This week for Flora and Fauna Friday we have the companion of cows, the Cattle Egret (Bubulcus ibis).
Cattle Egrets are a small, stocky egret with snow-white plumage, greenish-black legs, and a sunflower-yellow bill. In their summer breeding season they don a blonde mullet with matching bib and back. They are rarely seen alone and typically travel in flocks of one to two dozen birds. Cattle Egrets are common in flooded lawns and fields, near ephemeral wetlands, and roosting over ponds but they’re most often spotted between the knees of Cows and Horses in our sea island pastures. Wiggling their neck as they stalk through the grass and spearing the spiders, grasshoppers, and frogs scared up by the hooves of their neighbors. This is an example of a symbiotic relationship. The Egrets are protected from predators like Foxes and Bobcats by sticking close to their beefy buddies. The Cattle worry less about predators themselves as the keen eyes of the Egrets more surely alert them to threats. The trouble is, there weren’t cattle in the Americas until the 1600s. Neither were there Cattle Egrets.
Cattle Egrets are a curious case of a species’ self-made transoceanic range expansion. One that happened in modern history at that. Cattle Egrets are native to Africa. There they live in the savannas and marshlands amongst the Wildebeest, Zebra, Buffalo, and Antelope. Feeding between their feet and alerting them to the toothier mammals. In the 1870s, by chance, a few flocks of Cattle Egrets flew their way to Suriname in South America. Maybe they were swept there by a hurricane or maybe they hitched a ride on the trade winds. No one knows. By the 1940s they began showing up in the United States. Now they’re the most common Egret in North America. Surely a bird as numerous as the Cattle Egret would have found its way across the Atlantic before, no? Likely they did. Likely not once but dozens of times in the past. But before, there was nowhere for them to live. Colonization changed that and when the Cattle Egrets immigrated to South America in the Victorian era, they found Cows. Lots of Cows all over the place. From there it was just a hop, skip, and a jump to the pastures of the United States. Now the Cattle Egret is ubiquitous across the hemisphere. Here they fill the same niche they did back home. A new niche recreated by man a long way from home.
This week for Flora and Fauna Friday we have a purple plant of our marshy thickets, Swamp Loosestrife (Decodon verticillatus).
Swamp loosestrife is an herbaceous wetland shrub found throughout slow-moving freshwater marshes. This shrub can grow eight feet high in the saturated soils of our marshes. Simple, narrow leaves ladder opposite along the stem up from the muck before slipping back down. It’s slender arching branches tip-toe their way over the surface of the water, dangling down into the mud where they take root. This is an example of a plant that can spread by layering. Although Swamp Loosestrife typically dies back in winter before it can layer, it will do so if the conditions are right. Layering is the process by which a plant’s stem will produce roots when in contact with the soil. This process is quite common in vines and creeping plants but is not so often observed in trees or shrubs. Our loosestrife is an exception.
In late summer, Swamp Loosestrife puts on its grand display. Wrinkled magenta blossoms push their way through the nodes of the plant creating a network of floral chains as if a purple cast-net was thrown over the marsh. Yet, these petals are just the stage for the show. Swamp Loosestrife is an excellent nectar plant and with its blooms it brings forth butterflies. Palamedes Swallowtails, Long-tailed Skippers, Eastern Tiger Swallowtails, Silver-spotted Skippers, Cloudless Sulphurs, Clouded Skippers, Common Buckeyes, early Ocola Skippers, and a myriad more blanket the thicket, ensnared by the web of nectar. The fog of butterflies our loosestrife ushers in can be suffocating when the environmental conditions are right. The blooms attract not just butterflies but droves of bees, wasps, flies, and moths to boot. The flowers funnel in thousands of nearby pollinators per acre for this annual festival and toast to the muck of the marsh.
This week for Flora and Fauna Friday we have a flying hot pink insect, the Roseate Skimmer (Orthemis ferruginia).
The Roseate Skimmer is a member of the Skimmer dragonflies, our most common family of Odonates. Like most Skimmers, it’s partial to open areas above and surrounding bodies of water. Roseate Skimmers are most common in disturbed areas surrounding stagnant waterways. They show some preference for brackish systems and are especially numerous near unkempt retention ponds. Males are territorial and aggressive towards other dragonflies. They’re routinely seen incessantly flying the perimeter of their territory, darting back and forth across a stretch of pond, over and over, day in and day out.
Roseate Skimmers are about three inches in length. Both sexes have clear wings with dark stigmata. Females present a thorax striped with warm browns and creamy whites before an abdomen of a burnt orange-gold. Males are the showstoppers, flaunting a deep purple thorax above an abdomen almost glowing magenta. They are truly double-take worthy creature the first time you spot one. A sudden spark of violet catches the eye and, before you know it, you’re craning you neck and throwing your head trying to chase a sight of a pink sprite between the reeds. Although average in almost all other aspects, the Roseate Skimmer maintains a ubiquitous attraction in all us naturalists. It sits within the ranks of an exclusive group of unignorable items in our natural world. Critters that make us stop and appreciate the beauty of nature, no matter who we are.
This week for Flora and Fauna Friday we have a palatable plant found in forests and fields, American Groundnut (Apios americana).
American Groundnut is a species of plant in the legume family. It’s a low growing vine that’s often found on the edges of moist fields and woodlots. It climbs by twining up grasses, shrubs, and herbaceous plants, sending out a pinnately compound leaf every few inches. The vines are thin and wiry, dying back to the roots each year. Its mauve-pink flowers clearly fit within its leguminous lineage and are presented in dense cones, spiraling upwards. The flowers are not large draws for pollinators but, like many legumes, the leaves are a favored host plant of certain butterflies. Silver-spotted Skippers lay their eggs on this vine and their red-headed, chunky green caterpillars can often be spotted pruning its vegetation throughout the summer.
Groundnut gets this portmanteau of a name from its tubers. Their tubers are about the size of a fig and found in strings beneath the soil along its subterranean stem. These underground nuggets are where the vine retreats each winter and they were a staple crop of some Native American peoples. Groundnut was grown as an undomesticated crop by Native Americans and used as an emergency food source by colonists. The tubers are very starchy and can be prepared in many of the same ways potatoes traditionally are. Apparently, they taste quite good, like a nutty potato. Although never fully domesticated by modern farmers, Groundnut has a distinct advantage as a crop in that it fixes its own nitrogen. This increases its productivity in tired soils and means it can be used as a green manure, like soybeans, peanuts, and rye.
This week for Flora and Fauna Friday we have an unmistakably minuscule acrobatic busybody, the Ruby-throated Hummingbird (Archilochus colubris).
The Ruby-throated Hummingbird is our only species of Hummingbird that appears with any regularity in South Carolina. They are our smallest bird, weighing only a few grams at adulthood. This unrivaled smallness gives them many advantages, as well as handicaps, that I’ll touch on later. Our Hummingbird has a pointed head drawing into a long, narrow bill. Their stubby wide tail, short triangular wings, and itty-bitty delicate legs give them quite a dainty appearance. Both sexes are a dusty white beneath with a verdant green back that sparkles with iridescence. Females are drabber with a white throat, tail-feather tips, and cheeks. Males possess a black eye-stripe that flows atop their jowls and onto a hot stoked-coal throat that smolders in the light like a winter sunset.
Ruby-throated Hummingbirds are common throughout the state wherever ample food can be found. They are specialized to drink nectar and can only survive where there are sufficient nectar plants to sustain them. Many plants have specialized their flowers to encourage Hummingbird visitation. Plants such as Crossvine, Coralbean, Trumpet Vine, and Red Buckeye. The pollen bearing structures and nectar glands of these flowers are positioned so as to maximize Hummingbird interaction. These plants are certainly favorites but Hummingbirds will take anything they can get. They will readily feed from any flower that produces sufficient nectar, including many exotic and ornamental plants like Manettia and Zinnia. Yet, they do have a clear preference for red flowers. Hummingbirds are not afraid to accept handouts either and will stake a claim to a properly stocked hummingbird feeder. (On an aside, do not use dyed hummingbird feed in your feeder. The dye is unnecessary and potentially toxic to the birds. Plain sugar water is best.) In addition to nectar, Hummingbirds will eat small insects and spiders. They also drink from sap wells created by Yellow-bellied Sapsuckers. These birds are quite feisty despite their stature and spend a good deal of time fussing and fighting over flowers.
Hummingbird habitat is so dependent of food availability because the birds have a ludicrously high metabolism. Their heart rate can exceed 1200 beats per minute and they consume an obscene amount of calories just to stay alive. Due to their small size, their metabolism must compensate to keep their core body temperature high enough. Their small size also means they can’t store much extra energy as body fat. So the birds must eat constantly or they’ll soon starve to death. So why do these birds want to be so small? The answer to that is what makes Hummingbirds so unique.
Hummingbirds are the most agile vertebrate on the planet. They have the ability to fly three dimensionally. They can move up, down, left, right, forward, or backward in any combination of those axes. They can fly at 25mph or hover stationary in mid-air. Their small size, along with some unique physiological adaptations, make all this possible. Their wings beat dozens of times a second, allowing for extremely rapid and fine flight control. This maneuverability allows these birds to access food sources, mainly treetop flowers, which were practically inaccessible to anything but insects before. Feeding in flight and not perching to feed reduced their risk of predation as well.
This week for Flora and Fauna Friday we have a modest and irritating wildflower, the Spurge Nettle (Cnidoscolus stimulosus).
The Spurge Nettle is a small perennial wildflower found in drier sandy soils across Edisto Island. It has largish palmate leaves with three or five lobes. Unlike true nettles, it’s a member of the Spurge family, Euphorbiaceae. As I’ve explained before, this family has some unique and complex floral anatomy. However, Spurge Nettle has converted that anatomy to something resembling a more traditional flower. Spurge Nettle has a brilliant-white five-petal flower. The flowers are monoecious, each being either male or female. It blooms nearly year-round. They have a robust taproot which helps them hang on in the dry, sandy, and often disturbed ecosystems where they are found. This taproot is edible when cooked but probably better off left alone as I’ll explain below.
Spurge Nettle’s claim to fame is its defensive nature. Spurge Nettle is veiled in an aura of urticacious trichomes. Trichomes are the tiny hairs found on the surface of a plant. They come in many different shapes with a multitude of purposes on a plethora of plants. Urticacious trichomes are meant to irritate. These stinging hairs are found across every surface of the Spurge Nettle, except its flowers. They protect the plant from herbivores by causing severe pain wherever the stinging hairs can reach. This irritation is induced by a poison injected by the plant. These trichomes have a tip that’s not even sharp. Instead the point is round and slightly swollen, like the tip of a wooden drumstick. Upon contact with an offending individual, that swollen tip snaps off across the waist beneath it. Breaking like glass, it leaves behind a hollow and incredibly sharp shaft. This microscopically sharp hair immediately and effortlessly punctures the skin as the pressurized liquid poison inside is injected into an unsuspecting critter. These trichomes are tiny pressurized hypodermic needles. The toxin is mostly harmless to humans but can be incredibly painful depending on the level of exposure. Spurge Nettle is a plant that’s best appreciated in the woods and not in the bouquet.
This week for Flora and Fauna Friday we have “the big lizard”, the American Alligator (Alligator mississippiensis).
The American Alligator is not actually a lizard, it’s our only representative of Crocodilians on Edisto. There’s only one other Crocodilian in the United States, the American Crocodile (Crocodylus acutus), which is found exclusively in south Florida. Alligators are found in fresh, brackish, and even saline waters throughout the coastal plain. They have salt glands for removing excess salt from their bodies but they’re not that efficient at it. So they prefer to stick to Freshwater when they can. Alligators are ectotherms and thus rely on heat from the environment to stay warm. They’re primarily nocturnal but are often found basking on the bank in the heat of the day, soaking up the sun to help them digest. They can live over 50 years in the wild and males can reach 15ft in length and weigh half ton. Females are more petite, usually only reaching 8ft in length and 200lbs in weight. Alligators have indeterminate growth, meaning they grow continuously throughout life. American Alligators have one of the strongest bite forces of any animal and they principally use that power to crush turtle shells. Gators are the top of the food chain in South Carolina. They have no natural predators when fully grown, other than Bull Sharks in that one in a million instance where gator and shark cross paths. Despite this position in the pecking order, Alligators mostly eat fish, crabs, and turtles along with the occasional wading bird and Raccoon. Unlike Crocodiles, Alligators rarely go after anything they can’t swallow whole. However, those who tempt fate often find their date with destiny.
Alligators are a keystone species. They dig in the mud underwater to create depressions that hold water during droughts. These gator-made puddles are critical to the survival of fish and amphibians who inhabit shallow wetlands. Old Alligator nests do the reverse, creating dry hills in the swamp where other reptiles can nest and wetland trees and shrubs can take root. Somewhat counter intuitively, they’re the first line of defense for the nests of wading birds, like Egrets, Ibis, and Wood Storks. The single greatest danger to these bird nests are Raccoons. Raccoons love eggs and despite the birds nesting en masse over Gator infested swamps, Raccoons are still willing to make the treacherous swim for heron on the half-shell. Both Alligators and Raccoons are nocturnal and it doesn’t take a rocket-scientist to guess who’ll win that aquatic one-on-one. Although Alligators unintentionally protect fledgling wading birds, they won’t hesitate to make a meal of unlucky birds who fall from the nest.
American Alligators start life as an egg inside a mound of dirt and leaves on the bank of the water. A pile of detritus lovingly constructed by their mother. When the baby gators hatch, they begin calling for mama, who is most often lurking nearby. Mother Alligators protect their young for the first year or two of life. Baby gators feed on minnows, frogs, crawfish, and insects, transitioning to larger prey with age. Males can be quite territorial with each other. Mature bull gators (I believe the technical term is “big boys”) are known to kill, and subsequently eat, smaller males they find in their territory. This forces adolescent Alligators to flee to far off puddles in late spring to avoid predation. That’s why small Alligators seem to spontaneously crop up all over the Lowcountry every June. Bull gators court females with a bellow display. He floats with his back just below the surface of a glassy mire and forcefully exhales through his throat with a resonant, bassy growl that vibrates his entire body. This bellowing vibrato shakes the water around him, creating energetic ripples across its surface and presumably wooing the object of his affection.
Alligators are another conservation success story. Since Europeans first arrived in the Americas, native predators have been persecuted relentlessly. Wolves and Cougars were extirpated from the state, Black Bears nearly were, and Alligators were following suit. The Alligator’s only saving grace was their preference for inaccessible swampy habitat. However, even those murky havens were not safe from lumbering, draining, and filling. With the introduction of the endangered species act, the American Alligator was given a second chance. Because of their association with rookeries, the recovery of the American Alligator went hand in hand with that of the Wood Stork. Nowadays, with how thick our wetlands are with gators, you can scarcely imagine that the species was once so close to the brink!
This week for Flora and Fauna Friday we have a grandly floral, fragrant hardwood, the Southern Magnolia (Magnolia grandiflora).
Southern Magnolias are a native to the coastal plain of the South, growing naturally from Texas to North Carolina. Their granite-gray trunks hang high through the understory of the forest where their inky-green leaves devour the fragments of light that trickle down onto their waxy skin. This is a tree that’s playing the long game, much like the Live Oak. Magnolias are not as hardy or long lived as Live Oaks but they make up for it with unmatched crown density. Their giant hand-sized leaves permit no light to pass below them, overlapping like the shingles of a roof. They have the firmness of dry leather, an underside upholstered with fine cinnamon velvet, and a color so deep with green it seems black beside its woodland rivals. At maturity, the abyssal vacuum of light a Southern Magnolia draws beneath permits no competition. That solar monopoly allows a South Magnolia to live a comfortable life beneath the canopy of a forest. However, a life in the interstices of the forest is not the only destiny for today’s tree. Southern Magnolias are equally well-suited for life in the spotlight, quickly reaching an impressive size in full sun. This is their plan from the start. Waiting in the throes of the forest for a neighbor to succumb to the hardships of life, a Southern Magnolia will seize any opportunity to break for the atmosphere. Supplanting the fallen plant in the oligarchy of the canopy and claiming its empire of dirt with the shadow it pours over the land. There it may stand for a century. Uncontested on its homestead of clay and sand. A patch of soil littered with leaves and fruits from years past and nothing more.
Magnolias are an ancient group of flowering plants. The quirks of their archaic origins are best observed in their flowers. Southern Magnolias produce a monstrous bloom more than a foot across. Petals pure from any color mirror the parasols of dark leaves. These china-white bowls bellow out an oppressive soft-smelling sweetness into the passing wind. A scent that saturates the air in an olfactory fog. At the center of the flower sits an egg-shaped structure on a pedestal. This cone-like feature is topped with stout curls of stigmas and skirted by cream-colored anthers, arranged like sticks in the pages of a matchbook. The entire flower is awkward and primitive compared to other flowering plants. What’s interesting is its preferred pollinators. Magnolias do not rely on bees, wasps, butterflies, regular flies, or even bats for pollination. When Magnolias entered the scene, there were no pollinators. So they enlisted the help of unsuspecting beetles. Beetles are rather clumsy pollinators, often damaging flowers in the process of pollination. Thus Magnolia flowers are adapted to be quite robust and resilient. Eventually the matchstick anthers and ivory leather petals fall away and only a warty “cone” remains. This cone grows and hardens into the fruit of the Magnolia, blushing a rosy red across its lime green skin as it ages. When ripe, the fruit splits, offering glistening scarlet seeds to the world that dangle from their cradle by silken threads, swaying precariously in the breeze. Their seeds are coated in an edible layer and eaten whole by birds, who disperse the seeds to off.
This week for Flora and Fauna Friday I present the prismatic metallic beetle that picks up after your pets, the Rainbow Scarab Beetle (Phanaeus vindex).
The Rainbow Scarab Beetle is an acorn-sized beetle, at about half to three-quarters of an inch, with an overall blocky appearance. It has a heavily textured exoskeleton on the thorax and head, reminiscent of crumbled aluminum foil, as well as ridges running down its elytra, the wing plates. What sets the Rainbow Scarab Beetle apart from the rest, as you may have surmised from the name, is its carapace of many colors. This Beetle has the sheen of heat-treated Titanium. Their black underside plays the backdrop for their rainbow top. Their head and the sides of their thorax are an iridescent brass that shifts to emerald-green, the mantle of their thorax gleams of garnet with hints of amethyst, and their eleytra shine of apatite beset by emerald and brass. If that’s not enough to distinguish this beetle, the males possess a mammoth black horn on their head and a broad triangular plateau on their thorax. Now that’s a handsome bug!
What’s not so handsome is their dietary habits. Rainbow Scarab Beetles are Dung Beetles, a group of Beetles that feed exclusively on animal waste. Both the adults and larvae of this species feed on the same thing. A male and female Scarab will meet each other over dinner. If they hit it off, they’ll each construct a burrow beneath the feast, to act as both cradle and pantry for their offspring. Eggs are laid within these subterranean deposits where their larvae will grow and emerge the following year. Although this habit is unsavory, these colorful critters play an important role in our ecosystems. They are one of many small cogs necessary for healthy nutrient cycling in the environment. When a plant draws nutrients from the soil and an animal eats that plant, those nutrients are transferred into the animal and away from the soil. The excess that is discarded by that animal returns to the soil but, without the help of Dung Beetles, it would either be consumed and dispersed again by flies or remain in the top soil were it can easily be washed away by rainwater runoff. Runoff from animal waste into river systems is a huge concern for water quality, even here on Edisto Island. Dung Beetles help to sequester this waste by burying it deep in the soil. This prevents nutrient runoff. Additionally, it helps to improve soil quality by moving nutrients below the topsoil and reducing soil compaction from the burrowing action of the Beetles.
This week for Flora and Fauna Friday we have the proud symbol of freedom and American exceptionalism, the Bald Eagle (Haliaeetus leucocephalus).
The Bald Eagle is the largest raptor in South Carolina. It’s an unmistakable and profound bird to behold. Their shadowy wings, held wide and true, spread eagle across the sky eclipse the clouds. Their head crowned a snow-white summit and tail a trailing cirrus cape. Perched on golden legs anchored by toes tipped with coal-black sickles. Piercing yellow eyes, so sure and resolute, bore out abreast a stout hooked bill of similar shade. A straight posture, stiff held wings, and expressive face radiate an aura of pride and self-assured confidence.
Bald Eagles build massive nests near water in the crooks of tall, mature trees. The birds mate for life and reuse the same nest year after year, until either the tree collapses or the nest is stolen by a Great Horned Owl. These nests can exceed 10 feet in width and weigh over a ton. Bald Eagles usually hatch two chicks each year and it takes a bird 5 years to reach maturity. Bald Eagle are carnivorous but primarily piscivorous. They mostly eat fish caught from rivers or lakes but are quite fond of waterfowl, rabbits, rodents, and carrion too. They are particularly fond of American Coots (Fulica americana), a strange and social waterfowl that is most closely related to Rails. They can also commonly be spotted dining on fresh carrion with Turkey Vultures.
Bald Eagles secure their prey using their awesome eyesight, robust talons, and sheer bulk. Eagles have the best long-distance vision of any animal. They can see roughly eight times farther than a human and can discern a far wider spectrum of color than us. This allows them to identify and focus on camouflaged prey at a distance of two miles. That’s about the maximum distance an unaided human eye, in ideal conditions, could identify a human silhouette as something other than a speck. Realistically, it’d be about the distance you could identify a horse. (For visualization, two miles is the distance from the top of the McKinley Washington Jr. Bridge to Jehossee Island, which is along the South Edisto to the west. Now imagine trying to a rabbit from there!) After an Eagle hones its laser focus onto its prey, it approaches low, swings its legs forward, and simply scoops up its dinner using its momentum and curved claws like grappling hooks. Their considerable size lets them take larger prey than most raptors and allows them to bully Ospreys and Foxes into surrendering their kills. They’ve even been trained by falconers to attack and disable drones!
As you may know, Bald Eagles almost went extinct. They were one of the many victims of rampant insecticide misuse in the middle of the 20th century. Chemicals like DDT were sprayed on crops to kill agricultural pests. These pesticides were miraculously good at that job. However, the chemicals did not biodegrade and were commonly misused by farmers at extreme excesses. When it rained, DDT was washed into streams and rivers by rainwater. Here the chemical was absorbed by microscopic bacteria and plankton. These plankton were the basis of the aquatic food chain and were themselves consumed by insects and minnows. Who were eaten by small fish, that were eaten by larger fish, which were then eaten by Bald Eagles. At each step in this food chain the concentration of DDT in the animal increased exponentially. The chemical accumulated in the animals’ flesh over the course of their lifetime, until it reached lethal levels for Eagles. DDT has the interesting side effect of inhibiting the proper development of bird eggs, making the shells brittle. This leads to the eggs being crushed during incubation. Bald Eagles were large birds that were slow to mature and sat atop an aquatic food chain. Because of this, they were hit harder than any other species by the effects of DDT. Luckily, through rigorous government protection campaigns and the banning of DDT, the Eagle has made a full recovery and has been removed from the endangered species list.
Nowadays, Bald Eagles are safe from pesticide contamination but face a new more surreptitious threat in the Southeast called Avian Vacuolar Myelinopathy, or AVM. It’s a nervous system disease that affects birds. It’s caused by a toxin found in a certain species of cyanobacteria. (Cyanobacteria are an immensely diverse group. They are photosynthetic and found in every body of water.) How does this toxin get into the Eagles? It gets there from the American Coots I mentioned before. How does the toxin get into the Coots? An invasive aquatic plant called Hydrilla. The species of cyanobacteria at fault grows on the surface of the Hydrilla, whose leaf shape promotes their vigorous growth. Far more vigorous than on any native vegetation. The Coots scarf down the Hydrilla, along with the cyanobacteria, and develop AVM. This disease causes muscular discoordination, leaving the birds unable to fly or swim well. Coots congregate in large rafts that are often over 100 birds strong. They use their numbers to confuse predators. Their densely packed numbers make it hard for an Eagle to focus on one specific bird and allows the Coots to dart out of the way at the last second. When a Coot develops AVM, it can no longer keep up with the raft. The sick Coot falls behind and gets singled out by the Eagle. Since they’re so easy to catch, Bald Eagles in AVM affected areas are preferentially eating sick Coots. Just like DDT, this toxin bioaccumulates and every AVM stricken Coot the Eagle eats intensifies the symptoms, until the Eagle succumbs to the same fate. Hydrilla is a non-native plant that takes over lake systems. Its harmful effects on the environment extend far beyond just Bald Eagle deaths. SCDNR is actively and feverously working to destroy the species anywhere it occurs in the state.
