from the woods near Natchez, Mississippi, USA
February 10, 2002
SNAIL SHELLS IN THE LOESS
You simply can't walk in the bayous here without finding fossils. Before I tell you about them, remember that in this area a bayou is a special kind of deep, steep-walled ravine or gully, not the broad, dead-water swamps or tidal basins called bayous in Louisiana.
Our most abundant bayou fossils are the white snail shells found embedded in the loess forming the bayous' almost-vertical walls. At my loess site at http://www.earthfoot.org/loess/snails.htm you can see a picture of such shells in loess here at Laurel Hill. If you are fuzzy about what loess is, go to http://www.earthfoot.org/loess/geology.html
Early in the 20th Century similar loess-embedded snail shells were used by geologists to figure out when our loess was deposited. A few decades later snail shells just like ours were removed from a roadcut through loess at Vicksburg 70 miles north of here and their age was determined using Carbon-14 dating. Shells toward the top of the roadcut were found to be 17,850 years old, give or take 380 years. Shells from the middle of the cut were placed at 19,250 years old, give or take 350 years, and shells at the bottom of the loess registered at 25,300 years old, give or take 1,000 years.
Of course it makes sense that the deeper you go in the loess, the older the shells would be, since what's on bottom is what was deposited first. I provide a brief explanation of how Carbon-14 dating works at http://www.earthfoot.org/loess/c14.htm These dates -- between 17,850 and 25,300 years ago -- marked the end of the last Ice Age. At that time the ice sheet north of the Ohio River was melting, producing enormous quantities of meltwater that passed by our present location on its journey to the Gulf of Mexico. The Mississippi River then was a vast "braided stream" much larger than the present river. Its water gushed over a vast plain bearing unfathomable amounts of gravel, sand and silt.
As now, during winters less water flowed because precipitation north of here was frozen. When water was relatively low, large mudflats and many islands appeared between the big river's widely separated shores. It's theorized that mud coating these emergent land masses would dry, then strong westerly winds would stir up silt particles from the dried mud and carry them as dust. This dust would then drop on the Mississippi's bluffs and highlands immediately to the east -- where we are now -- and of course that deposited dust became our loess. It was a slow process, with thousands of years of dust deposition leaving only a few hundred feet of loess.
Life atop the accumulating loess went on as always. And when snails died their shells remained as stonelike fossils. The 25,000-year old shells pried from Laurel Hill's loess today look just like last year's bleached ones atop the soil.
There are other fossils in our bayous, even ones much more interesting than these, but I'll wait for another time to tell you about them.
For two days and nights this week the temperature remained just a bit above freezing and it rained almost incessantly. This bone-penetrating chill was surely harder on the birds and other creatures than me.
On Friday for the first time in a long time morning sunlight flooded in from the west. I sat at my campfire feeling its glow on my face and the birds were like so many elves among the tree limbs and Spanish Moss above me. I particularly noticed American Goldfinches, Carolina Chickadees and Myrtle Warblers working along the big branches pecking into the bark. They'd do this a while, then perch in the warming sunlight as if digesting between meals.
My binoculars showed what they were doing. In my Newsletter of January 20 I told you about our outbreak of Giant Bark Aphids. The outbreak continues and they provide snacks for birds working along big tree branches. These aphids suck the tree's sweet sap until they are BB-sized and they must taste like candy to any critter with taste buds sensitive to sweetness.
Despite the birds' depredations among the aphids, the aphids are more than holding their own. Here and there on every Pecan-tree limb and many oak branches there are black splotches looking at first like soot. But close-up the sootiness shows vast gatherings of legs and plump bodies. I fear the aphids may cause infections on these trees, and stunt their growth.
I wonder if some environmental component here has grown so far out of whack that this aphid outburst is a consequence? The way Natchez's paper mill smells 12 miles away when they release their pollution deep in the night when we aren't supposed to notice or care, it could well be something like that.
I'm not alone in watching goldfinches feed. My cousin Miles in Kentucky writes about the "6-holer" feeder outside his window just an arm-length away, with all the perches occupied by finches, with others waiting their turn. Jean Farrar of Natchez tells me she's having a hard time keeping her thistle-seed feeder filled, and she makes the sharp observations that "Last spring before they left, they fed in a frenzy for about three or four days and then they were gone. The city dwellers are just beginning to get their golden feathers."
Jean also tells me that someone at Cornell University in New York told her that "Goldfinch did not migrate from this area."
I replied that they do indeed migrate. I remember that in Kentucky they are present year round, but down here you just never see one during the summer. I confirmed this by reviewing a goldfinch distribution map, one of which you can view at http://188.8.131.52/portfolios/h/horner_e/njcm/distr ibution_maps/amgold.gif
That colorful map clearly shows that during the winter goldfinches are present in Natchez and all through the Deep South, including all of Florida and Texas (and I've seen them as far south as Veracruz in Mexico), but that during the summer they are absent here. Likewise, they are absent from vast stretches of Canada during the winter, but present during the summer. Obviously many American Goldfinches do migrate considerably.
Nonetheless I was astonished to see at a US Government "Ask A Scientist" site that the expert said "Most American goldfinch populations are non-migratory or only migrate very short distances in no particular direction."
I suspect that we are all right. Probably the goldfinches at Cornell don't migrate, or migrate only haphazardly, but our Natchez ones most certainly do, and those visiting Florida, Texas, northern Mexico and northern Canada migrate a good bit. I also suspect that many goldfinch populations are like certain flocks of Canada Geese who are fed so lavishly by city folks that they hang around their feeding spots year round. Today in many places Canada Geese are permanent residents where 50 years ago they were strictly migratory.
I enjoy these bird-feeder observations so anyone who has one feel free to drop me a note at email@example.com
TRILLING PINE WARBLERS
For a couple of weeks the main birding sign that spring is coming is that each morning the Pine Warblers have been trilling. "Trilling" is their song. It's a lot like the Chipping Sparrow's song, but slower, lower, softer, not at all mechanical like the Chipping Sparrow's. He trills with a Southern drawl. Today the Pine Warbler near my trailer has sung longer than usual, undoubtedly because he is feeling extra spring hormones.
Pine Warblers are little yellow birds with slender, insect-eating beaks. They are present here year-round, but they are only summer residents in most of the rest of eastern North America. They are found mostly in mature pine forests, pine barrens and open mixed woodlands, the latter forest type being what we have here.
I like watching this Pine Warbler trill, for when he calls he raises his head as if looking at the sky and he trembles his wings, making it appear to be a heartfelt calling. Something there is in any display of sincerity that always pleases me. You can see Pine Warblers and hear their pleasant trilling at http://www.mbr-pwrc.usgs.gov/id/framlst/i6710id.html
FLOWERING WINGED ELMS
In the forest the most profound sign of spring is the flowering of the Winged Elms, ULMUS ALATA. This Sunday morning as I biked across the field to the Hunters' Camp a certain medium-sized tree at the woods' edge, with the sun behind it, glowed pale reddish-brown as if its branches were lit with thousands of tiny, flickering candles. Sunlight was exploding inside thumbnail-size clusters of flowers. In fact, most of the flowers had already been fertilized so that fuzzy, flat elm fruits just a bit larger than this O were evident. You can see Winged Elm flowers at http://www.csdl.tamu.edu/FLORA/fa01/fa01053.jpg
In that picture only the bottommost flower shows an emerging elm fruit -- our flowers are more advanced into spring than those in this picture. Notice how the edges of that fruit are densely covered with long, silvery fuzz. This is one way to distinguish Winged Elms from American Elms and Slippery Elms, the other two elms in our area. The fruits of the American Elm have only very short hairs along the edge, not at all woolly as in this picture, and Slippery Elm fruit-edges are completely hairless. Winged Elms often have winglike corky ridges on their branches, making the tree easy to identify, but many individuals do not show these corky wings.
So, here's a native tree in full flower, even before leaves have come onto its branches. I'm sure the same is true of the Red Maples in the swamps between here and the Mississippi River.
ON THE BEAUTY OF HUNKERING DOWN
Much of this week has been both cold and wet -- a painful combination in an unheated trailer. Sometimes I had to crawl into my sleeping bag just to keep it together. In times like that, you can't be very creative. You just have to "hunker down" and wait for time to pass. I am glad to have had these days. Let me explain.
First of all, the other day I was discussing this matter via email with my friend Rengyu in Bangladesh. I said that once such a trial is over, it's as if you have acquired a new measure of inner strength. Rengyu could relate to what I was saying, especially because at that time he was fasting during Ramadan. By undergoing physical hardships and denying my natural instincts to flee to warmth, and by stubbornly following a secret star even when from the outside what's going on looks appallingly dreary, I gain something I can't quite explain to someone who doesn't already understand, but I know that in the end I have acquired something internally of great value.
Second, last week when I described the effect on me of sniffing a Yellow Jessamine blossom, the point was less that Yellow Jessamine really smells good than that by exercising self control most of the time I am priming myself for later forays into a realm of sensuality that no debauched hamburger eater can imagine. When these cold days finally pass and cascades of golden sunlight gush over me, who do you think will FEEL the return of spring more acutely than I? One reason I live the way I do is simply because I love to FEEL alive, strong, hungry, aggressive... I like to feed my senses. There have been times in my life when that meant eating a lot, other times when it meant being with special kinds of women. Right now it means priming myself so that the odor of Yellow Jessamine just knocks my pants off.
A third reason is this: I am convinced that there is no greater Earthly "sin" than to needlessly abuse and endanger the living system -- the ecosystem -- with which the Creator has graced this good Earth. And I know that when I flip a switch to warm my feet I am ordering electricity to be produced, which increases greenhouse gasses and radioactive wastes. I will not belabor the point. Every human appetite translates into environmental destruction, and it is up to each of us to identify for ourselves how much destruction we wish to be responsible for.
I have other reasons for living as I do, but by now you can glimpse the tendency of my convictions, and that is enough for now.