March/April 2018Spring in the Salkehatchie SwampBy Pete Laurie, Photos by Phillip Jones
In the obscure upper reaches of the Ace Basin, advancing spring triggers a renewal of life in the Salkehatchie Swamp.
In South Carolina's southeast corner, Salkehatchie Swamp extends from Yemassee north to Bamberg on both sides of the Salkehatchie River and the Little Salkehatchie River. These two Coastal Plain rivers join to form the Combahee River, although old timers call any portion of the Combahee north of Yemassee "Salkehatchie."
The Comhahee's tidal influence ends just about where U.S. Highways 17A and 21 cross the river at Yemassee, and from this point upstream the river becomes more swamp than river. Most of Salkehatchie Swamp, which includes portions of five counties and covers thousands of acres of forested wetlands, consists of braided streams rather than a single channel.
During a recent spring, I made a number of trips to this little-known part of South Carolina to observe how the swamp's abundant flora and fauna changed with the advancing season. On most of these outings, I visited private property a little downstream from the confluence of the two Salkehatchies.
A warm, sunny morning offered hints of spring mixed with the last vestiges of winter. Among the earliest spring nesters, barred owls, denizens of southern swamps, called from both sides of the river, here about fifty feet wide in a well-defined channel, and quite muddy after recent showers.
On the adjacent floodplain, towering cypress trees had just started to develop short, pale-green needles. Robins in small flocks called throughout the damp floodplain along the river's edge as they picked through last year's muddy leaves. Flocks of robins typically forage across the winter swamp in search of American holly berries and other delicacies. By March, most robins had left for northern nesting areas, leaving just remnant, nomadic flocks.
Walking upstream along the muddy, undulating substrate where winter rains had recently, but only briefly, pushed the river out of its channel, I came upon several robins hovering at a hole in a hollow stump. On fluttering wings, they took turns briefly hanging in the air to pick off emerging termites gathered at the hole. Surviving termites flew off weakly, their transparent wings gleaming in the spring sunlight.
In the still bare willows across the river, a half dozen rusty blackbirds, a much less common winter bird in the swamp, called to each other with low creaky voices. But in a sure sign of the changing seasons, from across the river came a parula warbler's buzzy, high-pitched song, the first I had heard that spring.
A red-shouldered hawk, soaring above the treetops, called repeatedly as a Palamedes swallowtail butterfly, bright black and yellow, flew among the drab tree trunks. On a sandy spot a mourning cloak butterfly paused in the sun.
Late in the afternoon, I looked in at a wading bird rookery farther upstream in the swamp where great egrets had already built flimsy stick nest platforms on small horizontal limbs of the scattered cypress trees towering above a shallow backwater. On some nests, a single egret stood motionless; others contained a pair of birds, often one standing upright, its mate prone, perhaps brooding eggs.
Among the elegant white egrets, a few darkly-plumaged anhingas occupied similar-looking stick platforms. Larger wood storks, on a later schedule than the egrets, carried sticks to nests still under construction. This busy backwater covered twenty acres or so of tall, well-spaced cypress trees, with nests on every horizontal branch.
With nesting just beginning, the rookery remained quiet and peaceful, despite the many large birds in close proximity. This tranquility abruptly changed an hour before sunset. White ibises began to pour into the backwater from the north and west in groups of five or ten, and then flocks of eighty to a hundred. They soared in above the treetops, then suddenly dove down, twisting and turning like waterfowl pitching into a set of decoys. Some passed close enough to hear the rush of air through their wings.
Wave after wave of ibises poured into the rookery until hundreds of the white birds adorned virtually every available perch at all levels of the tall cypress. The nesting egrets and wood storks took little notice of this flurry of airborne activity which ceased by sunset. A single adult eagle, resplendent in the setting sun, flew the length of the rookery, but high enough to not disturb the wading birds.
On this cool, overcast morning, a sudden breeze dislodged a rain of golden catkins from oak branches overhanging the river creating a ribbon of gold along the meandering river, as it slid and gurgled over and around the tangled blow downs. Along the river's edge, the dark-green foliage of red buckeyes, just beginning to show buds, stood in stark contrast to the pale-green new foliage of the oaks and cypress.
An immature Cooper's hawk on fixed wings shot across the still wintery-looking swamp, just six feet above the muddy substrate, as it searched for a careless robin or yellow-rumped warbler.
The river had risen about three feet but remained comfortably within its banks. In years of heavy rain, the Salkehatchie often overflows its channel, flooding thousands of acres of the adjacent flood plain, but this spring of only occasional showers, the river, at least at this point, generally pursued a single channel.
As treetops continued leaf development, the swamp assumed a greener look, but still not the dark, vibrant green of late spring and summer. Robins, yellow-rumped warblers and other winter birds had vanished, but spring singers, including Carolina wrens, cardinals, yellow-throated warblers and parulas, filled the cool, clear air with competing melodies.
At the wading bird rookery, great egrets incubated eggs on most nests, and some wood stork nests held a single egg. Except for a fish crow's nasal Ah, ha from a cypress top, the rookery remained quiet despite the hundreds of large wading birds in close proximity.
As a preview of the more frantic activity to come, once the eggs hatched and adults began to bring in food, an egret flew in and passed a small, silvery fish to its mate, prone on a nest, then immediately flew off.
A visit to Rivers Bridge State Park near the upper end of Salkehatchie Swamp provided a different sense of this complex wetland. At the battlefield portion of the park, the distinctive melodies of spring singers - pine warblers, tufted titmice, solitary vireos - filled the warm, damp air along the walking trail that skirts the swamp.
Here, as in much of the Salkehatchie, water moves almost as a sheet flow, waist-deep with no discernable channel. Although only about a hundred yards wide at this point, the large cypress trees with their multiple knees, along with fallen branches and tree trunks, made the swamp all but impossible to cross on foot. One can understand how - towards the end of the Civil War - a small band of Confederate soldiers halted the advance of a much larger Union force here for days.
But on a spring morning, the tangled blowdowns and meandering, black water seemed almost inviting, at least to a flock of a dozen white ibis which drifted in to settle in the shallow water among the cypress knees, where they began to probe vigorously for crayfish. The now completely leafed-out cypress sported a few brownish male catkins among the stubby needles, along with round, green balls that by fall would develop into cones.
Hatching mayflies, yellowish with long tails, fluttered from the water's edge to alight on tree trunks and the tips of branches to dry their wings. A pair of wood ducks flew twisting among the cypress and swamp chestnut oak trunks with an enthusiastic, Whoop, whoop, whoop. Overhead, turkey vultures circled on the rising thermals as the morning air warmed.
To observe fish species that inhabit Salkehatchie Swamp in spring, I tagged along this morning with SCDNR fisheries biologist Chris Thomason on one of his redbreast surveys. We launched his boat at a little landing where U.S. Highway 21 crosses the river and headed downstream into the upper Combahee. Upstream from the bridge, Thomason explained, fallen trees block the river for boat traffic all the way to the Salkehatchie headwaters. He blamed widespread logging of the swamp in the 1980s for much of this obstruction. Loggers left narrow bands of trees along the edges of the river and its tributaries. Subsequent storms blew the exposed trees into the water, blocking boats from most of the swamp.
With the gas-powered generator humming, Thomason maneuvered the boat among the overhanging limbs and vines while I stood on the raised front deck, where electrodes dangled into the water on either side of the bow. Stunned fish immediately began to roll at the surface.
During the next hour and a half, I netted six redbreast, missed a few more, and got a feel for the number and diversity of fish in this part of the watershed. Among the briefly stunned, but unharmed fish, we saw many long-nosed gar and largemouth bass, along with white catfish, spotted sucker, a late season American shad and a carp of six or eight pounds. Although striped bass also inhabit the Combahee, Thomason said in the spring they spawn farther downstream, then swim upstream to spend the summer in the cooler, shaded waters of the swamp.
With the river still flowing quietly within its banks, I walked upstream through the frequently flooded edge among tall cypress and oak, the damp substrate littered with last year's fallen leaves and acorns. In an open spot, flower flies buzzed among the blooms of a thick poison ivy vine that had overwhelmed a small sweet gum.
Across the river, a female wood duck splashed at the water's surface, trying to attract my attention as the current swept a raft of eight ducklings around a bend and out of sight. On a shoal on the river's opposite bank, the drooping limbs of black willows, now richly green, hung in the water, swaying with the current.
The constant two-note song of red-eyed vireos filled the morning air. I finally spotted one of these active little birds in a shaft of sunlight on an oak branch, where he paused for a second, alertly looking for insect larvae hidden among the foliage.
From a three-inch diameter hole about fifteen feet up a small cypress came a steady stream of honey bees, while others perched at the edge of the opening, fanning their wings to provide ventilation for the hive.
Just when I thought all the swamp's winter birds had left weeks ago, a very late swamp sparrow jumped from a grassy puddle and flew silently just a few yards before dropping again into cover. Nearby, a blooming native wisteria had climbed into a young sweet gum.
At the rookery, most of the great egret nests now had tiny, fluffy chicks, two or three per nest. Wood storks still patiently sat on eggs.
Despite a morning temperature in the low 50s, spring continued to progress with scarlet tanagers singing from the leafy canopy along the river and prothonotary warblers calling, Sweet, sweet, sweet, from the swaying willows.
The river, up more than a foot after heavy showers, flowed briskly and more clearly than two weeks earlier. In the cool air, a slight mist rose from the warmer surface water. Farther upstream the river had overflowed its channel; sloughs that previously held only standing water now flowed quietly, wandering among the oaks and cypress trunks, often some distance from the main channel of the river. This flow brings in untold numbers of small fishes and invertebrates seeking the nutrients of the river's expansive floodplain.
Spring's green now washed the swamp, a bright transformation from the dull brown look of winter. From far downstream came the plaintive, staccato call of the season's first yellow-billed cuckoo, a spring nester freshly arrived from the tropics. A turkey near the edge of the swamp gobbled explosively.
Mid-morning, a barred owl glided into a sunny treetop, drawing the immediate ire of a pair of blue-gray gnatcatchers that probably had a nest nearby. With flashing wings and tails, the little birds flew repeatedly at the head of the owl, which appeared to take no notice. After a few minutes, the owl, propelled by a couple of quick flaps of its broad wings, glided south along the river, but soon returned to perch on a bare branch. Here, it sat quietly, its dark eyes focused on an isolated slough, looking for a frog or a crayfish.
With the river running almost due south, the rising sun lit up the treetops and understory vegetation on the west side of the river while the east side remained in shadow until a couple of hours after sunrise. Sunlight prompted insect activity, which in turn attracted a variety of birds to these sunny spots. White-eyed vireos and parula warblers searched among the now thick foliage, pausing to sing every ten or fifteen seconds.
I found the barred owl just a few yards from where I had seen it a week earlier, watching the same slough for potential prey. An Acadian flycatcher hovered on beating wings as it picked off small insects from the leafy tip of a live oak branch.
The unusually dry spring continued, dropping the river another foot and exposing more muddy edges populated with dozens of small cypress knees, some many feet from the trunk of the tree, indicating the tree's wide-spreading but shallow root system.
The lower water level also exposed more of the tangle of fallen trees and limbs that clog the entire length of the swamp, making navigation, even with a kayak, all but impossible.
A sudden swirl of water at the mouth of a slough suggested a large fish, perhaps a white catfish. The more regular, quiet "pop" at the water surface I attributed to the abundant red breast.
With spring birds now busy nesting, I watched the yellow flash of a male prothonotary warbler as it flew business-like low among the tree trunks, perhaps on a foraging mission to feed nestlings. Two male parulas chased each other through a thicket of trumpet vine that trailed across an uprooted tree arching across the river.
Heavy thunderstorms, the product of a cold front a few days earlier, had brought the river up almost two feet, again flooding adjacent sloughs. The front also brought an influx of yellow-billed cuckoos. I watched one of the long-tailed migrants in the sunlit canopy across the river, where in short flights it moved from tree to tree, searching for caterpillars, a favorite food. I saw several more of these often-secretive birds during the next few hours and heard them calling throughout the swamp.
Under the willows across the river, a great egret stood motionless in a shallow eddy. Watching the current sweep around its long legs, it suddenly stabbed the surface to capture a small fish, which it swallowed with a quick toss of head and straightening of neck. The bird no doubt had a nest in the rookery just a half dozen miles upriver. Wading birds often travel considerable distances to forage for their nestlings.
A pair of summer tanagers, the male fiery red, its mate a smooth yellowish-green, worked the lower canopy of a shortleaf pine, their large beaks almost yellow in the sun. A ruby-throated hummingbird briefly joined them, probing among the pine limbs, perhaps looking for insects, or spider silk for nest construction.
Within a few hours, the heat of the morning sun reminded me that summer was approaching, and spring's renewal of life had reached completion for another year. As I drove out of the swamp, a swallow-tailed kite floated overhead, buoyant and graceful, as it rode the rising thermals, a fitting finale to spring in Salkehatchie Swamp.