October 25, 2009

A COTTONMOUTH'S COTTONY MOUTH
Last Monday was such a pretty fall day that Karen and I couldn't stay away from St. Catherine Creek National Wildlife Refuge's 24,442 acres of swamps and seasonally flooded fields along the Mississippi River just south of Natchez. This summer Karen has fished a lot there so the first thing we did was to go see if the rising river had flooded her favorite fishing hole.

The water was indeed over many of the refuge's roads and her fishing spot was flooded. We had to turn around at a spot where a thick-bodied, blackish snake was sprawled out sunning himself. You can see him at https://www.backyardnature.net/n/09/091025wm.jpg.

That's a venomous Cottonmouth or Water Moccasin, AGKISTRODON PISCIVORUS, common in swamps around here. The species is found throughout most of the US Southeast. Our snake was about 2-½ feet long and didn't seem at all concerned when I approached. The thick, black body, the head much wider than the slender neck, and the black mark behind the eye are about all you need to ID one of our Cottonmouths at a distance. Up close you also see a pit between the eye and nostril, which is a heat-sensing organ enabling the snake to locate prey in the dark, plus the eye's pupil is a vertical slit, like a cat's eye, instead of round. All of North America's poisonous snakes, including rattlesnakes and copperheads, are pit vipers with pits and vertical pupils, except for the coral snakes, which belong to a different family.

The green, confetti-like material on the snake's back is duckweed, indicating that the snake had just emerged from the water a few feet away. The species name "piscivorus" means "fish-eater" because Cottonmouths do catch and eat fish, their main fishing technique being cornering fish in shallow water. They also eat mammals, birds, amphibians, other snakes, small turtles and even small alligators.

You can see why Cottonmouths are called Cottonmouths at https://www.backyardnature.net/n/09/091025wn.jpg.

In that picture notice that between the two big fangs at the top of the mouth there's a pair of smaller ones forming. Also between the smaller ones there's yet another pair just beginning to take shape. Throughout any pit-viper's life new fangs always are being produced. On the average, fangs are replaced every sixty days or so. Though I've never seen it, I read that it's not unusual to find an old fang alongside a new one, a condition that lasts until the new fang is securely locked in place.

Also interesting in the picture is the tubelike affair at the bottom of the snake's mouth. That's the snake's breathing tube, or trachea. This design enables the snake to breathe while it's swallowing prey. Such breathing tubes are typical for snakes in general, not just pit vipers.

This picture also does a good job showing the Cottonmouth's "keeled scales." The keels are those slender little ridges running lengthwise down each scale. When you're identifying snakes with a field guide you're always being asked whether your unknown snake's scales are keeled or unkeeled because some snake groups have keeled scales and some don't. Cottonmouths have strongly keeled scales.

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A NEWLY ARRIVED CORMORANT
At https://www.backyardnature.net/n/09/091025co.jpg you see a Double-crested Cormorant, PHALACROCORAX AURITUS, just arrived for the winter. He perched on a limb not far from the Cottonmouth.

Back when I wrote for Aquaculture Magazine I profiled many catfish farms in Mississippi's Delta Region, and nearly all the farms' owners had awful things to say about Double-crested Cormorants. Cormorants find snatching catfish from shallow ponds to be easy food, and their sheer numbers usually overwhelmed any predator controls the farmers could devise.

The summer/winter distribution maps of most migrant bird species neatly show that the birds are one place during the summer and another in the winter. The Double-crested Cormorant's map is sloppier. You might be interested in comparing their winter map here   with their summer map showing where they nest here.

The summer map shows them breeding mostly in the north but also here and there in the southern states. This flexibility of behavior may prove very adaptive for them as global warming proceeds. It's documented that Double-crested Cormorants are increasing in numbers and expanding their distribution area.

Also flying around that day were some Anhingas, which look a lot like cormorants, except that Anhingas have sharp bills, while you can see that a cormorant's bill is rounded and hooked at the tip.

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FIRE ANT BODY-BRIDGES
As the swamp's waters rise, fire ant nests along the gravel roads are flooded, as shown at https://www.backyardnature.net/n/09/091025fi.jpg.

In that picture the dark brown mass at the right is the top of an almost submerged fire ant nest. The dark lines connecting the nest with the gravel road are ant-body bridges consisting of very many female worker ants linked together atop the water, enabling larger, winged ants to walk over them, as shown at https://www.backyardnature.net/n/09/091025fj.jpg.

I don't know whether the winged ones are male drones, female potential queens, or a mixture. If you look closely you can see that some workers carry white pupae in their mandibles.

Red Imported Fire Ants, which I assume these to be, are SOLENOPSIS INVICTA, native to South America. During my hermiting years near here my Newsletters were full of fire-ant stories, especially how they stung me as I gardened in fire-ant-infested ground. In fact, in taking the two above pictures I managed to get stung in about 20 places, but I was glad for the inoculation. My first sting many years ago resulted in awful, running, itching sores, but eventually I developed enough of an immunity to them that now they cause no more than a burning sensation that quickly passes, usually leaving no bump at all. I just need to be stung occasionally to keep up my immunity.

The University of Texas offers a fine fire ant FAQ at http://uts.cc.utexas.edu/~gilbert/research/fireants/faqans.html.

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VICEROYS GALORE
Hundreds and hundreds of orange and black butterflies flitted among weeds along the Refuge's narrow gravel roads and perched on the roads themselves. Karen drove slowly and did lots of zigzagging but it was impossible to miss them all. At first I thought they must be migrating Monarchs pausing on their journeys south, but when I got close to one I saw that it was smaller and darker than a Monarch and bore conspicuous black lines across its hindwings, which Monarchs don't have. You can what I saw, on a cocklebur leaf, at https://www.backyardnature.net/n/09/091025vr.jpg.

It's the Viceroy, LIMENITIS ARCHIPPUS, often cited as a classic example "Müllerian mimicry" because of its similarity to the Monarch. Müllerian mimicry is when two or more not-closely-related, "harmful" species (in this case they're both distasteful) share one or more common predators while mimicking one other's warning signals. Both Monarchs and Viceroys benefit from their predators knowing that orange-and-black butterflies tend to be too bitter to eat.

Müllerian mimicry is different from Batesian mimicry in that Batesian mimics are themselves "harmless" but imitate a dangerous species.

A Viceroy's wing undersides as he dines on raccoon poop composed mostly of reddish crawfish shell is seen at https://www.backyardnature.net/n/09/091025vs.jpg.

Why were so many Viceroys down in the swamp last Monday, and why did their favorite perch appear to be cocklebur plants? The Butterflies and Moths of North America website reports that Viceroy caterpillars eat leaves of willows, poplars and cottonwoods. The swamp had these in abundance so that may explain the sheer large numbers, but what about the cockleburs? The website also says that early in the season adult Viceroys feed on aphid honeydew, carrion, dung, and decaying fungi but later -- now -- feed more often on flowers in the Composite Family. Well, cockleburs were the most abundant members of the Composite Family along the roads that day, so I guess it all makes sense.

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CHECKERED-SKIPPER
The other day on an aster doing weed-service right next to my trailer a butterfly came along looking more ornate than usual, so I photographed him, as you can see at https://www.backyardnature.net/n/09/091025sk.jpg.

Bea up in Ontario tells me that EITHER it's the Common Checkered-Skipper, Pyrgus communis OR the White Checkered-Skipper, Pyrgus albescens. Both occur in this area. To assure me that she's taken the ID as far as a conscientious and honest insect-identifier dare take it she quoted from the Butterflies and Moths of North America website that the Common and the White species can be separated with confidence "only by dissection and examination of the male genitalia."

The two species share the same life history: Males patrol looking for females mostly in the afternoon. Females lay eggs singly on leaf buds and tops of leaves. Caterpillars make folded-leaf nests in which they live, feed, and hibernate.

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ADMIRING THE BLACK OAK
The local oaks are especially heavily laden with acorns this year because of the unusually rainy late summer and fall. A very common oak along upland ridges in this area is the Black Oak, QUERCUS VELUTINA, one of whose bug-eaten, deeply lobed, sharp-pointed leaves and smallish, blackish acorns are shown at https://www.backyardnature.net/n/09/091025qu.jpg.

The "velutina" in Black Oak's technical name refers to the "velvety" hairiness covering young stems and leaf undersurfaces. With a magnifying glass you can see that each hair consists of several sharp points radiating from a base. Such hairs are said to be "stellate," which means "starlike." You can see the "velutinous" covering of a Black Oak's stem tipped with two scaly, rusty buds from which leaves will emerge next year, and a larger terminal bud from which next year's stem will arise, at https://www.backyardnature.net/n/09/091025qv.jpg.

Where the entry lane passes beneath a large Black Oak here and there the ground is splotched orange. That's where cars have run over Black Oak acorns, which are bright orange inside, as you can see at https://www.backyardnature.net/n/09/091025qw.jpg.

The center acorn shows a worm tunnel. In fact, probably because of the rains, most acorns I cut across are either wormy or dead and black with fungus. The acorns' orange color is produced by tannin, which benefits the oak by making the acorns very bitter or even sickening when eaten raw. Tannin interferes with an animal's ability to metabolize protein. Some animals aren't bothered by tannin while others clearly prefer acorns from oak species containing less tannin in their acorns, such as members of the white oak group. Creatures that cache acorns, like jays and squirrels, may delay eating their acorns until groundwater has leached much of the tannin out. Indigenous Americans developed several acorn-leaching methods to make acorns more palatable.

Though Black Oaks are enormously important for the acorns they provide to wildlife, and for the excellent wood they produce, at one time they were most cherished for the tannin in their bark used by the leather tanning industry, and for the natural dyes that can be made from tannin. Being careful to not injure the tree by cutting to its cambium layer, I chipped a little outer bark from a Black Oak and exposed the orange, tannin-rich inner bark seen at https://www.backyardnature.net/n/09/091025qx.jpg.

Dye from Black Oak bark can be used to produce various earth tones -- add alum and you get a rich golden yellow, add chrome for brownish yellow, tin for lemon yellow, iron for olive brown, and more. You can read about these natural dyes in the free online Google Book that can be accessed by Goggling the keywords "dye plants and dyeing quercus velutina." The first listing on the resulting page should be the 1994 book "Dye Plants and Dyeing" by Margaret Cannon. Clicking on that link should load the page on Black Oak dyes. Paging down you should see color examples of dyes produced from Black Oak bark. The entry after "Black Oak" is for the Black Walnut and then "Blackberries," on and on. This is an excellent resource.

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THERE ARE HORNBEAMS...
In Kentucky I grew up calling them Blue Beeches but my first field guide said the better name was Ironwood, and nowadays field guides seem to have settled on the name Hornbeam. Whatever its common name, its technical name is CARPINUS CAROLINIANA. I was taught to place it in the Hazelnut Family, the Corylaceae, but nowadays most botanists regard it as a member of the Birch Family, the Betulaceae. You can see the tree's leaves bleached with sun-glare, and a fruiting head at https://www.backyardnature.net/n/09/091025hb.jpg.

That fruiting head is very curious, and distinctive. It consists of several three-lobed, down-slanted, modified leaves, or bracts, at the end of a branch. A close-up viewing two bracts from below is shown at https://www.backyardnature.net/n/09/091025hc.jpg.

There you can see that at the bracts' bases, where they attach to the stem, each bract bears a little oval thing, which is the tree's fruit, a nut. If you remember that birch fruit are tiny nuts attached to papery "wings" and clustered in dangling, spike-like heads, you'll recognize the relationship between Hornbeams and birches.

Hornbeams occur in the forest understory in moist, rich soil such as that at the bottoms of our bayous and are distributed nearly throughout North America's Eastern Forest biome.

The name "hornbeam" derives from the tree's hard wood, like hard cow-horn. The Old English term "beam" meant "tree," which is believable because it's a cognate with the German word for tree, "Baum." "Hard tree... "

The Hornbeam's trunk is distinctive, as seen at https://www.backyardnature.net/n/09/091025hd.jpg.

Note its smoothness, its slate-gray color, and its smooth ridges giving it a "muscular" look. Though Hornbeam wood is exceptionally hard, it's so difficult to work with because of that hardness and its twistiness that it isn't used that much. Traditionally one important use for it was as gear pegs in simple machines, especially windmills.

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AND HOPHORNBEAMS
At https://www.backyardnature.net/n/09/091025hh.jpg you see leaves and a fruiting head of the Hophornbeam, OSTRYA VIRGINIANA. Earlier this species also resided in the Hazelnut Family but now usually it's assigned to the Birch Family. You can see that though its leaves are very similar to the Hornbeam's its fruiting heads are different in that instead of downward slanted flat bracts they hold flatish bladders, like squashed Chinese lanterns. An open bladder is shown at https://www.backyardnature.net/n/09/091025hi.jpg.

The yellow-green item inside the bladder is the fruit, a nut. Therefore, the fruiting head actually is very similar to that of the Hornbeam's, except that the Hophornbeam's bracts surround the nut instead of simply spreading above it.

As with the Hornbeams, Hophornbeams are understory trees distributed throughout most of North America's Eastern Forest Biome. Because Hophornbeam leaves are so similar to Hornbeam leaves, students sometimes confuse the two species. The Hophornbeam's bark is pale ashy gray and flaky, however, very different from the smooth, slate-gray bark of the Hornbeam.

Where does the "hop" come from in Hophornbeam? If you've seen fruiting heads of the Hop vine used in brewing beer you already know. Hop heads are shown at http://www.geograph.org.uk/photo/549254.

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TRANSLUCENT LEAVES
I try not to get so involved identifying and analyzing things that I forget to notice how pretty they are. While I was down in the bayou photographing the above Hornbeam and Hophornbeam I looked up and saw what's at https://www.backyardnature.net/n/09/091025__.jpg.

After several days of heavy rain the air was so clean that sunlight exploded in leaves in a way seldom seen, creating a world of high-contrast black silhouettes and intricate translucency. Add to that the leaves' quivering in the wind, the wind's soughing sounds, the odor of a mellowing fall day...

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FROST ASTERS
Along gravel roads through the refuge's swampy areas the most eye-catching "weed" is the Frost Aster, SYMPHYOTRICHUM PILOSUM -- earlier known as Aster pilosus. A dense spray of its white flower-heads is at https://www.backyardnature.net/n/09/091025as.jpg.

Up close the plant reveals pleasing symmetries, its composite flower-heads each like perfect little daisies with white rays and yellow disk flowers, seen at https://www.backyardnature.net/n/09/091025au.jpg.

Yet closer you see that each yellow disk flower is a perfect flower all to itself close-packed in the composite flower's center, as shown at https://www.backyardnature.net/n/09/091025av.jpg.

Do you see how each disk flower's yellow corolla parts into five petal-like lobes? The brown things arising from the disk-flowers' centers are pollen-producing anthers. There are five anthers grown together by their edges into a cylinder around the style, which is the "neck" connecting the female ovary with its stigma, which is the fuzzy thing where pollen grains land and germinate.

At https://www.backyardnature.net/n/09/091025at.jpg you see that below the composite head there are sharp-pointed, green-tipped involucral bracts or phyllaries with incurved margins -- something important to notice when identifying asters, for there's a lot of closely related, look-alike species.

Frost Asters are among the most abundant of all our asters, and are found in rather dry and open places, often in sandy soil as along gravel roads.

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LONGLEAF WOODOATS
If you go into the woods where a small opening lets in a little light and the soil is rich and fairly moist, around here you're bound to see the grass shown at https://www.backyardnature.net/n/09/091025ch.jpg.

One common name for this is Longleaf Woodoats. It's CHASMANTHIUM SESSILIFLORUM, common throughout the US Southeast, though it doesn't make it as far north as my boyhood home in Kentucky. A close-up of its flowers is at https://www.backyardnature.net/n/09/091025ci.jpg.

It's unusual for a grass's flowers to be twisted to one side like these. The broad, yellowish, disc-shaped things subtended by sharp-pointed, pinkish "bracts" -- the lemmas and paleas -- are simple, dry fruits, or grains, technically known as caryopses. It's also unusual for caryopses to be so exposed. I'm guessing that both the flowers' twistiness and the caryopses' exposed nature encourage birds to snatch them away, in the process dropping some of them, thus sowing them in new places.

Last year I introduced you to Indian Woodoats, which is similarly common and graceful. It belongs to the same genus. You can review what that species looks like at https://www.backyardnature.net/n/h/woodoats.htm.

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LOTS OF DUCKWEED
Nowadays much of the Refuge's standing water is carpeted with green duckweed, as you can see in the picture of the smiling Alligator surrounded by Buttonbushes and his back sprinkled with duckweed at https://www.backyardnature.net/n/09/091025li.jpg.

Duckweeds -- genus Lemna in the Duckweed Family, the Lemnaceae -- consist of tiny, flat, usually oval fronds typically floating free on the water's surface, dangling below one or more pale roots which do not root in the mud. Flowers are seldom seen; reproduction is mostly by budding. Some fronds cover my fingertip at https://www.backyardnature.net/n/09/091025lj.jpg.

The Flora of North America lists nine duckweed species for our continent. They can be hard to distinguish so I'm only somewhat sure that what's on my finger is LEMNA MINUTA. I'm calling it that because the fronds bear only a single obscure vein.

It feels good to see all that duckweed, to think about it photosynthesizing so much oxygen for us all, and providing so much good food for wildlife, especially waterfowl.

Nowadays duckweeds are being grown in ponds of potentially dangerous sewage and wastewater. The duckweeds thrive on nutrients released in the water but do not normally take toxins into their own bodies, so they can be skimmed off and fed to livestock, thus recycling nutrients that otherwise would be lost. There's much more about this exciting duckweed use at http://www.mobot.org/jwcross/duckweed/practical_duckweed.htm.

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BROAD BEECH FERN
It's an especially good time of the year to be paying attention to ferns because now their spore-producing "fruit dots" or sori are well developed, and sori often are as important in fern identification as flowers are in wildflower IDing. A fern drawing my attention this week down in the bayou, however, didn't need to show its sori for me to know it because its frond was so distinctive -- like a deeply incised triangle held aloft on a slender, 15-inch stem, seen at https://www.backyardnature.net/n/09/091025bb.jpg.

That's the Broad Beech Fern, PHEGOPTERIS HEXAGONOPTERA, typical of rich, moist soil just like we have down in our steep-walled bayous. Broad Beech Ferns occur throughout eastern North America except in the northernmost parts. You can see its sori at https://www.backyardnature.net/n/09/091025bc.jpg.

These sori are different from most of those we've looked at lately in that they are "naked" -- aren't associated with cellophane-like indusia which cover part of the sori of many fern species. Here the microscopic, baglike affairs that open to release spores, the sporangia, are simply clustered on the fronds' undersides with no indusia at all.

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RELIGION, ATHEISM & THE MIDDLE PATH
The other day an interview on National Public Radio disclosed how the atheist movement in the US has fractured into fundamentalists and progressives. The fundamentalists aggressively ridicule and attack the beliefs of religious people while progressives see this as counterproductive, recognizing history's lesson that persecution draws attention to religious groups, causing more people to join them.

It sounds about right for the atheist movement to be breaking apart, for Nature shows that all things that become big and complex, even philosophical movements, fracture into smaller, often competing parts, unless they go extinct. The Tree of Life is the model for how it's done: There's a single, simple beginning, or trunk, that branches, and then those branches branch, and those branches branch, on and on. Atheism, then, having grown enough to be a large, complex movement, must fracture.

Both atheism and religiosity are positions taken with regard to humanity's spiritual condition, and they are both extreme positions. Atheism is extreme because its advocates behold the Universe's enormity, complexity and mystery, yet deny that any kind of Creative Impulse is responsible and worthy of reverence, or at least recognition. Religiosity is just as extreme because it requires its adherents to accept a belief system or "faith" off the shelf, prepackaged by someone else, and blindly believe in it with heart and soul.

A Middle Path is available between these two extremes. The spiritual Middle Path requires no priests, no sacred texts, no rites, no tithing or even a name. It is something between a mood and an understanding that spontaneously arises within each of us when we reflect on the nature of Nature, and allow our insights and behavior to evolve in harmony with that ever-more-inspiriting mood-understanding. Along this Nature-guided Middle Path "ethical behavior," enhanced sensitivity to the rest of Creation, and reverence for the Creator arise spontaneously.

It's beautiful to follow the spiritual Middle Path. It's beautiful to go forward blossoming just as the Earthly biosphere keeps blossoming from its original single spark of life, just as the Tree of Life continues branching and rebranching toward ever more gorgeous, intricate, vibrant diversity.

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Best wishes to all Newsletter readers,

Jim