from the woods near Natchez, Mississippi, USA
February 8, 2004
Thursday was a rainy day here. We got exactly 5 inches (13 cm) as a front stalled atop us. The rain seems to have stirred the crawdads, for by Friday morning new crawdad chimneys were appearing in a low spot down next to the pond. Crawdads, also called crayfish and crawfish, are crustaceans very much like small lobsters. When they dig burrows in wet ground they dump their mud right at the hole's edge so that a mud "chimney" develops. You can see a doozy of a crawdad chimney at www.biosurvey.ou.edu/okwild/misc/cfchim.html
As a kid in Kentucky crawdad chimneys were extremely commonplace on our bottomland farm but now I don't see so many. Probably that's because stream channelization has lowered the water table everywhere and because crawdads are very susceptible to pesticide runoff.
In the US we have over 250 crawdad species in three different genera, and they can be hard to identify. I'm guessing that the ones building chimneys in our fields are the common Chimney Crayfish, CAMBARUS DIOGENES. You can see that species and others at www.fcps.k12.va.us/StratfordLandingES/Ecology/mpages/crayfish_(cambarus).htm
Being right across the river from Louisiana we can't ignore the fact that each year more than 10 million pounds (4.5 million kg) of crawfish are harvested just from one area in that state. The ones known as "Red Swamp" and "White River" crayfish are the type being farmed. There's a lot of information about crayfish farming at www.crayfishfarming.com/page3.html
Despite crayfish farming being such an important industry, surprisingly little seems to be known about crayfish life history. One study I've read indicated that crawdads stick pretty close to their burrows, defend them from other crawdads, and that larger crawdads may oust smaller ones from their burrows. A crawdad's burrow seems to be the focal point of its life, and when we remember how many predators love to eat them, that's understandable.
By the way, my very first money-making venture as a kid was to set up a booth along our gravel road where I sold to local fishermen the immature crawdads I'd seined from a local ditch.
CRAWDAD, CRAYFISH, CRAWFISH...
Back in Kentucky any farmboy calling a crawdad a "crayfish" or a "crawfish" would have been suspected of trying to sound snooty, and maybe it's the same way in Mississippi.
Etymologists suspect that all three terms for crawdads originated with the Old High German word "Krebiz," which simply meant "edible crustacean" (In modern German "Krebs" means "crab"). Old French speakers borrowed the word and softened it in their Frenchy way to "crevise," which is first recorded in a document written in 1311-1312. When the English lost at the Battle of Hastings in 1066, the conquering French- speaking, Viking-descended Normans brought their "crevise" with them, but the tin-eared Brits thought they heard "fish" at the end of that word. The first "crey-fish" spelling appears in 1555. By that time the rapidly evolving, hybrid Anglo-Norman language that would become our English represented the word for crawdad with at least two pronunciations, so eventually two forms of the word passed into Modern English: crayfish and crawfish.
So where does the "dad" in crawdad come from? That's harder to explain, but it seems to arise from the general impulse among Southern country people to be colorful and folksy with their language. Maybe it has something to do with what the crawdad looks like when he's in his burrow looking up at you with his claws ready, like a grumpy old man at his frontdoor.
Thursday's rain also stirred up the Upland Chorus Frogs, Southern Leopard Frogs and Spring Peepers who have been calling in our ponds for the last month or so. Right now if you look closely into the ponds' waters you can find frog eggs. They look like little gobs of clear jelly stuck to grassblades and weed stems, or sometimes just floating freely at the water's edge.
Frog eggs are worth thinking about. For one thing, the whole frog-egg scene speaks to us of one of the most dramatic moments taking place during the evolution of life on Earth.
The fossil record shows that about 390 million years ago, during the Devonian Period, species of FISH began appearing with lungs, as well as awkward looking appendages enabling them to move about on land. About a million years passed and then, between 300 and 250 million years ago, land-based animal species we can recognize as amphibians began showing up with even more refined adaptations for life on land. The major events in this gradual evolution from fish to amphibians are described in detail, fascinating illustrations based on critical fossils that have been discovered are presented, and links with more information are provided at www.myherp.com/articles/other/evolution.htm
The earliest amphibian fossil with definite froglike features is 250 million years old. The fossil of the earliest "true" frog is from the Early Jurassic era (188-213 million years ago). Thus, perfectly respectable frogs were around BEFORE most of the major groups of dinosaurs appeared. Frogs are of a more ancient lineage than dinosaurs.
Reptiles arose from amphibians, same as amphibians arose from fish. Here are three new adaptations that arose with the reptiles -- adaptations for dry land which frogs and other amphibians do NOT have, but which reptiles DO have:
- scales that keep their bodies from drying out
- better body-temperature regulation
- an ability to reproduce on land
That last point brings us back to frog eggs. For, eggs laid on land need shells to protect them, but Mother Nature didn't "invent" eggs with shells until she came up with reptiles. Therefore, frogs and other amphibians must return to water to reproduce, and that's why frog eggs are laid in gelatinous masses nearly always in water, not as individual eggs with shells, on land. Where reproduction is concerned, amphibians are more like their fish ancestors than their reptilian descendents.
When frogs mate, the male rides atop the female grasping her trunk. As the female discharges eggs into the water, the male sheds his sperm on them. In other words, male frogs don't need or have penises. When the clear, jellylike albumin in which the eggs are embedded is extruded from the female's body, it imbibes water and swells. Later, we can watch tiny frog embryos developing as they hang suspended inside the gelatinous mass.
How beautiful that frog eggs, and frogs themselves, should survive until now, as living, evolving relicts of an event in evolution occurring so many millions of years ago. During recent nights this week as I lay thinking of all this, it seemed to me that the frogs' echoic chiming shimmered with antiquity. When I saw the frogs themselves, their ungainly shapes beautifully expressed the awkward but vigorous, primal, unrefined impulse that characterized those early times of vertebrate evolution. The shape of a frog is like a pioneer country boy who does his job very well in his own crude way.
On my nature site's Frog Reproduction page you can see frog eggs, and above the egg pictures you can view two mating frogs photographed by my neighbor Karen Wise. The pictures are at www.backyardnature.net/frogs.htm
A technical discussion of frog evolution appears at http://tolweb.org/tree?group=Salientia&contgroup=Living_Amphibians
FIRST BLUEBERRY BLOSSOMS
Last Sunday, February 1, head-high, wild blueberry bushes in the woods here produced their first flowers for this season. I'd been waiting for them, checking on the buds each day, because the buds had become very conspicuous, filling me with expectation. Like BB-size pineapples with bright red scales, they adorned densely wispy, leafless, vibrantly green stems. I was also eager for these buds to burst because I wasn't sure which blueberry species this was, and I needed blossoms for an identification. The University of Mississippi's "Mississippi Plant Checklist" lists nine wild-growing blueberry species for the state.
It turned out that the species flowering so prettily now goes by the book name of Elliott's Blueberry, VACCINIUM ELLIOTTII. Like all blueberries, it's a member of the Heath Family, in which you also find azaleas, huckleberries and the Sourwood tree. The waxy-white, cylindrical, ¼-inch long (7mm) flowers of Elliott's Blueberry are somewhat unusual in that they emerge before and during leaf expansion. Right now, the white flowers subtended by crimson scales on green stems is very pretty. A montage of pictures showing the flowers, green stems with reddish buds and other features can be viewed at www.cnr.vt.edu/dendro/dendrology/Syllabus2/velliottii.htm
THE MISSISSIPPI PLANT CHECKLIST
Plant identification in Mississippi is encumbered by there being no comprehensive "Flora of Mississippi" -- such as Radford's "Flora of the Carolinas," or Correll & Johnston's "Manual of the Vascular Plants of Texas." East of the Mississippi River, no region of the US is as understudied as ours.
If you're trying to identify a Mississippi plant or animal using a publication focusing on the organisms of a different region, you just don't know whether the thing you're trying to identify is included in that publication. In such cases, often it's helpful to have a list of all the organisms of the kind you are trying to identify found in Mississippi. That way, using floras and manuals from other states, sometimes you can identify a Mississippi species through the process of elimination, by checking names off the list as you read about them in publications meant for other states. That's how I figured out the Elliott's Blueberry mentioned above. I found a list of all known native species of Mississippi blueberries at www.herbarium.olemiss.edu/echecklist.php?genus=Vaccinium
To find lists of other kinds of plants, go to www.herbarium.olemiss.edu/fchecklist.php and click on the plant's family name.
One problem with this approach is that if I had not known that the technical name for the blueberries' Heath Family is ERICACEAE, and that all blueberry species belong to the genus VACCINIUM, I'd have been unable to make sense of the lists provided on the Mississippi Plants Checklist page.
Of course you can find out the Latin names for plant families and genera in most general-public-oriented wildflower and tree books. This is an awkward approach, but if you're serious about getting accurate identifications for Mississippi plants, it's worth the effort to master the process.
As is made clear at my Web site called "Loess Hills of the Lower Mississippi Valley" at www.earthfoot.org/loess/loess.html, land in the Natchez area and throughout much of western Mississippi is mantled with a thick layer of loess. Loess is a special kind of silt deposited by the wind at the end of past ice ages.
The other day Leon up near Vicksburg, where loess lies 200 feet deep (60 m) and more, wrote describing problems he was having. He lives at the base of a terraced loess cliff. The terraces are now becoming honeycombed with tunnels, and he's nervous because he knows that disturbed loess, when wet, turns to water-gravy.
It was hard to find anything encouraging to say to Leon. As long as loess lies just as it was deposited 17,850 years to 22,000 ago, it's pretty stable stuff. However, if an armadillo digs a hole in a loess bank, before long that hole becomes a gully. If a tree root grows through the loess, when the tree dies and the root disintegrates, water begins trickling along the channel left by the root, and before long you have a gully. In fact, just about any disturbance in loess inexorably leads to a gully that inexorably grows and grows.
In the old days people understood and respected this feature of loess. Road engineers made road cuts through loess with vertical walls, leaving alleys that remained stable and picturesque for decades. Nowadays trees are cut way back from roads, and road cuts are provided with broad, shallowly sloping sides. Nothing could be more inviting to erosion. If you travel this area, just look at the outrageous gullies forming in those wide, new road cuts, even before the road- department's grass seed germinate. And wherever there's a loess bluff at the edge of town, look how people are cutting back forest and building expensive houses right at the edges of those bluffs.
By the way, the pronunciation of "loess" is such a contentious matter that I provide a special page on the subject at www.earthfoot.org/loess/pronounc.htm. I pronounce it more or less like "lerss," but with a special curl in my tongue I could never accomplish without having spent a goodly part of my life trying to pronounce the German "ö".
ALGAE IN MY BATHTUB
Just a couple of weeks ago I cleaned out the old bathtub next to the barn, then rainwater draining off the roof filled it, and already its white sides are green with algae. I'll bet that with a microscope I'd find little critters grazing on that algae, too. I've read that a cubic yard of air can contain millions of microorganisms, the most common being fungi, bacteria, and viruses, but my bathtub proves that many kinds of algae and protozoa, even those usually associated with water, go aloft, too.
It's especially astonishing that so much life is suspended in the air around us when you consider that air contains such small amounts of available water and carbon, which are so necessary for Earth-life in general, and in the air there's little protection from the sun's ultraviolet radiation. For these and other reasons, most airborne plant and animal microorganisms do not travel as full-fledged organisms, but rather as thick-walled spores or cysts that germinate when they land in a good place. Different organisms can survive being suspended in the air for varying lengths of time. According to lecture notes found on the Internet, cholera survives only about 5 minutes, typhoid about 10 minutes, TB organisms about a week, but anthrax can survive up to 50 years, and certain bacteria (Coryneform & Actinomycetes) up to 10,000 years.
One technical name for living things that hang suspended in indoor air and which often cause allergic reactions in humans is "bioaerosols." You might be interested in North Carolina State's "Bioaerosols In the Human Environment" page dealing with mold, dust mites, fungi, spores, and pollen at www.ces.ncsu.edu/depts/fcs/housing/pubs/fcs3605.html
DON'T FORGET THE BIRD COUNT
As reported in the January 18th Newsletter, the Great Backyard Bird Count of 2004 takes place next weekend, February 13-16. Read more about it at www.birdsource.org/gbbc/index.html
FROG EGGS & RELIGIONS
One morning this week while listening to Public Radio I wandered over to the little pond beside the barn to check on the frog eggs mentioned earlier. While admiring them and cogitating in the manner outlined above, the radio reported that officials in Georgia sought to remove the word "evolution" from that state's school curricula.
That juxtaposition of my frog-egg reverie with the news from Georgia cast me into a certain combative mood. How dare they seek to rob me of one of the most important words I use when cataloguing the wonders I ascribe to the Creator. This news from Georgia got me to thinking this: Maybe now is as good a time as any to clearly and concisely explain why I am so anti- religious -- why I am a hardcore, dyed-in-the-wool PAGAN.
It is precisely because I regard all religions as artificial, unnecessary barriers between people and the higher states of spirituality to which they naturally aspire.
We look into the heavens, experience love, or contemplate frog eggs, and we become aware that something, somewhere, has created these marvelous things and circumstances, and that this Creator and the creation itself are worthy of adoration. Human spirituality begins like this and should continue through our lives in the same vein, perpetually growing and maturing. The highest calling of every community should be to nurture its citizens' quests for spirituality, to inspire them toward ever-more exquisite sensitivities and insights, and to encourage them to love, respect and protect that tiny part of the creation into which we all have been born.
Instead, religions divert the energies of our innate spirituality-seeking urges into the practicing of mindless ceremonies and rituals having little or nothing to do with the majesty and meanings of the universe. Religions insist that we must disbelieve the evidences of our own minds and hearts, and submit to primitive scriptures interpreted and transmogrified by untold generations of clerics who, history reports, all too often have hustled to promote their own bureaucratic and political agendas, and continue to do so today.
In my opinion, anyone wishing to "get right with God" should begin with cleansing from his or her own life all traces of religion. And the first step in doing that is to get straight in one's mind what is religion (dogma in scriptures), what is spirituality (one's personal relationship with the Creator and the creation), and what is love (intense empathy and well- meaning). You do not need to believe in someone else's curious dogma in order to be spiritual, or to love your neighbor and do good works.
Finally, why is a diatribe like this appropriate for a naturalist's newsletter? It is because this newsletter springs from my passion for all that is natural -- the Creator's Earthly creation. Natural things on our planet are now being destroyed at a rate greater than at any other time in the history of the Earth. That destruction is being committed at an ever-increasing rate by human societies such as our own that are more and more rationalizing and excusing their excesses in terms of religious doctrine.