October 14, 2012
CLOSE LOOK AT A TURKEY FEATHER
On the ground around here you find plenty of what's shown at http://www.backyardnature.net/n/12/121014fe.jpg.
That's a feather from a Wild Turkey, which are abundant in the valley of the Dry Frio River. Most mornings when I jog at dawn flocks of more than twenty turkeys watch me from the fields as I run by. I live on Turkey Trot Road. Those feathers are everywhere.
As with everything in life, once you start studying something -- something even as simple as a feather -- you find that there's a lot to know about it.
For example, feather tips can be pointed, rounded or squared. Our turkey feather is one of the minority of squared ones. Birds grow two kinds of feathers. The "contour" or "vaned" type covers the bird's body, then beneath the contour feathers lie down feathers. The feather in the picture is a contour type. Down feathers are smaller and fluffier.
The stiff, sharp "stem" by which the feather in the picture is held is the quill, or calamus. The stiff "midrib" running up the feather's center is variously called the rachis, shaft or stem. The main, flat, often pigmented part of the feather is known as the vane. The vanes of most feathers, like ours, have one side narrower than the other. The vane's narrow side is known as the outer vane and of course the wider side is the inner vane. The lowest and usually the widest part of the inner vane is often recognized as the "up-curved edge."
Each semi-stiff little item arising from the rachis and meshing with its neighbor to form the flat vane is a barb. If you put our feather right up to your eye or use a low-power hand lens, and have a good light behind the feather, you can see what's shown at http://www.backyardnature.net/n/12/121014ff.jpg.
The dark lines running diagonally across the image are barbs. You can see that each barb is itself like a tiny feather, in that soft, feathery items arise from its sides. These feathery items are barbules. Notice that barbule tips on adjacent barbs overlap one another. Just by looking at how the barbules are arranged you can guess that the barbules of neighboring barbs somehow stick together, maybe in a Velcro-like manner.
It happens that a fine microscope with a camera adapter is available to me, so I've been able to take an even closer look at what's going on with these sticking-together barbs and barbules. Using the microscope's weakest magnification I looked at a barb in our turkey feather in which the barbules on one of its side were attached to its neighbor's barbules, but the barbules on the other hung in the air because I'd pulled the barbs apart there. That image is at http://www.backyardnature.net/n/12/121014fd.jpg.
Notice that the downward-directed barbules of the silhouetted barb at the top, left partially overlap the horizontal barbules of the silhouetted barb at the bottom. Also, look at how the half of each barbule nearest the barb appears to be stiffer and more neatly organized parallel with its neighboring barbule than the barbule's outer end. Also, in the lower, right corner of the picture notice how the barbules' outer end bears tiny, spine-like items. You can see the spine-like items at a higher magnification at http://www.backyardnature.net/n/12/121014fc.jpg.
These spine-like items are "hooks," so already you can guess that barbules from neighboring barbs stick together because hooks on the barbules latch onto the barbules of its neighboring barb. In the last picture, notice that many of the hooks really are hooked.
What a world a feather is!
MONARCH BUTTERFLIES MIGRATING THROUGH TEXAS
Friday at dusk Malle and I were picking pecans from trees along the little Dry Frio River. When it got so dark we could hardly see the clusters of nuts on the branches we noticed a certain fluttering above our heads, which turned out to be Monarch butterflies. I'd not seen a single Monarch in this area since I've been here but suddenly here were about a dozen flying in and out of the tree's deep shadows as if checking things out.
Monarchs occur in Texas only during their migrations, for their summer distribution area lies well to the north of us. These were definitely migrants who clustered in a way I've only seen them do in their wintering grounds in the highlands of central Mexico. You can see several clustering in a flash-enhanced picture at http://www.backyardnature.net/n/12/121014mo.jpg.
It turns out that Uvalde County lies in the center of the Monarchs' Central Flyway and that historically the peak of their migration here occurs on about October 18th. These were seen on October 12th. An excellent page with many links to Monarch matters, and maps showing Texas' flyways and when the migration peaks occur is at http://www.texasento.net/fall_peak.htm.
An online article about the decline of Monarchs and the problems they face is online at http://www.sciencedaily.com/releases/2012/03/120321172210.htm.
In that 2012 story it's stated that this year Monarchs covered about 7.14 acres (2.9 hectares) of forest in their Mexican breeding grounds compared to 9.9 acres (4.0 hectares) last year, continuing a long-term downward trend in the Monarch population since official surveys began in 1994.
I wonder if we will be seeing these wonderful butterflies much longer?
A while back a White-winged Dove landed on my host's balcony next to his birdfeeder, enabling the fine picture shown at http://www.backyardnature.net/n/12/121014ww.jpg.
In the Yucatan and many other places we've been in Mexico White-winged Doves were the most common dove species, often abundant in arid-zone weedy fields and around small villages. When I arrived here in August I was surprised to see that they're common in this area, too. But then this week when the above picture was sent to me I realized that I'd not been seeing White-wings lately. Nowadays you just see very many Eurasian Collared Doves conspicuously perching on electrical lines. Have our White-winged Doves "gone south."
But then I saw one White-winged Dove flying low and fast over the cabin, very unlike in August when small flocks often lolled about in treetops and in fields. Now I remembered how back in Kentucky and Mississippi the Mourning Doves got much more nervous and suspicious in the fall, during hunting season, so maybe that was what happened with our White-wings.
In fact, we're about 35 miles north of Texas' "Special White-winged Dove Hunting Area," in which hunting season take place during parts of September, October, December and January. Therefore, White-winged Doves appear to be permanent residents here, and at this time of year they have good reason to maintain a low profile.
Historically White-winged Doves where found only very spottily in Texas, including some small, dispersed groups here on the southern border of the Edwards Plateau. Mainly they lived in the Lower Rio Grande Valley, Texas's southernmost tip, a good distance south of here. However, during the 1980s hard freezes in the Lower Rio Grande Valley destroyed the area's citrus groves, which had become prime nesting grounds for the species. It's supposed that the loss of nesting opportunities there caused a vigorous expansion of the bird's distribution northward through much of Texas and into other southern states, the northward expansion possibly nudged along by the general effects of global warming.
Whatever the case, six weeks ago peacefully preening and cooing White-winged Doves were common sights here but now they're not.
By the way, Eurasian Collared Doves are larger and appear to be more aggressive than White-winged Doves, but the arrival of that species is so recent that investigators haven't figured out yet whether Eurasian Collared Doves are displacing White-wings.
Texas dove hunters chatting in online hunting forums seem to have arrived at this consensus, though: That several years ago in Texas White-winged Doves drove out many of the traditionally hunted Mourning Doves, and now Eurasian Collared Doves are displacing the White-wings.
Back when I was traveling the US Desert Southwest for my online book at http://www.backyardnature.net/desert/ I kept running into large, black beetles walking across the sand or dust with their rear ends much elevated above their heads. When disturbed they would raise their rear ends even higher. Picking some up I quickly figured out why high rear ends were so important to them: From their rear ends they could exude, even squirt, secretions so stinky that few predators would want to deal with it. Therefore, this week when a high-rear-ended black beetle appeared beneath a loose tile in the bathroom I knew what he was: A darkling beetle, genus ELEODES. You can see him at http://www.backyardnature.net/n/12/121014bt.jpg.
Saying that he's a darkling beetle really isn't saying much, since that name is applied to several genera embracing over 1400 species within the Darkling Beetle Family, the Tenebrionidae. Darkling beetles are also called stinkbugs, though that name is used for many unrelated insects capable of stinking. Also they're called clown beetles because they do look funny walking with their rear ends held so high. And they're called pinacate beetles, the word "pinacate" deriving from the Aztec term pinacatl meaning "black beetle."
Despite knowing that so many look-alike darkling beetles exist I sent our photograph to volunteer identifier Bea in Ontario, since sometimes she figures out even the most obscure things. However, this time she replied pointing out that "Within the state of Texas a total of 31 species are known to occur... I checked each and every one of the species and although some can be ruled out because they have a rounded abdomen and yours looks pointy, and yours also looks smooth instead of having ridges on the forewings, there are still too many it could be... "
I read that grasshopper mice have been observed getting around the stinking rear ends by jamming beetle behinds into the sand and eating the insect head first. Other predators somehow able to deal with the odor include burrowing owls, Loggerhead Shrikes and skunks.
Notwithstanding all this talk of stinking rear ends, I sniffed our beetle's behind and didn't smell a thing. I do recall, however, some magnificent stinks caused by beetles encountered in more natural situations, and I've been squirted with the stink, too. I read that some of the larger desert species can spurt their juice up to 20 inches (50cm).
In the thin, dry soil atop the limestone hill in front of the cabin the vegetation thins out so that you almost get what back in the mountains of Kentucky we called a "bald" -- a spot so exposed to the elements that only a few highly specialized plants can grow there. In such places often you find rare and unusual organisms, and that's the only place I've seen the much branched, five-ft-high (1.5m) shrub whose current flowering is being admired by my Estonian lady-friend Malle at http://www.backyardnature.net/n/12/121014ey.jpg.
This is an unusual-looking bush, with narrow, three-inch-long (7.5cm), pinnately compound leaves with gland-dotted, aromatic, resinous leaflets and flowers, and the widely spaced leaflets held stiffly at right angles to their rachis, as shown at http://www.backyardnature.net/n/12/121014ez.jpg.
The bushes' fruits are just beginning to mature, and you can see that they are plump, stubby, legume-type fruits containing 2-4 beans at http://www.backyardnature.net/n/12/121014ew.jpg.
Alternate, pinnately compound leaves and legume-type fruits are good field marks for members of the Bean Family, so when you want to confirm that that's what you have by examining the flowers, you might get a bit confused. That's because this bush's blossoms don't display the usual Bean-Family "papilionaceous" structure -- the "butterfly-like," bilaterally symmetrical corolla composed of standard, wings and keel, as described at http://www.backyardnature.net/fl_beans.htm.
Our hilltop bush's flowers are scarcely at all papilionaceous, having petals of nearly equal length, as you can see at http://www.backyardnature.net/n/12/121014ex.jpg.
The bush is called Texas Kidneywood, Bee-Brush and Vara Dulce. It's EYSENHARDTIA TEXANA, native to dry, rocky, calcareous (limestone) soils of arid northern Mexico and in the US only found in south-central and southwestern Texas.
This is a fine little tree, its numerous, aromatic flowers attracting a wide variety of pollinators, and its twigs and leaves regarded as very palatable for deer and goats. Web pages describing the bush's uses copy from one another the fact that "the wood has been used for dyes and is fluorescent in water," but none tells what color the dye is or expands on its fluorescent wood.
In evolutionary terms, I'd imagined that Kidneywood's non-papilionaceous blossoms indicated that the genus Eysenhardtia might be an ancestral genus in the Bean Family, one arisen before more modern genera developed their now-characteristic papilionaceous flower structure. However, the gene sequencers have looked at that very question. In a 2004 paper in the American Journal of Botany online at http://www.amjbot.org/content/91/8/1219.full, McMahon and Hufford conclude that that's not the case. The "primitive condition" for the Bean Family is to have papilionaceous flowers. Kidneywood's almost radially symmetrical flowers are a relatively recent expression of the family.
On the little Dry Frio River's streambed where sandbars and low-lying deposits of cobbles and gravel usually remain dry and soilless, but sometimes are underwater a few days as floodwaters rage over them, there are dense thickets of robust, soft-woody, much branching shrubs ten feet high and taller (3m). Nowadays each of these plants bears thousands of tiny white flowers, so many that from a distance the plants look white, as seen at http://www.backyardnature.net/n/12/121014bc.jpg.
Up close you can see that the flowers are grouped in heads typical of the huge Composite or Sunflower Family, and that the leaves are short, slender affairs, as shown at http://www.backyardnature.net/n/12/121014bd.jpg.
In thickets with many bushes it's easy to see that there are two kinds of these plants, one presenting a slightly more greenish overall appearance, and the other more brightly white, as seen at http://www.backyardnature.net/n/12/121014bf.jpg.
The darker plant on the left in that picture is the male bearing only male flowers, while the whiter-flowered female is on the right. A close-up of heads of male flowers is at http://www.backyardnature.net/n/12/121014be.jpg.
In that picture the slender items projecting from the heads' tops are cylinders formed by five anthers joined at their margins. Also notice that there are no petal-like ray flowers. A close-up of heads of female flowers can be compared at http://www.backyardnature.net/n/12/121014bg.jpg.
The white fuzz extending from the urn-shaped involucres is composed of pappus hairs, a pappus being the collection of hairs or other items atop the ovary or future achene-type fruit. Once the achene is mature the pappus will serve as a parachute helping the fruits disseminate on the wind.
These eye-catching, vigorous plants are known by several English names, such as Roosevelt Weed, New Deal Weed, Poverty Weed, False Willow, Dry-land Willow, and Jara Dulce. It's BACCHARIS NEGLECTA, found mostly in arid northern Mexico but also in most of southern and southeastern Texas, and small parts of extreme southern Arizona and New Mexico.
There's a story behind those common names evoking Roosevelt, the New Deal and Poverty. During Roosevelt's presidency as the US was trying to recover from its Great Depression and Dust Bowl days our Baccharis neglecta was planted in many areas in an attempt to revegetate the severely drought-damaged soil. However, the very same aggressiveness and adaptability that made it useful then are causing problems now, because in many areas the plant has become an aggressive invader of rangeland and disturbed sites. It forms dense stands and when burned or cut quickly resprouts.
In the US Deep South, mainly along the Coastal Plain, a similar but not as woody and tall species, Baccharis halimifolia, similarly aggressively invades abandoned fields and forests that have been clearcut.
The genus Baccharis is mostly centered in tropical and warm-temperate South America. Up to 450 species are thought to exist, of which 21 are listed in the online Flora of North America.
BALDCYPRESS ALONG THE DRY FRIO RIVER
I've always associated Baldcypress, TAXODIUM DISTICHUM, with swamps, bayous and big, slow-moving rivers, so before arriving in arid southwestern Texas I was surprised to read on a Texas A&M webpage that Baldcypresses "... can be found along river beds and wet areas of the Edwards Plateau and South Texas Plains." We're exactly where the Edwards Plateau meets the Coastal Plain, so Baldcypresses should be here. And they are, as shown at http://www.backyardnature.net/n/12/121014tx.jpg.
That picture shows a Baldcypress' cone-type fruit at the tip of a branch from which also arise drooping branchlets on which many green, slender leaves grow. In other words, the "green feathers" in the picture are not dangling compound leaves, but rather branches bearing many short, slender, needlelike leaves.
Though the literature is clear about Baldcypress being native to this area's river beds, I'm told that the trees along the little Dry Frio River behind the cabin were planted some years ago, and that naturally occurring Baldcypresses aren't found here. I suspect that that's true, the tree's wonderful wood having doomed the species to extermination in this area by loggers wanting the wood. I also hear that along other local rivers some very large, old Baldcypresses remain.
Baldcypress' taxonomy has always been a mess. Nowadays what we used to call the Pondcypress is lumped into the Baldcypress species. The online Flora of North America recognizes three varieties, with the species distributed from North America through Mexico into Guatemala. In Texas other names used for the species include Black Cypress, White Cypress, Yellow Cypress, Red Cypress, Gulf Cypress, Southern Cypress, Swamp Cypress and Sabino-Tree.
Nowadays throughout much of North America goldenrods are, or recently were, putting on a show with their golden arrays of composite flowers. I'd wondered whether there might be goldenrods here in arid southwestern Texas, so I was tickled during my first walk along the little Dry Frio River behind the cabin to see some. The instant I saw them, however, I figured that there was something special about them. First, they appeared only beside, and sometimes inside, the Dry Frio's waters. Second, their arrays of yellow flowers were particularly long and slender. Otherwise, the plants looked very much like the common and often weedy Tall and Canada Goldenrods back in Kentucky and Mississippi. You can see our riverside goldenrods at http://www.backyardnature.net/n/12/121014sd.jpg.
A close-up of some flower heads shows not only the typical goldenrod appearance but also the stem, or rachis, from which the heads arise. Notice that the rachis is unusually soft-hairy at http://www.backyardnature.net/n/12/121014se.jpg.
A leaf from mid-stem is three-veined like the leaves of Tall and Canada Goldenrods, but its margins are only very slightly toothed, and the blade is very narrow and hairy, as you can see at http://www.backyardnature.net/n/12/121014sf.jpg.
The abundant soft-hairiness is something special, so I photographed a leaf's undersurface, which you can see at http://www.backyardnature.net/n/12/121014sg.jpg.
Fortunately the online Flora of North America -- though it's unfinished and many families are yet to be treated -- does indeed describe all 77 goldenrod species (genus Solidago) occurring in North America. There our streamside plants keyed out to Julia's Goldenrod, SOLIDAGO JULIAE, a species not recognized as an independent species until 1989. Before then it was considered a variety of the common Canada Goldenrod, Solidago canadensis.
Flora of North America describes Julia's Goldenrod as occurring in wet soil along streams and lake edges, grasslands, and oak and oak-pine woods. It's found in arid northern Mexico, and enters Texas in the Trans-Pecos region (far western Texas) and the Edwards Plateau, of which we're at the base.
So, this is a wonderful find, an endemic species adapted for exactly the kind of habitat it's occupying here, and looking exactly as it's supposed to look.
Nowadays along roadsides as well as in thin soil atop limestone ledges along the little Dry Frio River, and lots of habitats in between, there's a super-abundant, knee-high, annual wildflower/weed whose many branches and leaves are so slender that the little yellow flowers at branch ends sometimes look as if they're suspended in thin air. Along the roads the effect is of a yellow-tinged gauziness. You can get a hint of the visual affect at http://www.backyardnature.net/n/12/121014gu.jpg.
Up close you see that the flowers are typical of the enormous Composite or Sunflower Family, with ray flowers looking like petals and disk flowers clustered in the head's center, at http://www.backyardnature.net/n/12/121014gv.jpg.
This is Texas Snakeweed, also known as Texas Broomweed, Annual Broomweed, Matchbush, Matchweed and Kindling Weed. It's GUTIERREZIA TEXANA, found in much of northern Mexico and the US south-central states. The various names alluding to firemaking allude to the fact that later in the year when the stems are frost-killed and dry, you can grab a handful of stalks and twist them together to make a torch that burns when you set fire to it. You can do that with many grasses and other plants as well, but Texas Snakeweed leaves and stems contain a substance that burns exceptionally well. Some say substance is like turpentine, but I can't see it. It is indeed smelly and leaves the fingers gummy, though. In the old days pioneers, impressed with the medicinal qualities of turpentine, served up teas of Texas Snakeweed as cold remedies.
In thin, dry soil on the upper slopes of the limestone hill in front of the cabin there's a perennial clumpgrass producing smallish tufts of grass from which arise slender waist-high inflorescences looking far too tall for such a small grass. The inflorescences catch the eye because the look like fuzzy eyebrows oddly stuck onto the very slender stems, or rachises. You can see what this looks like at http://www.backyardnature.net/n/12/121014bu.jpg.
A close-up of one of the eyebrows is at http://www.backyardnature.net/n/12/121014bv.jpg.
This grass is often known as Eyebrow Grass, but more formal literature usually refers to it as Tall Grama. It's BOUTELOUA PECTINATA. Besides the tall inflorescences arising from such meager herbage, another field mark for the species is how each eyebrow, or inflorescence branch, ends with a flowerless, or "naked," projection. That spine-like projection makes Eyebrow Grass a little undesirable to grazing cattle and deer. That may be the point of the point: To keep critters from eating it.
Eyebrow Grass is endemic to Texas and maybe a tiny part of Oklahoma. Actually, some authorities regard this species as a mere variety of the much more widely distributed Hairy Grama, Bouteloua hirsuta, but some who have the most field experience with the species insist that it's a distinct species.
We looked at another grama grass -- a member of the genus Bouteloua -- in our September 30 newsletter. That was Sideoats Grama, Bouteloua curtipendula, Texas's state grass. Bouteloua is a native American genus its center of diversification apparently in Mexico. About 24 species are recognized.
Grama grasses are "C4 grasses," which means that during the evolution of the Grass Family a certain ancestor blundered upon a more efficient photosynthetic pathway than the one usually taught in school, and which most plants use. This innovation, maybe a mutation, enables C4 grasses to capture carbon dioxide from the air more efficiently, resulting in less water being lost through transpiration. Thus the genus Bouteloua has a definite physiological advantage over other plants not benefiting from the C4 pathway.
FEATURED ESSAYS FROM THE PAST:
"Running Toward Alpha Centauri," from the March 2, 2007 Newsletter, at http://www.backyardnature.net/n/p/070302.htm.
"Running in Starlight" from the October 24, 2010 Newsletter, at http://www.backyardnature.net/n/p/101024.htm.
Best wishes to all Newsletter readers,
All previous Newsletters are archived at http://www.backyardnature.net/n/.
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