and not well understood role of habitat use for migrating land birds.
My attention finally turns to a nearby squirrel climbing the trunk of a big sweetgum with a large, green, ball-shaped object in its mouth. The squirrel is mildly annoyed at my presence but finally settles down on a limb not far away and proceeds to devour its morsel, which turns out to be the green, cap-less acorn of a swamp chestnut oak. It is fascinating to watch the squirrel twirl and turn the acorn in its human-like front paws, like corn on the cob, nervously gnawing away the tough outer shell of the acorn, which falls to the ground in pieces. After completely removing the shell, the squirrel departs with his treasure, and I lose him in the foliage.
I bump into the bat biologists coming down Kingsnake Trail with telemetry gear. They have had the good luck to find a large, hollow water tupelo with a Southeastern myotis maternity colony in it (they could actually hear the high-pitched squeaks of the bats from outside the tupelo before they examined the hollow inside) and have outfitted a captured male and female bat with miniature radio transmitters. Tracking the movements of this bat of special concern will provide valuable information on home range size and habitat use.
I wander off trail for a while; it’s now completely overcast at noon and very dark here on the ground floor. Up ahead a large canopy gap allows what little available light there is to reach the ground. The gap is filled with mostly young pawpaws but also a few slender, forty foot chinaberry trees – not a good sign. But even worse is that at least two dozen small chinaberry seedlings are popping up in the light around the bigger trees. I’m a lot more worried, though, about the abundant Chinese privet I have been walking by for the past thirty minutes back on the trail.
Just beyond the canopy gap something red and low to the ground stands out like a beacon. It is not the glowing red of a cardinal flower, but the tightly-clustered red-orange berries of the green dragon, Arisaema dracontium, a close relative of the familiar jack-in-the-pulpit. I suppose the attractive fruits are meant to be dispersed via the gullet of some passing bird or mammal. However, one of my wildflower books notes that green dragon, like jack-in-the-pulpit, contains tiny needlelike crystals of calcium oxalate that if ingested, become embedded in soft tissues causing “intense irritation and a burning sensation.” Now that hurts to think about it.
On the way back home I stop off at the high boardwalk to check on the patch of jewelweed I last saw more than a month ago. It was too early then for blooms and hummingbirds, but now the unusual orange flowers are out in full force. I wait for twenty minutes to watch for hummer activity but see nothing. Although many hummingbirds have already headed south for the winter, they are still good numbers remaining, so I am surprised not to see any at one of their favorite fall nectar plants.
Not too far from the jewelweed I see a gray squirrel foraging on the ground in the damp leaves and debris next to the boardwalk. It is feeding on the fallen seeds (drupes) of swamp tupelo. The squirrel is rather fastidious about which seed it consumes and passes by the green, recently-fallen ones, and even the darker ones that look ripe. Instead it prefers to scratch, and sniff (pass the smell test?), just under the leaf litter to perhaps find seasoned or cured seeds. Occasionally it stops briefly to clean its muzzle of dirt and moisture with a vigorous wipe with its front paws. The swiftness with which the squirrel dispatches the tupelo seed is fascinating to watch. The mouth and paws work in nervous concert together, and pieces of the seed fly off like wood chips from a dull buzz saw.