JIM CONRAD'S
NATURALIST NEWSLETTER
Issued from the valley of the Dry Frio River on the
southern slope of the Edwards Plateau, northern
Uvalde County, southwestern Texas, USA

May 25, 2014

AOUDAD SHEEP
Biking down the one-lane gravel road in the upper Dry Frio Valley at first I figured that the seven or eight deer-size, sandy-brown critters on the road up ahead were just the usual white-tails or Axis Deer. However, when they began scrambling up the slope beside them they didn't move like deer. Remembering that here several big landowners who sell hunting rights to their ranches stock exotic species -- you might recall the Nubian Ibex spotted in my neighbor's goat pen last year -- I skid to a halt, retrieved the camera and snapped the picture shown at http://www.backyardnature.net/n/14/140525ao.jpg.

Seeing the horns, my first impression was that they were Bighorn Sheep too young to produce that species' massive horns. Our picture even compared well enough with images of juvenile Bighorn Sheep on the Internet. However, I couldn't find reference to Bighorns being stocked in Texas, except in the Big Bend area well west of here. At that point I began browsing pictures of animals advertised on websites of local "game ranches."

They're Aoudad Sheep, also called Barbary Sheep and other names, AMMOTRAGUS LERVIA, native to rocky mountains in northern Africa, where the species is rare. However, Aoudads have been introduced to North America, southern Europe, and elsewhere, mostly by game ranches who invite hunters to shoot them.

If these Aoudads had been facing us instead of running away, it would have been easy to distinguish them from young Bighorn Sheep because Aoudads have shaggy hair on the throat that, on males, extends down to the chest, while Bighorns don't. Returning to other pictures I'd taken that morning, one shot showed a male turning around to look at me, just barely showing a shag dangling from his chest. Look at the one in the lower, right corner at http://www.backyardnature.net/n/14/140525ap.jpg.

Aoudad Sheep tails are also are much longer than those of Bighorn Sheep.

One hunting lodge offers a package "Trophy Aoudad Sheep Hunt" for $3750, and that price is in addition to $250 per day for the "All-Inclusive Hunt Package." The same lodge offers similar hunting packages for Addax, Axis Deer, Blackbuck Antelope, Buffalo, Fallow Deer -- and that only gets us to F on their list. One wonders what the long-term effect will be on the ecology when such introduced species escape into the landscape here.

Aoudad Sheep belong to the Bovid Family of mammals, the Bovidae. Bovids are cloven-hoofed (hoof split into two toes), are ruminants (usually cud-chewing), and bear non-branching horns. Within the Bovid Family, Aoudads belong to the Subfamily Caprinae, often known as goat-antelopes. This brings up the question of "What's the difference between goats, sheep and antelopes?

The easiest way to tell the difference between a sheep and goat is to look at their tails. A goat's tail goes up, unless it's sick or upset, while sheep tails hang down. Antelopes are harder to define, the term being used for species that are neither cattle, sheep, water buffalo, bison, nor goats. By the way, antelopes don't shed their horns, but deer do.

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FLEDGLING-FEEDING TIME
Nowadays at the bird feeder new species are showing up, such as Painted Buntings, Blue Grosbeaks and White-winged Doves. Also now here and there in the liveoak branches just beyond the feeder throughout the day you see shy-acting birds perched with their heads pulled into their shoulders and occasionally quivering their wings. These are fledglings eager to encourage their parents to come plop food into their mouths. The harried parents grab seeds from the feeder, grind them a bit between their mandibles, and when particles are small enough go feed their kids. You can see a Chipping Sparrow about to deliver such a meal at http://www.backyardnature.net/n/14/140525hg.jpg.

The parents are so busy and probably so tired and with such frazzled nerves that you see them behaving more clumsily than normal, as in the picture, where the parent has landed awkwardly, tangling wing feathers with liveoak leaves.

Another picture of the same thing, this time a House Finch family lit by dawn's first light, is at http://www.backyardnature.net/n/14/140525hf.jpg.

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ANNUAL CICADA EMERGING
Something caught my eye in tall grass in a wild stretch of the upper Dry Frio Valley. It turned out to be a black, shriveled and half decomposed mushroom, but beside that -- well camouflaged and unseen until my hand grazed it -- was what's shown at http://www.backyardnature.net/n/14/140525cc.jpg.

Another picture, closer up, is at http://www.backyardnature.net/n/14/140525cd.jpg.

That's a very young cicada freshly emerged from its brown exoskeleton, which dangles from the straw below the cicada. You can see that the cicada is so recently emerged that its wings are still so pliable that they bend easily without fracturing. I've never seen any cicada species with this one's green and yellow hues, but freshly emerged individuals often are colored different from how they will appear as adults. Not knowing the species, it's just unclear whether this will be a greenish yellow adult or not.

Volunteer identifier Bea in Ontario submitted the pictures to BugGuide.Net, and before the day was out Bill Reynolds in Raleigh, NC commented that "... it might be a teneral Tibicen sp. (perhaps one of the smaller western species)."

The nice word "teneral" is an adjective describing the stage when an adult insect is newly emerged from the pupal case or nymphal skin and not yet functioning as an adult. "Tibicen" is a cicada genus embracing species known as annual cicadas. Since Bill is the Curator of the Arthropod Zoo at the North Carolina Museum of Natural Sciences, I figure that his designation as a "teneral Tibicen" is about as far as we're going get with this identification.

That last picture, with the cicada upside-down beneath his straw, shows some interesting features not usually seen in normal cicada views. For example, to the left of the brownish abdomen segments in the picture's top, right corner, there are two large, thumbnail-shaped scales, or plates. The darker, bottom one is the "tymbal cover," which covers the membrane-like tymbal, which is connected to a tymbal muscle. The muscle can contract and release very fast causing the tymbal to vibrate about 4,000 times per second. This vibration creates a sound, the loudness of which is increased inside the cicada's somewhat hollow abdomen, which serves as a resonator. This loud rattling sound is then radiated by the tympana.

In our picture, the tympana are covered by the large, greenish plate above and to the left of the tymbal cover (It'd be "below" if the cicada weren't upside-down). That plate is the operculum, which protects the delicate tympana beneath it. Females, not having to call, don't have large tymbals and typana, so they display much smaller operculums than ours has. Before long, our male should be drumming loudly from a neighborhood tree.

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SOPHORA WORM
On our limestone hills one of the most common bushes or small trees is a Bean Family member with locust-like leaves and producing very eye-catching flowers and pods. Local people call it Mountain Laurel but outside the area it's better known as Mescalbean. Our Mescalbean page is at http://www.backyardnature.net/n/w/sophora.htm.

The other day a Mescalbean bush turned up with the newly deployed leaves at the tip of its branches nibbled away by some kind of critter, as shown at http://www.backyardnature.net/n/14/140525cq.jpg.

In that picture some scraps of silk webbing can be seen, looking like a halfhearted effort made by tent caterpillars. Looking for caterpillars beneath leaves in the vicinity, sure enough some smallish, fuzzy caterpillars turned up looking a little like tent caterpillars, as shown shown at http://www.backyardnature.net/n/14/140525cp.jpg.

Last week we looked at how volunteer identifier Bea in Ontario uses Bugguide.Net to figure out insect names. This week when I told Bea that the unknown caterpillar was eating Mescalbean, Sophora secundiflora, she tried a different technique: She did an image search on Google using the keywords "caterpillar Sophora secundiflora" ... and instantly got a direct hit.

Our Mescalbean-eating caterpillar is URESIPHITA REVERSALIS. In North America the caterpillar often is called the Sophora Worm, though it's unfortunate that a fuzzy caterpillar is called a worm. At least the Sophora part is exactly right. In books the small, brown, triangular, plain-looking moth the caterpillar produces usually is called the Genista Broom Moth, which also is unfortunate, since Genista Broom is an Old World plant, but Uresiphita reersalis is a native American insect occurring coast to coast from southern Canada through the US into northern Mexico.

Sophora Worm feeds mainly on Bean Family members such as acacias, lupines, and Genista Broom (invasive in parts of North America), plus it's been noticed on Crapemyrtle and Honeysuckle.

Despite Sophora Worms looking and behaving somewhat like tent caterpillars, they're in entirely different families, so they're not too closely related.

*****

STAR-THISTLE
Lined up right beside the little gravel road running down the upper Dry Frio River Valley was a 15-inch high (40cm) row of fairly scrappy-looking, nondescript, even disreputable-seeming weeds, as shown at http://www.backyardnature.net/n/14/140525ct.jpg.

I'd have ignored them, but some bore brightly yellow specks at their tops, so maybe they were flowering. Up close the yellow specks were indeed clusters of tiny, yellow disc flowers emerging from a spectacularly spiny, almost spherical involucre, shown at http://www.backyardnature.net/n/14/140525cu.jpg.

The involucres were only about as wide as a thumbnail, but up close there's something pretty about them, as you can confirm in a portrait of a single head at http://www.backyardnature.net/n/14/140525cv.jpg.

With many tiny flowers with yellow corollas arising from the involucre, we know that our plant is a member of the huge Composite or Daisy Family. You can see one disc flower teased from the above head, looking a little like such a flower removed from a Dandelion head (Dandelions are composites), at http://www.backyardnature.net/n/14/140525cw.jpg.

In that picture, the yellow, cylindrical corolla is obvious. The oval, white thing is the future cypsela-type fruit (dry and not splitting at maturity), and the white hairs are the "pappus," which will develop into a "parachute" atop the future fruit, helping the fruit disperse in the wind.

Most of us would guess that with such spines these plants must be a kind of thistle, and they are, though the term "thistle" often is applied to just about any spiny, herbaceous plany. However, a more precise concept of "thistle" is that they are members of the Composite-Family "tribe," the Cynareae. The main thistles in this tribe belong to the genera Cirsium and Carduus, but our roadside plants are not one of those, so here we have a somewhat non-standard thistle. You can believe that better when you realize that these thistles' leaves don't bear spines the way a good thistle should, as demonstrated at http://www.backyardnature.net/n/14/140525cx.jpg.

With such great field marks, especially the non-spiny leaves accompanying very spiny flowering heads, it's easy to identify our roadside plants as star-thistles, members of the genus Centaurea. Several star-thistle species can occur in our area, but our yellow-flowered ones can only be one of two species, both species known as Yellow Star-thistles.

One of those Yellow Star-thistles is Centaurea solstitialis, which during our summer in Oregon in 2009 we got to know very well because they were so abundant and painful to sit on or walk on barefooted. Our page showing that species is at http://www.backyardnature.net/n/h/starthst.htm.

You can see that that the spines of that species' involucres are much longer and slenderer than our current ones. Therefore this is the other yellow-flowered species, sometimes also known as the Tocalote or Maltese Star-thistle, CENTAUREA MELITENSIS.

Both of these Yellow Star-thistle species are native to the Mediterranean region, and both invade disturbed soil in our area. Though our current species could be awful to step on barefooted -- or to bite into if you're a cow -- it's not nearly as aggravating as the one we saw in Oregon, whose spines somehow cause more trouble.

*****

ITALIAN THISTLE
Right next to the Maltese Star-thistle stood another Mediterranean thistle, shown at http://www.backyardnature.net/n/14/140525th.jpg.

That's a more normal thistle, one with large, stiff spines not only on the flower head's urn-shaped involucre but also the leaves. A shot of a spiny-margined leaf is at http://www.backyardnature.net/n/14/140525tj.jpg.

At first I thought this plant was our similarly small, commonly occurring Texas Thistle, which you can compare at http://www.backyardnature.net/n/h/texthist.htm.

Notice that the Texas Thistle produces just one flowering head at the tip of each of its branches, while the current one clusters three or so. Also, the Texas Thistle's involucral bracts are very distinctive, bearing short, slender spines and silvery markings on their flat surfaces, while this thistle bears completely different kinds of involucral bracts, as seen at http://www.backyardnature.net/n/14/140525ti.jpg.

Realizing that a new thistle species had turned up, a head was broken open, revealing a white, egg-shaped, future cypsela-type fruit atop which a ring of slender, white hairs arose, almost obscuring the cylindrical, disc-type corolla, shown at http://www.backyardnature.net/n/14/140525tk.jpg.

In that picture it's worth nothing that the hairs, or "pappus bristles," are simple, not featherlike as they are in some thistle types. Also, the hairs arise from atop the broad head of the future fruit itself, not from a slender neck atop the fruit, which sometimes you see among other thistle kinds.

So, our new thistle often is known as the Italian Thistle. It's CARDUUS PYCNOCEPHALUS, introduced in ship ballast into several east-coast ports in the 1800s, but apparently not doing well there. However, now Italian Thistle has become a serious rangeland invasive in much of California, especially near the coast where it sometimes forms pure stands, both in full sun and in partial shade. Populations increase under grazing pressure as more palatable plants are eaten by livestock. A healthy population also seems to be establishing itself in central Texas.

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CANADA WILD RYE
A deer fence around the abandoned garden at the red cabin I lived in two winters ago is grown up at its base with various interesting "weeds." One of those is a distinctive grass with spikelets arranged in stem-top heads reminiscent of bristly bottle brushes. You can see what I mean at http://www.backyardnature.net/n/14/140525el.jpg.

Up close, individual spikelets display a very specialized and unique structure that quickly identifies the grass as a kind of wild rye, genus Elymus, shown at http://www.backyardnature.net/n/14/140525em.jpg.

In that picture, one feature making this a wild rye is that at the picture's bottom a pair of spikelets -- not a single spikelet or a cluster of them -- is attached to the flowering stem, or rachis. A little higher up the rachis but on the opposite side, another pair of spikelets arise, and so on, on up the inflorescence, causing the rachis to be configured like a zigzagging stepladder.

An even more distinctive field mark designating the wild ryes is to be seen in the grass's glumes. To better make out the needle-like glumes, a shot of two spikelets removed into the palm of my hand is at http://www.backyardnature.net/n/14/140525en.jpg.

Normal grass spikelets have at their bases two modified bracts, the glumes, situated opposite one another, like the wide-open mandibles of a bird with his mouth pointed skyward. One or more florets arise above the two glumes. The spectacular thing about wild rye spikelets is that not only are their glumes not opposite one another, being side by side, but also instead of being like a bird's upward-pointing, open mouth, they're stiff and needle-like, forming thin-sided Vs, with florets arising above the V's base.

In our area two wild rye species commonly occur. The main field mark distinguishing the two species is that one, Virginia Wild Rye, produces much thicker, flatter glumes than the other, which is Canada Wild Rye. Back in Mississippi we looked at the Virginia Wild Rye. You might check the picture of that species' glumes partway down the page at http://www.backyardnature.net/n/h/wild_rye.htm.

You can see that our present wild rye's glumes are much slenderer, because now we have Canada Wild Rye, ELYMUS CANADENSIS. Canada Wild Rye is a native species found throughout much of Canada and most of the US, though generally uncommon or absent in the US southeastern and Pacific states, but extending southweard into northern Mexico.

Canada Wild Rye has to be fairly tough and adaptable to thrive over such a large area, and finding our plant surviving where most of its companion weeds were severely stunted or didn't even emerge this year because of the drought, shows that it's drought tolerant as well. It's also noted for doing well in partly shaded areas.

This is a fine grass. Despite the needlelike "awns" produced on its flowering heads, the awns are soft and livestock like grazing on Canada Wild Rye.

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WESTERN PANICGRASS IN SPRING
Last November we looked at our commonly occurring Western Panicgrass, Dichanthelium acuminatum. At that time I mentioned that the species overwinters as small rosettes of short, thick leaves, and that it flowers both in spring and fall. In November our plants' flowers appeared among dense tufts of leaves held well above the rosette forming for the winter, as documented at http://www.backyardnature.net/n/h/panic-1.htm.

Now our Western Panicgrasses are flowering again, but in spring they look very different than they did last fall. The airborne leaf tufts so conspicuous back then now have withered, died and collapsed, but in their place panicles of flowers are held aloft, as seen at http://www.backyardnature.net/n/14/140525pa.jpg.

In that picture, notice last fall's dead, bleached leafy tufts sprawled on the ground in the picture's lower, right corner. A close-up of the classic panicle-type inflorescence is at http://www.backyardnature.net/n/14/140525pb.jpg.

Western Panicgrass is famous for being very variable, especially in terms of hairiness, so for serious identifiers who eventually will read these words, a look at its ligule area at the base of a leaf is shown making clear this particular plant's philosophy of hairiness at http://www.backyardnature.net/n/14/140525pd.jpg.

Western Panicgrass is one of the most widespread, commonly occurring panicgrasses in North America, appearing coast to coast, from Candada south through the US, Mexico and Central America, into northern South America, varying prodigiously as it goes.

*****

JUNIPERS IN A DROUGHTY FIELD
At http://www.backyardnature.net/n/14/140525ju.jpg you can see a field in the Dry Frio Valley where the two most striking features are that Ashe Junipers are making a gradual come-back after being cleared from the field a few years ago; and the field itself is parched and crisp with dryness, indicating just how severe our drought is. This time last year the field was green, and I'm told that at this time in years before that it was not only green but also resplendent with untold numbers of flowering wildflowers.

Ashe Junipers don't sprout from their bases when their tops are removed, so these young trees "parachuted" into their locations as seeds in bird droppings.

I'm delighted with the Ashe Juniper's ability to rebound despite the constant struggle of many landowners to exterminate it. Viewing the picture, it's easy to believe that in a few years, if left alone, this field will be a juniper forest. The Ashe Juniper controversy, the false notions behind people's efforts to exterminate them, and documentation relating to it all is available on our Ashe Juniper page at http://www.backyardnature.net/n/w/ashe-jun.htm.

One reason people give for killing them is that they don't want junipers to take over everyplace. It's true that in certain locations junipers can create almost pure stands, but from the sky you can see the real situation, as shown in the Google Earth photo at http://www.backyardnature.net/n/14/140525jv.jpg.

In that picture of the southern edge of the Edwards Plateau, the dark areas are wooded slopes dominated by Ashe Junipers. The much more abundant pale zones are pastures, fields, agricultural land or scrubland, either on gently rolling land atop the plateau at the top of the picture (north), or level land of the lower Coastal Plain at the bottom of the picture, or deforested river valleys cutting across the center of the picture. The pale dendritic patterns within the dark band of junipers across the image's center are deforested valley floors draining onto the Coastal Plain to the south. Our Dry Frio River Valley is one of the smaller valleys, wedged between the much larger Nueces and Frio River Valleys, appearing on the image as the two largest dendritic patterns on the image's left side. The point is that on a regional basis forested land is relatively restricted.

As we've documented in this Newsletter, our Ashe Juniper-dominated hills harbor a remarkable assemblage of narrowly endemic species exquisitely adapted to just our area, and to just our precise conditions. When I see a field being invaded by Ashe Junipers where earlier all junipers had been cut, piled into heaps and burned, I am deeply gratified.

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FEATURED ESSAYS FROM THE PAST:

"Clothes Dryer" from the June 22, 2003 Newsletter, at http://www.backyardnature.net/n/p/030629.htm

"Putting a Price on Nature" from the November 1, 2005 Newsletter, at http://www.backyardnature.net/n/p/051101.htm

*****

Best wishes to all Newsletter readers,

Jim

All previous Newsletters are archived at http://www.backyardnature.net/n/.