September 23, 2012

YELLOW-HEADED BLACKBIRDS
About an hour after sunrise as I was scalping sod from the backyard lawn to make room for gardening a little flock of maybe a dozen heavyset birds settled in the top of the frontyard Sycamore. All the birds' golden chests faced directly into the low morning sun, and beneath the blue sky that was a pretty thing to see. You can see two of those birds at https://www.backyardnature.net/n/12/120923yh.jpg.

Only one North American bird species possesses a yellow head and a black body, and here it was: The Yellow-headed Blackbird, XANTHOCEPHALUS XANTHOCEPHALUS.

Unlike most birds who land atop the big Sycamore to bask in the morning sunlight these birds did not move about finding the most perfect spot, or preen. Silently and unmoving they looked all around, at the hills and the pastures, and at me. It was clear that they were visitors uncertain about where they were. They stayed about five minutes, then one of them gave a low chip and instantly they all rose and flew in a tight formation to some new spot where maybe they'd feel more at ease. When they flew, surprising white patches flashed in their black wings.

I'm sure that these birds were newcomers because Yellow-headed Blackbirds don't nest in this part of the world. Here in southwestern Texas we're right on the boundary of where they're seen only during their spring and fall migrations, and where they overwinter. They spend their winters mostly in northern and central Mexico, but also southwestern Arizona, southern New Mexico and extreme western Texas. They nest throughout most of the western US and southwestern Canada.

Will we have Yellow-headed Blackbirds here this winter? I hope so, for seeing them atop the old Sycamore, their golden chests and the blue sky behind them, is something delicious.

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DAZED GECKO
I was painting one of the cabin's rooms and noticed that a baseboard had come loose from the wall, so I began pounding a nail into it. This resulted in a three-inch-long (8cm) gecko shooting onto the floor, who just sat there looking dazed, and I guess he had a right to be. You can see him, looking pretty good despite what must have been the mother of all headaches, if geckos have headaches, at https://www.backyardnature.net/n/12/120923gk.jpg.

With the big eyes and semi-translucent, reddish body he might be mistaken for a salamander or newt, though I've never heard of one of those living behind a baseboard in a cabin. One indication that the little fellow isn't one of those is that he is covered with scales -- in the picture not very apparent except on the front legs. Salamanders and newts are amphibians, so they don't have scales. Geckos are reptiles, and reptiles do have scales.

This is the Mediterranean House Gecko, sometimes also called Turkish Gecko or Common House Gecko, despite the latter name being applied to another species as well. It's HEMIDACTYLUS TURCICUS, which my Audubon field guide describes as the most conspicuous gecko in North America, despite its being native to the Mediterranean region, Middle East and India. Now the species is spread spottily throughout the world's tropical and subtropical zones.

In the US Mediterranean Geckos were first reported in Key West, Florida in 1915, but now they're found here and there throughout the southern states, coast to coast. Mostly they occur around major urban areas, so ours way off the beaten path in southwestern Texas is a little unusual. So far it seems that the species can't compete with our native lizards in more natural habitats, and is pretty much dependent, like house mice, on the presence of human buildings and general human messes to survive.

Mediterranean House Geckos are entirely nocturnal, reaching their peak of activity around 2 AM. Sometimes you see them beneath lights left on all night, where insects trying to navigate by the stars crash and become gecko food.

We do have a native gecko species here, the Texas Banded Gecko, usually noticed crossing highways at night, and I'll be looking for that one, though instead of behind baseboards that species prefers deserty rock outcrops and canyon beds.

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TUMBLEBUGS
Last weekend my neighbor plowed his pasture next to the cabin where I live, and that resulted in large numbers of tumblebugs rolling balls of manure across our little gravel road. You can see a ball roller at https://www.backyardnature.net/n/12/120923tb.jpg.

Tumblebugs are also called dung beetles, and there are many species of them spread through several genera in the subfamily Scarabaeinae, which alone comprises more than 5000 species. Tumblebugs are a subgroup of scarab beetle. In the above picture the mottling on the beetle's body is dried poop.

Not all dung beetles roll balls of manure. Some species live in tunnels dug beneath piles of poop, and are called tunnelers. Others simply live in the poop, and are called dwellers. Our ball rollers are rollers.

"Rollers" roll and bury a dung ball either for food or for laying eggs in them. During the rolling process other rollers may try to steal the ball, so that explains why all the rollers seen last weekend seemed to be in a hurry. In some species the male and female roll the ball together, while in others the male does most of the rolling, with the female sometimes hitching a ride. The balls I saw being rolled were mostly moved by one beetle. When a spot with soft soil is found the ball is buried. Then the male and female mate underground, and the female lays eggs inside the ball. In some species the beetles remain in the tunnel guarding their offspring

At least in this part of the world tumblebugs are not just unusual oddities; they do important work and people in the know regard them as desirable, beneficial insects. In parts of Texas studies show that dung beetles remove 80 percent of a grazing area's cattle droppings, and that goes a long way in keeping down the numbers of disease-transmitting flies.

Why did my neighbor's plowing cause such a frenzy of ball rolling? Maybe the turned-up soil was easier for the rollers to roll their balls through than the previous forests of grass stems, or maybe the balls had been buried, and now the beetles were transferring their prizes to less disturbed fields. Whatever the case, it was hilarious seeing so many little balls of poop being tumbled across the gravel road.

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CEDAR ELMS FLOWERING
Occasionally in our ocean of Ashe Junipers and Texas Live Oaks you encounter a different tree species. One of those is obviously an elm, its leaves having serrated margins, asymmetrical leaf bases and pinnate, feather-like venation, just the way an elm leaf is supposed to be. However, the leaves are only about 1½ inches long, which is smaller than most other kinds of elm, plus there's something even more atypical of elms, which is that nowadays, here at the beginning of fall, they're flowering. Most elm species flower during the winter to early summer, though in some parts of the US Southeast there's the late-summer-blooming September Elm. You can see our small-leafed, flowering elm at https://www.backyardnature.net/n/12/120923us.jpg.

There's not much to the flowers. Two to five emerge in a cluster from each flower bud. Their calyxes bear five or six hairy lobes, and each flower has the same number of stamens with reddish purple anthers; female stigmas are white and project from the flowers like slender little fingers. You can see this at https://www.backyardnature.net/n/12/120923ut.jpg.

The tree's bark is elmy enough, gray with flat scales, as seen at https://www.backyardnature.net/n/12/120923uu.jpg.

I read that the twigs are often winged with corky ridges, like the East's Winged Elms, but I'm not seeing that on our trees.

We're talking about the Cedar Elm, ULMUS CRASSIFOLIA. Ours was found on the steep limestone slope along our little Dry Frio River, which agrees with the Flora of North America's habitat description of "Stream banks, low woods, low hillsides, roadsides, waste places." The species occurs in northern Mexico and in the US south-central states from extreme western Tennessee south to Louisiana and here in southwestern Texas.

Our trees are only about 20 feet high (6m) but in rainier places they can reach 80 feet (24m).

I find two explanations of why this species is called the Cedar Elm. The first is because of its leaves' rough leaf surfaces, which supposedly is like rough cedar leaves. The second, more convincing reason is that here in the western part of its distribution it's often found with Ashe Junipers, which local people call cedars, and that's completely true.

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CHINESE TALLOW TREES FRUITING
At the water's edge along the Dry Frio River just below the cabin there's a robust tree with dark green leaves looking a little like a cottonwood's, except that the blade margins are smooth instead of serrated. The blades are smallish, only about three inches long (8cm). You can see some on their long petioles, along with some immature fruits, at https://www.backyardnature.net/n/12/120923ch.jpg.

Nowadays some of the capsular, three-lobed fruits are just beginning to split open, each capsule releasing three spherical, white seeds. The seeds are white because they are coated with a white, waxy substance. You can see a split-open fruit with one white seed remaining attached with its funiculus at https://www.backyardnature.net/n/12/120923ci.jpg.

The tree's gray bark is shown at https://www.backyardnature.net/n/12/120923cj.jpg.

This is the Chinese Tallow Tree, TRIADICA SEBIFERA, in the US regarded as a terrible invasive infamous for pushing aside native species, and I'm sorry to see it so well established here. Along the Dry Frio it appears to be replacing American Sycamores, though elsewhere in Texas it's been observed turning Gulf Coast grasslands into single-species forests of Chinese Tallow Trees. It even changes soil conditions with the high levels of tannins in its leaf litter. Unlike most invasives, it can insinuate itself into quality, undisturbed natural forests, displacing native species.

Chinese Tallow Trees are native to China and were introduced into South Carolina in 1776 as an ornamental tree and for seed oil production. The seed's white waxy aril can be used in soap making but the seed's oil is toxic and has proved to offer only limited industrial uses. The ecological damage the tree causes is profoundly greater than any economic value it may have.

The species belongs to the Euphorbia or Poinsettia Family, the Euphorbiaceae.

Chinese Tallow Trees are sensitive to cold so until now they have escaped only in the US southern tier of states, including California plus Oklahoma.

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RAIN LILY
Tuesday at dawn outside the bathroom window there were some white flowers that hadn't been there the previous day. In fact, I was pretty sure that two or three days earlier not even a sprout had been there, for this was naked soil over the septic tank, and I'd have noticed it. You can see the plant at https://www.backyardnature.net/n/12/120923rl.jpg.

The little herb stood only eight inches tall (20cm) and the single blossom spread only about an inch across (2.5cm). It's unusual to see such a relatively large blossom on such a small body.

This is the Rain Lily, COOPERIA DRUMMONDII. The rain part of its name makes sense because last weekend we enjoyed a three-inch rain here after a long dry spell. Rain Lilies arise from subterranean bulbs that wait to sprout until there's a good drenching. I only had three plants but a neighbor's lawn for two or three days was white with them, literally thousands prettily swaying in the wind. I read that Rain Lily flowers open only at night but mine stayed open around the clock. As you might expect of a night-blooming, white flower, its fragrance is intense. One field guide describes its odor as variable. To me it smells like a strong perfumed talc trying to smell like lilac.

Some books place Rain Lilies in the Amaryllis Family, but it seems that with genetic sequencing some experts have decided that there's no real difference between the Amaryllis and Lily Families, so newer guides often place them in the Lily Family. Though such an abundantly-occuring bulb-producing plant would seem a likely source of food if it were edible, I can find no reference to its being either edible or inedible.

Rain Lilies are native to Mexico and the US south-central states, from New Mexico to Alabama, though I've never seen them in Mississippi.

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THREE-AWN GRASS
We're exactly where the Edwards Plateau with its hills and slopes of Cretaceous limestone meets the much younger gravels, sands, alluvium and other soft or loosely consolidated geologic materials of the Coastal Plain. The Edwards Plateau is a southern extension of the Great Plains with its grassy prairies. Therefore, we have interesting native grasses here, and I'm paying attention to them.

For example, on particularly dry limestone slopes where the Texas Live Oaks and Ashe Junipers grow far enough apart for plenty of sunlight to break through, often leg-high clumps of slender-stemmed grasses show up as shown at https://www.backyardnature.net/n/12/120923t3.jpg.

The Easterner might assume that this is one of the broomsedges, but a close look at the flowering heads dispels that notion. Broomsedges produce achene-type fruits equipped with white fuzz that helps the achenes disseminate in the wind. Our oak-juniper clumpgrass achenes are fuzzless, but from their tops arise three slender, stiff bristles that catch on animal fur for critter dissemination, and serve as crude parachutes for wind dissemination. The bristles are shown at https://www.backyardnature.net/n/12/120923t4.jpg.

This distinctive arrangement of three long, stiff bristles arising atop a slender achene tells us that we have a three-awn grass, a member of the genus Aristida. About 300 Aristida species are recognized worldwide, mostly growing in arid, warm regions like here; about 19 Aristida species are listed for Texas. The species in our picture seems to be the three-awn grass most typical for openings in forests of Texas Live Oak and Ashe Juniper, ARISTIDA PURPUREA, often known as Purple Three-awn Grass. It's found on dry, rocky soils on the Great Plains from Utah, Colorado and Kansas south through our area into northern Mexico.

Back when vast herds of buffalo roamed the American prairies this was one of the medium-size grasses they might have munched on if the herd wandered into dry, rocky spots. However, for grass eating herbivores Purple Three-awn Grass isn't a particularly palatable species, since its nutrient value isn't as good as some other species, plus, when the grass is fruiting, those long bristles stick in a grazer's throat and can cause sores in the stomach.

Still, small birds such as juncos eat the seeds, plus the grass produces a large network of fine roots, so an important service Purple Three-awn Grass provides for our rocky slopes is to hold the soil in place, which greatly benefits the whole ecosystem.

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BUFFALO BUR
I can go barefooted around the cabin, but ever now and then I do get a sticker in my foot. You can see the main culprit at https://www.backyardnature.net/n/12/120923so.jpg.

The plant in the picture is only about a foot tall, but one that's taken over an abandoned flowerbed where the soil is rich and deep stands a yard tall (1m). Even the spines on plants that were chopped down months ago and now are brown and humusy remain sharp and stiff enough to stick you, so just avoiding the easy-to-recognize plant isn't enough to keep away from foot-stabbing spines.

Besides the spines, which remind us of the barnyard weed called Horse Nettle, in the picture notice that the deeply lobed leaves -- a good one is in the picture's upper-left corner -- look like potato leaves, and the flowers are similar to tomato flowers. Well, Horse Nettle, the Potato and the Tomato all are members of the Nightshade Genus Solanum, of the Nightshade Family, the Solanaceae, so it shouldn't surprise us that our foot-stabbing plant also is a Solanum. It's SOLANUM ROSTRATUM, often called Buffalo Bur. Buffalo Bur is native to the US Southwest, but it's tough and aggressive enough to have become invasive throughout the US and much of Canada.

It's always interesting to look at a Solanum flower, so a close-up of a Buffalo Bur blossom is at https://www.backyardnature.net/n/12/120923sp.jpg.

The anthers -- the part of the stamen in which pollen is formed -- are the most distinctive part of the flower. In our Solanum blossom they look like a clump of slender bananas in the blossom's center. It's normal for Solanum that there are five anthers, but notice that four of the anthers are alike, while the fifth is much enlarged. Also notice that, unlike the vast majority of anthers in other flowers, these anthers do not split open to release their pollen along their sides, but rather each anther tip bears two tiny pores through which the pollen exists. This is something special about the genus Solanum.

Below the clump of anthers you can also see the slender, upward-curving style, which is the ovary's neck. Pollen from other flowers lands on the stigma at the style's tip, germinates, and sends a rootlike, male-sex-germ-carrying pollen tube down through the style to the ovary, where fertilization takes place.

The very spiny fruits -- which botanically are berries because they contain several seeds, don't split open upon maturity, and are more pulpy than dry -- are about 3/8ths inch across (1cm). There's a close-up at https://www.backyardnature.net/n/12/120923sq.jpg.

Buffalo Bur, like many of its fellow nightshades, is toxic. However, few herbivores would want to eat such a prickly plant, so you don't hear much about Buffalo Bur poisoning.

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TEXAS BINDWEED
In the Yucatan we had so many beautiful and remarkable members of the Morning-Glory Family that I got especially sensitized to the group. Therefore I was delighted when a morning-glory species I'd not seen before turned up tightly twining around the wire fence around my neighbor's pasture. You can see it at https://www.backyardnature.net/n/12/120923co.jpg.

The blossom is small for a morning-glory, only a little over an inch across (3cm), and just look at how slender the arrow-shaped leaves are on the right, and notice how the leaf bases bear long "ears." A closer look at a leaf base is shown at https://www.backyardnature.net/n/12/120923cr.jpg.

Such arrow-shaped leaves with narrow, backward-pointing ears, or "basal lobes," are said to be "hastate." And notice that these hastate leaves are particularly hairy with sharp hairs lying low against the leaf's surface. These are important field marks for this species. Another field mark is shown in the flower close-up at https://www.backyardnature.net/n/12/120923cp.jpg.

The thing to notice there is that the female style is divided into two long, slender stigmas. Morning-glories that are members of the big genus Ipomoea have a spherical stigma very unlike this. Another field mark is the flower's unusual calyx with broadly overlapping sepals, shown at https://www.backyardnature.net/n/12/120923cq.jpg.

So, all these eye-catching field marks mean that here we have the Texas Bindweed, CONVOLVULUS EQUITANS, found in much of the arid US Southwest and northern Mexico. It's closely related to a much more widely spread and weedier Bindweed, Convolvulus arvensis, which we met in Oregon, but our Texas plant's leaves are much narrower. You can compare our Texas one with the more common weedy species at https://www.backyardnature.net/n/h/bindweed.htm.

Birds eat Texas Bindweed's seeds, pollinators visit its flowers and bugs eat its leaves, but the plant is really too small and inconspicuous to make much of an impact on the usual human mind. To get a kick from it you have to be looking for special things in obscure little corners.

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FEATURED ESSAYS FROM THE PAST:

"Snake Brain," from the July 20, 2006 Newsletter, at https://www.backyardnature.net/n/p/060720.htm.

"The Story Teller" from the August 11, 2008 Newsletter, at https://www.backyardnature.net/n/p/080811.htm.

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Best wishes to all Newsletter readers,

Jim