Yesterday, on the leading edge of the snow storm, rain turned icy, pelting the woods with interesting nouns-that-should-be-verbs: rime and graupel. This bombardment made for delicious sounds, and not just on the human tongue.
Here is the percussive beat of this snowy ice falling into the marcescent leaves of a young beech (heard best with headphones):
In .wav format:
In case your browser doesn’t like .wav, the same recording, in .mp3 format:
Next morning, Junebug and I had the pleasure of making the first tracks on the snowy trails, listening to the whomp and whisper of the woods.
The temperature dropped to minus five last night (minus twenty for disciples of Anders Celsius), the coldest that I’ve seen in Sewanee. I took a walk in Shakerag Hollow this morning to see how the woods were faring in this unusual chill. I’ve never experienced such silence here. The quiet was punctuated by woodpeckers drilling meager breakfasts from high in the canopy and trees occasionally snapping out gunshot sounds as their wood shattered. No sign of wrens, titmice, chickadees. The forest floor was mostly clear. Only a few deer tracks. Most birds and mammals are in hunker-down mode.
Amazingly, given the cold, the springs were still running. This flowing water created some beautiful ice formations on the rocks all around. When water vapor rises from the stream, it hits cold, dry air. This is an unstable mix, ripe for an encounter with a pointy nucleation site: an icy strand of moss or rock edge. Once they get started, these crystals build on themselves, growing “flowers” from the air. An icy foreshadow of the spring ephemerals? The largest ones are a couple of inches across. Similar formations are found in polar seas and host very unusual communities of bacteria.
So welcome to Tennessee, Polar Vortex. Here are your blooms:
The coming wave of songbird migration has plants getting excited: finally they can get the kids out of the house before winter’s rigors set in. As thrushes, vireos and warblers move southward by the millions, their hunger creates an opportunity for seed dispersal that many plants have grabbed with enthusiasm. Look around in the late summer woods and you’ll see berries fattening up, preparing the bribe for passing birds. Bright red is the color of choice, the hue most likely to seduce an avian eye, so berries tend toward the garish, not the subtle blush.
We’re a few weeks away from the peak of migration (late September through early October brings the largest numbers), but the plants are ready. These eager food vendors include spicebush, dogwood, yellow Mandarin, Jack-in-the-pulpit, and Solomon’s plume.
Yellow Mandarin has an interesting family tree. It has a few siblings in North America, but all its other close relatives are Asian species. This whole clan was for years classified in one genus, Disporum, but the North American species are now recognized as distinct enough to merit placement in their own genus, Prosartes. Solomon’s plume and Jack-in-the-pulpit also have close relatives in Asia. This Asia-America connection is echoed by the biogeography of many other species, especially among the plants of the Southern Appalachians which often have close affinities to species in East Asia. Boufford and Spongberg, scientists from the Harvard Herbaria, summarized the situation:
The similarities of the forests of Japan, central China, and the southern Appalachians in appearance as well as in ecological associations are in many instances so great that a sense of déjà vu is experienced by botanists by one of the regions visiting the other.
The list of Appalachian species with very close East Asian kin is long and, surprisingly, is much longer than the same list for plants with close kin in western North America. Japan is closer than Oregon, it seems. A few of the more familiar examples include: tuliptree, magnolia, dogwood, Virginia creeper, mayapple, ginseng, partridge-berry, blue cohosh, witch hazel, and honey locust. And, of course, the aptly-named “Mandarin.”
Donoghue and Smith’s analysis of this pattern concludes that close evolutionary connections between East Asian and Eastern North American species are “exceptionally common in plants, apparently more so than in animals.” Their work suggests that “many temperate forest plant groups originated and diversified within East Asia, followed by movement out of Asia at different times, but mostly during the last 30 million years.”
These botanical connections are reminders that Asian and American temperate forests were once connected, a connection that was severed as the world dried and cooled in the late Cenozoic. But it is also the result of a few long-distance dispersal events between climatically similar areas.
Animals move to the beat of a different biogeographic drummer. Their kinship patterns are more predictable: western and eastern North America share many close relatives, connections south to the tropics are also common.
So the migration of American birds is powered by Asian food. The botanical restauranteurs hope that the birds opt for the take-out option, carrying seeds away from the parental storefront. Most of these seeds will land a few meters from the parents, but a very small number might make a huge leap, perhaps landing in southern Mexico or on the coast of South America. There, they’ll likely perish. But the biogeographic future is written by the one or two that can put down roots and flourish.
The same is unfortunately true for plant diseases. A few long-distance migrants are reshaping the forests of the world. It is no accident that so many of the more notable plant-killing invasive diseases in the Southern Appalachians have their origins in Asia. Once they get over here they find a “home way from home,” minus the constraints that they experienced in their homeland.
I’ve rambled about the color red before, both here on the blog (“Quite possibly the most overused image of North American birdlife”) and in The Forest Unseen (“November 5th — Light”). I’ll note briefly here that until the leaves fall in a few weeks, the plants face an uphill battle against the physics of light in the forest. It is dark in the woods these days (photography is impossible without steadying the camera on my boot or using a flash). The summer tree leaf canopy is not only robbing most of the light, it is selectively stripping out the reds. Only when a shaft of sun sneaks through a canopy opening do these fruits truly shine. As autumn comes on, the botanical beacons will light up more often.
Thrushes: get ready.
This little snail is an evolutionary oddity, a fish out of water. I found this particular individual clinging to a tree in the upper reaches of Shakerag Hollow. The common name is “globular drop,” quite appropriate given its pea-sized shell and rotund shape. The shell is very thick and feels like a pebble.
Unlike all other land snails and slugs in our region, this species belongs to the family Helicinidae, a group of mostly tropical land snails that are more closely related to the marine snails than they are to other terrestrial snails. The animal’s body reveals this kinship: it has an operculum (a “trap door”) with which it seals its shell when withdrawn, it has just one pair of antennae (other land snails have two pairs), and its eyes are located at the base of the tentacles instead of at their tips. These seemingly minor differences indicate a deep divergence, analogous perhaps to the difference between a bird and a bat. Like birds and bats, the two lineages of snails independently evolved the ability to live in a new habitat — creeping onto land. Not quite as impressive as taking wing, but then what use is a radula in the air?
The following photographs are from another individual, one that lived in the limestone at the bottom of the mountain.
The common name for this wasp-mimicking fly is “news bee” or, more optimistically, “good news bee.” The moniker was given to the insect for its habit of zipping through the air toward a human then holding steady, imparting the news in a loud buzz. Once the news has been sung, the fly flings itself away to find another willing ear.
This habit might also account for the generic name of the species, Milesia (this one is Milesia virginiensis, I believe). Milesian tales are lurid, captivating short fables, named for Aristides of Miletus, “a writer of shameless and amusing tales with some salacious content and unexpected plot twists” (or so says that rock of classical knowledge, Wikipedia). A fly’s version of a Milesian tale would be fun to hear, but regrettably I could not translate the buzz that I heard in Shakerag Hollow and so missed this Dipteran’s narrative complications and witty innuendo. Maybe you can do better: my recording of the insect follows. The fly was perched on a leaf, washing its forelegs. Suddenly it launched itself and flew to me to give The News. Once done, the fly darted away to gossip at a fallen tree, then shot out of earshot.
(Web browsers differ in how they handle sound files, so I have uploaded two files: the first is mp3 and the second is m4a. You’ll either see a “play” button, an option to download, or both. The background sounds are cicadas and a Carolina wren.)
A Celandine Poppy was blooming in Shakerag Hollow this morning. I was delighted and surprised. Delighted because these are the forest’s most gorgeous flowers; surprised because the plant’s timing is unusual. Most of the plants of this species bloom in March or April, before the trees leaf out, before the summer’s heat.
Celandine poppies can self-fertilize, so the absence of other flowers will not prevent this individual from setting seed. This is a good thing for the future of wildflowers. In a changing world, the natural variation present in all populations allows species to adapt and change. So creatures who “deviate” from the norm give species new genetic pathways to the future. The unexpected sight of this flower is therefore both a sensory delight and a reminder of life’s beautiful variability and adaptability.
I’d been sitting on the dead ash log for a good thirty minutes before I noticed that I had company. The rattle caught my eye — what an odd piece of vegetation — then the whole snake popped into consciousness — whoa! The animal was curled catlike, its nose and tail resting on the body. It did not move one tiny little bit for the hour that I watched.
I returned the next day found the snake coiled in exactly the same place, its body shifted slightly. Still very hard to see:
By coincidence, I received a frozen road-killed rattlesnake this week from some colleagues whose vehicle accidentally violated the revolutionary imperative: Don’t Tread on Me. This allows a closer look at the source of the phobias that have etched snakes into the deepest parts of our subconscious (religious allegories, anyone?).
In pulling open the mouth to get a photo, I managed to spike myself on the lower teeth. So when asked whether I’ve ever been bitten by a snake, I can now answer No, but I’ve bitten myself with a rattlesnake. Another entry in the Annals of Zoological Stupidity. As it happens, this week I’m reading David Quammen’s excellent new book, Spillover, which is full of tales of microbes leaping into humans through pin-prick wounds. So far, the end of my thumb shows no sign of incubating the next zoonotic pandemic.
If these images fang you with fear, let me add that I’ve spent thousands of hours in Shakerag Hollow and this is the only close encounter I’ve had with a rattlesnake.
The timber rattlesnake is declining across most of its range due to habitat changes, road mortality and direct persecution from people. In its former territory in the Northeast, sightings are very rare indeed. In the snakes’ place, plagues of tick-bearing small rodents tromp merrily through the woods, their enemy defeated.
A jumble of sandstone debris lies a few meters from the base of a high cliff. The rocky blocks are the size of wardrobes, small cars, houses. A fallen tree crowns the heap and thick grapevines crawl over its fissures. From a deep crevice, vapors of ammonia reach out and punch me in the nose: aha! Promising.
I clambered up here after seeing a black vulture take flight from a low branch above the rocks. Black vultures do not usually roost so low or in such deep woods. I suspected that the vulture might have an interesting reason for choosing this unusual slumbering spot. So I hauled myself onto the rocks, then tip-toed across their angled surfaces.
First the smell, then a beautiful sight: the random tumble of rocks created a passageway leading to a small underground chamber. If I crawled down there I could just about crouch in place or curl up on the ground to sleep. But going farther was out of the question. Rough-edged, deep hissing emerged from the gloom a few seconds after I peered down the entranceway. The message is clear enough: “Do not disturb.” Unheeded, the message will intensify, turning to a spray of hot vulture vomit. These parents want no visitors as they incubate their eggs. I backed off straight away.
A couple of weeks later I made another brief visit to peek at the hatchlings and to leave a small infra-red triggered camera in a rock crevice several meters back from the nest. I left the camera in place for 24 hrs to see what the parents were up to.
Vultures are loaded with metaphor: they nest in tombs, lower than any other bird, foreshadowing their role as ecological undertakers. But when they walk out of The Cave of Childhood, they enter adult lives that are spent on the wing, avian prayer flags that fly higher than all others: defiers of gravity, lifting dead remains away from the pull of the sepulchral Earth.
Evolution may have robbed vultures of their rightful inheritance as birds — voices and gay plumage — but it seems to me that they sing and shine nonetheless. The vultures’ response to these acrobatics would, I suspect, be a shrug of the dark wings. For now, a dead ‘possum delivered to eager mouths is philosophy enough.
Glaucon answers, Yes, very natural.
Scaly, brown digits poke from the underworld, pointing skyward. They look slightly disturbing, like bloated pine cones or partly rotted corn cobs. These protrusions are the flowering parts of Conopholis americana, a plant that grows attached to the roots of oak trees. Conopholis has turned its back on its botanical inheritance: the plant has no chlorophyll. Instead it lives as a parasite, feeding on another species’ labor.
One of the common names for the plant is “bear corn,” an apt name for a plant that plays a surprisingly important role in the life of bears in eastern North America. Even though Conopholis is hardly an abundant species, the plant comprises ten to fifteen percent of the diet of bears in the Smoky and Shenandoah Mountains. When the total annual energy content of various botanical “bear foods” is added up, acorns top the list (67% of available energy) but amazingly Conopholis comes in second (16%). Although some websites and books claim that the bears eat the whole “cob,” biologists who have actually witnessed bears dining on the plant report that it is the little fruits that interest the bears, not the whole flowering stalk. I suspect, though, that the sample size for these observations is quite low…
The productivity of Conopholis in terms of energy provided per hectare is consistent from year to year, unlike blueberries and acorns whose fruitfulness can be highly variable. This, along with the early fruiting of the plant, make the species particularly important for wild bears. Lactating mother bears are said to be especially dependent on the plant.
So one way or another, oak forests nourish bears: bear corn in the late spring from parasites on roots, blueberries and other delights in the light summer shade of the oak understory, and acorns in the autumn. All this is evidence for the Ursic principle: the idea that the Universe as we know it seems wonderfully designed to bring about that supreme pinnacle of life, the bear. Black-robed bear philosophers rightly point out that an objective analysis of the data strongly supports the notion that the Universe’s parameters are improbably fine-tuned and that this fine-tuning has bear written all over it. Other thinkers, mostly grizzly bears, believe that these woods are just one of many realities. An infinite number of realities exist in this Multibearse, only some of which contain bear corn.
- Life History Studies of Conopholis americana (Orobanchaceae). Wm. Vance Baird and James L. Riopel. American Midland Naturalist , Vol. 116, No. 1 (Jul., 1986), pp. 140-151
- Production of Important Black Bear Foods in the Southern Appalachians. Roger A. Powell and D. Erran Seaman. Bears: Their Biology and Management , Vol. 8, A Selection of Papers from the Eighth International Conference on Bear Research and Management, Victoria, British Columbia, Canada, February 1989 (1990), pp. 183-187
- Seasonal Foods and Feeding Ecology of Black Bears in the Smoky Mountains. Larry E. Beeman and Michael R. Pelton. Bears: Their Biology and Management , Vol. 4, A Selection of Papers from the Fourth International Conference on Bear Research and Management, Kalispell, Montana, USA, February 1977 (1980), pp. 141-147
- Energetic Production by Soft and Hard Mast Foods of American Black Bears in the Smoky Mountains. Robert M. Inman and Michael R. Pelton. Ursus , Vol. 13, (2002), pp. 57-68