Snow in the Swamp
January 4, 2014
I roll into the parking lot at 7:00 AM. There has been a hard freeze this morning, down to around 24º, and I’m hoping for some sun to warm things up, but it’s 100% overcast. Fortunately there is no wind. I walk down the low boardwalk as far as I can go until the high waters of the past ten days have it covered up. The Cedar Creek gauge is reading 6.75 feet. I think the gauge, which went out of commission for a while, then got re-activated, is probably reading at least a foot too low. I turn around and walk back to the high boardwalk and head east. There are lots of hollies in this area, and a fair number still have good crops of berries, but surprisingly few robins are about this morning. Usually with sub-freezing temperatures the red breasts would be in a feeding frenzy.
I watch a squirrel caching acorns that it sifts up out of the thick leaf layer. I like the little flourish they do at the end after burying food – using their front paws to cover and pat leaves over the cache.
Soon I spot two young boars walking my way until they stop almost at the foot of the boardwalk, completely oblivious of my presence. Here they spend the next fifteen minutes chomping down on laurel oak acorns. You can easily hear the pigs crunching the hard mast with their teeth; occasionally they issue a soft grunt that sounds like contentment. I am reminded of that old saying, “even a blind hog gets an acorn every once in a while.” Makes you wonder how many acorns hundreds of pigs with two good eyes must consume in this swamp every day. What were the hunters thinking when they released all these pigs for sport years ago? Surely they must have known that these vacuum cleaners on hooves were going to be taking acorns away from the deer, turkey, and other native wildlife that use this high-fat, nutritious food to get them through the winter?
The very high reproductive potential of feral swine is soon brought home to me when farther back in the swamp I see three sows with a combined litter of twenty-four small piglets! The piglets are mostly light brown with black streakings on the side although a few are jet black like the sows. I see little piglets every month of the year in the Congaree. On good range a wild sow can produce a litter at six months of age and have two litters a year (sometimes even three). Assuming a sow can live five years in the wild and during that time produce two litters a year with six young per litter, and assume that 25% of her offspring will survive to adulthood, then at the end of her five year lifespan, the pig population from that one sow will have increased to 539 animals. The real kicker with feral swine is that throughout their extensive, and rapidly expanding range which now includes forty-one states as far north as Upstate New York and west to California and Oregon, they have few natural enemies since most large, pig-eating predators are either greatly reduced or gone.
Seeing this many piglets is discouraging after the past ten days of flooding since it is one of the few checks on the high population growth of feral swine. No doubt adult pigs can get out of the way of high water, but heavy flooding should drown a lot of young ones. Perhaps one positive benefit of the newly-arrived coyote population will be as a predator of young pigs.
Bird activity has started picking up near the boardwalk around 10:00 – kinglets searching in dead leaves, chickadees foraging on bare limbs, and woodpeckers rapping out chunks of dead wood. It is difficult this time of year, when sound carries much farther through the leafless forest, to get away from the loud rapping of hungry pileated woodpeckers. Hands down the strangest bird I see this morning is a mockingbird, about as out of place in a wooded swamp as a woodpecker in a marsh. It is drinking from a water puddle and presumably thirsty from feeding on holly berries.
Closer to Weston Lake I see several hawthorn trees growing next to the boardwalk. They are easy to overlook in the growing season. Right now however, their beautiful red-orange fruits make them standouts in the bare winter forest. A hermit thrush is trying to take advantage of the berry bounty, but a robin quickly moves in and the thrush moves on.
January 8. I arrive at the Visitor’s Center parking lot at 7:15 AM. I don’t expect to see anyone this early and this cold (20ºF). It’s supposed to warm up today to 40º or so. By midday the Midlands will have experienced nearly forty consecutive hours of below-freezing temperatures. That is unusual in the Deep South, and no doubt hard on a lot of plants.
I sit on a bench on the low boardwalk. Shortly pieces of cypress cones starting dropping on the boardwalk at my feet. I look up and there in the bare canopy of a tall cypress, now lit up by the sun’s rising rays, are two tufted titmice pecking away on cypress cones.
Some red maple twigs are showing red with flower buds soon ready to open. Hard to believe now that with winter barely here we are starting to see signs of spring already.
Near the overlook at Weston’s Lake I watch a male pileated woodpecker banging away near the top of a forty-five foot red maple with a broken top. The big woodpecker is not concerned at my presence and works on the feeding hole for about thirty minutes, keeping his body stationary and moving his head only. Every minute or so he stops pecking and moves his head closer into the hole; I assume he is using his incredibly long tongue to scoop up whatever he is going after, probably black carpenter ants.
While the woodpecker is working over the tree, a squirrel pokes his head up out of the top, looks around, then climbs down the tree, head first of course, but on the other side of the woodpecker. Both ignore each other. I suspect there is a good bit of competition between the two, especially for nesting and roosting cavities. I had a female pileated show up in my yard several years ago, a noteworthy event since I’m almost in the middle of town. She proceeded to excavate a roosting hole in a large dead pine in my neighbor’s back yard. After nearly a week of intermittent work, the cavity was complete, and she started roosting in it. I was excited about this great opportunity to study the roosting behavior of pileated woodpeckers from the comforts of my backyard. Unfortunately, after hearing a racket coming from the tree one day, I found the pileated trying to get into her cavity, which had been usurped by a gray squirrel. The woodpecker would advance and try to enter; then the squirrel would rush out, and she would back off. After a few times of doing this, to no avail, she gave up and flew away to the west. The squirrel however, enjoyed its purloined cavity only briefly as the tree fell a few days later from a strong west wind.
January 15. I arrive at the park at 4:00 this afternoon. Compared to the recent cold weather it’s quite balmy today, with a southerly wind bringing in warm breezes. The swamp is flooded, again, with Cedar Creek reading 10.5 feet. The low boardwalk, even the benches, are under a sheet flow of water. Around the high boardwalk only the big pines have their trunks out of water. There is a good bit of robin feeding activity in the numerous holly trees around the high boardwalk. I suspect at the present rate of consumption, however, that most of the attractive red fruit will be gone by early February.
Robins and holly berries go together in the Congaree. If not for the numerous berries of Ilex opaca, the big thrushes would have a hard time in the winter after the earthworms have burrowed out of reach and when most other fruits and berries have disappeared.
Another bird seen in a holly tree, but not eating the fruit, is the ruby-crowned kinglet. This friendly little tuft of olive-green feathers doesn’t seem to mind human company, and will allow a close approach. I see it occasionally feeding on poison ivy berries, but its main winter diet seems to be insects and other small invertebrates. You don’t think of insects being active in winter, but in some ways I think of winter in the Deep South as a dormant spring. After a warm spell in January, it’s not unusual for a mosquito or two to make their presence known.
Getting back to the kinglet, I see it gobble up what appears to be a small caterpillar and later a small spider. Kinglets specialize as foliage gleaners – searching the undersides of hollies for hidden insects; they also like to forage in little clumps of dried, dead leaves still hanging on to the trees; one of their signature foraging behaviors is hovering at the end of a leafy branch or dried leaf clump and probing with their tiny beak while on the wing.
Farther along the high boardwalk I see an immature white ibis walking on a large log in the flooded forest. I suspect he and his buddies that I saw a couple of weeks ago are looking for other places to hunt since this much water puts a lot of their food out of reach.
I stay around until well after dark to observe the almost full moon rising. It is always thrilling to see this golden globe rising above the swamp forest and shedding its silver beams through the trees. Above and a little to the left is bright Jupiter. Things in the swamp are quiet. Earlier at dusk I heard a barred owl off in the distance and a brown thrasher, almost the last bird to go to bed, along with the cardinal, give its good night churry call.
On the way back on the high boardwalk I hear one of the most bizarre outdoor sounds I’ve ever heard. It is loud, close, hard to describe, and a little hair-raising. I have never heard anything like it in all my years in the outdoors; at first I am not even sure what class of animal made it. The critter did not repeat itself, and I rack my brain on the drive back home to come up with something. Finally, the only thing that could possibly fit is the Northern saw-whet owl, a diminutive owl even smaller than the very abundant screech owl. Fortunately there are examples of lots of different bird calls on the internet, and I find one at Cornell’s site called “autumn vocalizations” that sounds fairly close.
The little saw-whet breeds to the north of us and overwinters in the Upper South, where it is secretive and little observed. If that’s what it is, it would be the first record for the park.
January 17. It is quiet and cold, about 34º, in the swamp this morning at 6:30 AM. The black night has given way to a purple eastern sky, soon to be lit up with the rising sun. The full moon is low in the western sky. The swamp is still flooded, Cedar Creek being 8.8 feet, but water levels have dropped about two feet since day before yesterday.
At 6:50 I hear a pair of wood ducks squealing as they take off from the flooded forest; at 7:00 the crows start calling and showing themselves. Three of them perch in the top of a tall dead pine, preening, perhaps in anticipation of the sun’s soon-to-be warming light.
At 7:10 I hear a Carolina wren calling, shortly followed by a pair of barred owls – one is giving that famous maniacal call that makes you want to run the first time you hear it (and sometimes after you have heard it many times). Another barred owl sounds off farther back in the swamp at 7:20.
By 7:25 the swamp is starting to stir, with Carolina wrens, robins, red-bellied woodpeckers, and yellow-bellied sapsuckers calling. The sapsucker call for me has a plaintive, almost melancholy, sound that takes me back many years to all-day duck hunts at Sparkleberry. In those early afternoon hours, when hardly anything at all was stirring except for a steady, light breeze that had the bare treetops in motion, and a few thin clouds moving across the blue sky, you had the swamp all to yourself, and the only sound present was the lonely, wistful call of a yellow-bellied sapsucker.
Shortly after 7:30 a soft wind stirs the 130-foot pine canopy; down here on the boardwalk, it is still calm. Pileated woodpeckers and tufted titmice have now joined in the “dawn chorus.” At 7:45 the tall pines, along with some of the shorter tupelos, turn a burnished orange from the sun’s angular rays streaming over the horizon. The noisy robins are feasting on holly berries in front of my boardwalk bench. Occasionally I hear some of the falling berries hit the boardwalk.
Several dozen of the hungry birds are moving in and out of the dark green foliage. It looks like every robin for him- or herself in a disorganized feeding effort. Shortly, a few cedar waxwings join in, but the robins don’t seem to mind the extra company. What they do mind is when one of their cousins, a hermit thrush, wants to get in on the action. It is promptly driven off by the much bigger robin.
Most of the canopy is now lit up with the warming sun, which also highlights a pair of white-breasted nuthatches, a Carolina chickadee, and a ruby-crowned kinglet high above. Are they trying to warm up, find food, or both? After about fifteen minutes the robins suddenly move on from their holly berry breakfast. There are still a fair number of berries left.
I continue on down the high boardwalk towards Weston Lake. I see a good number of ruby-crowned kinglets “leaf gleaning” for invertebrate food in the holly trees, many of which grow right by the boardwalk, and the kinglets are quite tolerant of human presence, even at very close quarters.
American holly is one of the most abundant understory trees at Congaree (although I would hardly call a ninety-five foot holly with an eight foot circumference, a former Congaree national champion, an “understory” tree). They grow in two different habitats: the ones around the high and low boardwalks are doing well in the “muck swamp,” with its high water tables and saturated soils, while others are found on ridges, alongside the oaks and sweetgums, in the bottomland hardwood community.
Although the hollies seem to be the primary target for the leaf-gleaning kinglets, there is other foliage available for them in winter. Numerous laurel oaks still support abundant green leaves, and I also see kinglets foraging in switch cane, sometimes only a few inches off the ground. Cane should be an ideal pantry for a small bird searching for an insect meal because nearly all of the stems have dead leaves and floodwater debris lodged in them, a likely shelter for spiders, insects, and other bird food. One kinglet I see working over the cane confirms my hunch, as I watch it snap its tiny bill quickly in succession on a dainty morsel too small to see.
Another kinglet species found in these winter woods is the golden-crown. They are outnumbered by the ruby-crown at least five to one in the Congaree. They spend more time foraging in bare hardwoods than their larger, leaf-gleaning cousins. The golden-crown reminds me of a chickadee, being similar in size, but even smaller, and they like to hang upside down like chickadees do. The ruby-crown, on the other hand, reminds me more of a smallish warbler in its foraging behavior.
There is not much going on at the Weston Lake overlook. I hear and see a pair of pileated woodpeckers pecking away for a meal on the other side of the lake. An Eastern phoebe is working the lake edges for flying insects that have started stirring in the warming sun.
Around 9 AM the wind starts to pick up and bird activity slacks off. Heading back to the parking lot, I see a group of four black lactating sows with a bevy of young pigs, some of which are enjoying a breakfast of warm milk.
January 24. It is cold, 20º, at 8:30 AM. Water levels in the swamp have finally dropped to “normal,” and much of the floodplain is dry again. I’m on the low boardwalk, which has been submerged or partially submerged, for much of the past month. Bird activity is starting to pick up a little, despite the frigid temps. It seems incongruous to hear the cheery call of a Carolina wren sounding through the dead-of-winter woods, and it almost makes me forget the cold.
I watch a female black-and-white warbler foraging on a tree trunk, searching for insects and other invertebrate food it finds ensconced in crevices and cracks. Back in Audubon’s day it was known as the black-and-white creeper, a name more fitting to me than warbler. The black and white, unlike most of its kin, winters regularly in the Carolinas, although not in any large number. It seems as if I see more females and young birds this time of year than males, which have more black streaking on the head.
Another nearby warbler is also doing some creeping of its own along a hardwood trunk, a pine warbler. It’s a well-named bird, being closely associated with that tree, but sometimes in the swamp you see them in hardwoods some distance from the nearest pine.
I spy a few cedar waxwings and robins feeding on the last of the sugarberry crop high in the trees. And nearby, the green catkins of bald cypress are swelling with chlorophyll. At close inspection, the buds on the catkins almost look like clumps of tiny grapes.
In many places the forest floor, due to the scouring action of the recent flooding, looks as clean and bare as if a leaf blower had come through. And scattered throughout are debris piles of “wrack” – leaves, sticks and pieces of wood – deposited by the flood and piled up against logs and downed limbs. These wrack piles are attractive to rooting pigs that go after the assortment of flood-collected acorns, tupelo fruits, earthworms, and other such foods.
By now it has warmed up to 25º and the ruby-crowned kinglets are out in force, leaf gleaning in the hollies and cane. Another cane-gleaner is the yellow-rumped warbler. A few goldfinches have come down from the tree tops to find water along the edges of the sloughs and guts, still frozen over for the most part, but the little finches are able to find enough holes in the ice to relieve their thirst.