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

March 31, 2013

CLAY-COLORED SPARROW
All winter so many Chipping Sparrows have wandered about the neighborhood in small to fairly large flocks that when I was washing dishes and a stripe-backed, plain-chested sparrow appeared foraging on the ground below the kitchen window I assumed it was one of them. However, this bird had a very conspicuous and well defined gray stripe through his crown, which Chipping Sparrows don't. You can see him perched on a Prickly Sow Thistle, with an inset showing him hopping on the ground, at http://www.backyardnature.net/n/13/130331c2.jpg.

Besides the head stripe, this bird displayed a dark cheek patch completely surrounded by a whitish face. Immature Chipping Sparrows also have brown cheek patches, but not as well defined as this.

In short, this was a Clay-colored Sparrow, SPIZELLA PALLIDA, belonging to the same genus as the Chipping Sparrow and closely related to it. Birders in both eastern North America and most of the West normally don't see Clay-colored Sparrows in their regions because this is one of few bird species distributed nearly entirely in mid continent. It overwinters in Mexico and southern Texas, migrates through the central US grasslands, and nests in the north-central US states and south-central Canada.

There's a very striking and informative animated map displaying the Clay-colored Sparrow's migration route throughout the year, with the spring route shown taking a more easterly course than the fall one at http://ebird.org/content/ebird/about/occurrence-maps/clay-colored-sparrow.

That map indicates that at this time of year our part of southwestern Texas is "white hot" with concentrations of Clay-colored Sparrows crossing the border from Mexico and headed north. Then as the animation proceeds through summer, notice how the nesting population in the north-central states shifts to the west before beginning the fall trip back to Mexico. The map shows that during fall migration, much in contrast to now, our part of Texas sees few Clay-colored Sparrows, for the largest numbers return to Mexico via New Mexico and extreme western Texas, including the Big Bend area. Maps like this, based on observations by untold numbers of birders in the field, are revealing patterns of migration not hitherto realized.

Apart from this seasonal shift of migration route, Clay-colored Sparrows are known to be expanding their range eastward.

The species is known to flock with their Chipping Sparrow cousins, as well as with similar looking and closely related Brewer's Sparrows. All three species might be found here, and I suspect that I've been overlooking the Brewer's, distracted by all the Chipping Sparrows.

The Clay-colored Sparrow's primary habitat is described as isolated stands of shrubs and trees within a grassland matrix, though they also are known to turn up in open, dry coniferous forests, overgrown pastures, shelterbelts and even in suburban zones.

*****

COWBIRD FLOCK
Hearing a familiar quick, upward rising, bubbly, fluty bird call, I looked up and saw a nearby treetop blackened with dozens of stocky, black birds. The call must have been a signal to move on because the moment I focused on them the whole flock launched from the tree, made a big circle over the neighbor's pasture, and landed next to Minnie the Cow and the unnamed pony. You can see this at http://www.backyardnature.net/n/13/130331cb.jpg.

From the up-swinging, bubbly, fluty call and behavior I knew that at least some of the birds, if not all, were Brown-head Cowbirds. During the winter this species often flocks with other blackbird species and starlings, but in the picture I can only find thick-necked, short-tailed, heavy-set Brown-headed Cowbirds, so maybe this is a pure cowbird flock migrating northward. I've not seen such a flock all winter. Some Brown-headed Cowbird flocks are much larger than this one. The Cornell Lab of Ornithology's page on the species mentions a cowbird flock in Kentucky of over five million birds.

On our own Brown-headed Cowbird webpage we've described how birds in the species are "nest parasites" -- females lay their eggs in the nests of other bird species, at the detriment or even with the complete destruction of the "host" mother's own nestlings. You can read about that down the page at http://www.backyardnature.net/n/b/cowbird.htm.

When you see these big flocks of Brown-headed Cowbirds, it's a bit chilling to think that every bird in the flock is the result of such nest parasitism, and so many personal tragedies for the pairs of parasitized nesting songbirds. Before Europeans settlers populated middle America, Brown-headed Cowbirds followed Bison on the prairies. When forests were cleared in the East new grasslands were created, enabling cowbirds to extend their range eastward. In Nature Brown-headed Cowbirds typically parasitize nests at the woods edge, but in a landscape of many small forest patches the "forest edge habitat" often becomes more common than deep forest, enabling cowbirds to exert an unnatural and very destructive influence on songbird populations, thanks to human help.

A detailed look at cowbird influence on songbirds is presented at http://faculty.ncwc.edu/mbrooks/pif/Fact%20Sheets/Cowbirds.htm.

*****

SANDPAPER OAK FLOWERING
On the very thin, dry soil and between cracks in rocks atop the limestone hills lining the Dry Frio River Valley you find plants that don't grow in the valley and on the hills' slopes. Each hilltop constitutes a special ecological island.

One unique tree species growing on these hilltop islands and not elsewhere in the Valley is an oak tree very unlike what most people visualize when they think of oaks. Our hilltop oak hardly grows higher than one's head and it is much branched from the base like a bushy shrub. Its semi-evergreen leaves are tiny compared to most oak leaves, and when the leaves mature they're rough to the touch. Nowadays the little oak is issuing leaves and flowers, as shown with my finger in the picture for scale, at http://www.backyardnature.net/n/13/130331qu.jpg.

The longish clusters of yellow items are expanding catkins of immature male flowers. A close-up of the tiny leaves is at http://www.backyardnature.net/n/13/130331qv.jpg.

Those leaves are nearly as large as they get, the maximum mature length usually being about 1-½ inches (40mm).

Because of the mature leaves' rough upper surfaces this species is often referred to as the Sandpaper Oak, but also it's called Scrub Oak, Scrub Live Oak, Shin Oak, and Pungent Oak. It's QUERCUS PUNGENS, found on dry limestone or igneous slopes, usually in oak, pinyon, and juniper woodlands in the Edwards Plateau region of southwestern Texas, and spottily in chaparral and the Chihuahua Desert in southern Arizona, New Mexico, and all across arid northeastern Mexico.

Sandpaper Oak's leaves are semi-evergreen in the sense that the shrubs on our hilltops have mostly lost their leaves from last year, except along their lower branches. Some branches are sprouting new leaves at their tips even as last year's leaves remain farther back along the stem.

Later in the season it'll be a pleasure seeing the tiny acorns, which reach only about 3/8ths of an inch long (10mm).

*****

TEXAS RED OAKS FLOWERING
Back in September we looked at our endemic Texas Red Oaks, the story still online at http://www.backyardnature.net/n/w/texasred.htm.

Early in the winter the trees' leaves turned to a dark red, then brown, and slowly over the winter most of the leaves fell off. Nowadays their branches are sprouting new stems, leaves and flowers, as shown at http://www.backyardnature.net/n/13/130331ok.jpg.

The dangling, pagodalike items are catkins of male flowers.

*****

WHITE MULBERRY TREES FROST-NIPPED
One afternoon this week the temperature rose to 95°F (35°C), but then a couple of mornings later the grass was white with frost. At dusk before the morning of the frost I was so struck by the prettiness of the White Mulberry tree in front of the house with its fast-expanding leaves and flowers luminously backlit by the setting sun that I took the picture shown at http://www.backyardnature.net/n/13/130331mq.jpg.

Two days later it was clear that that night's frost had hurt each of the six White Mulberries around the cabin. Look at the leaves and spikes of female flowers topped with fuzzy, white stigmas at http://www.backyardnature.net/n/13/130331mp.jpg.

There you see leaves that before the frost were yellow green and spreading wide like fans but now are darkened and curling upon themselves. The female flowers are turning brown, too. Each spike of female flowers was destined to become a sweet, succulent mulberry before the frost, but now it's clear that this year's mulberry crop will be severely diminished, if there is one at all. Mulberry trees bear separate male- or female-flowered spikes. Usually trees are either entirely male or female, but sometimes both kinds of spikes appear on the same tree. You can see white, pollen producing anthers on dangling male-flowered spikes next to leaves and stems equally frost-damaged as those in the last picture at http://www.backyardnature.net/n/13/130331mo.jpg.

Of the several trees planted around the cabin, some were more advanced with their flowering than others. Maybe the later-flowering ones will produce some mulberries later in the season. Also, here and there along stems of even the most damaged trees certain buds now are issuing stunted, late-flowering, but apparently undamaged flowers and leaves, as shown at http://www.backyardnature.net/n/13/130331mr.jpg.

White Mulberries, MORUS ALBA, are introduced from northern China. In other words, they did not evolve to be adapted to our kind of wildly changing climate, nor for a globally warming planet. Our native plants, even those also flowering when the White Mulberries were blooming, don't seem to have been hurt by the frost. They have evolved adaptations that served them well on the morning of the mulberry-killing frost.

*****

CLARET-CUP CACTUS AFLAME
Atop one of many limestone hills framing the little Dry Frio River Valley within bike riding distance of here there's a cactus very unlike the usual flat-faced pricklypears so abundant in our landscape. This hilltop cactus is formed of short, branched, cylindrical stems tightly crammed into hemispherical masses the size of bushel baskets and larger, all snugly wedged between jagged limestone rocks.

This hilltop cactus has just begun flowering. On early mornings when the sunlight glares on limestone and forms cold, satiny shadows between the rocks, the cactus's blood-red flowers ignite in the sunlight like hard-burning flames, and you just stand there looking at them in wonder, sensing something transcendental taking place, feeling honored just to be there. Though my picture of this loses so much on its journey from that hilltop to you, you can get a small sense of the feeling around the cactus at http://www.backyardnature.net/n/13/130331cc.jpg.

Notice how the cactus's spines arise in star-shaped clusters distributed along "ribs" of the cactus's body.

This is ECHINOCEREUS COCCINEUS, known as the Claret-cup or Scarlet Hedgehog Cactus, distributed mainly in the Chihuahua Desert of northern Mexico, but also in southern Arizona, New Mexico and western Texas. The online Flora of North America describes it as occupying a number of habitats -- desert scrub and grasslands, pinyon-juniper and oak woodlands, Great Plains grasslands, montane forest, bajadas, rocky slopes, and cliffs, igneous, metamorphic, and limestone substrates -- and as such the species varies considerably from place to place. For instance, populations form an intergrading series from densely spine-covered ones in Colorado and northern New Mexico to sparsely spined plants in west-central Texas. The Flora says that some specimens may have as many as 22 spines per cluster, while you can see that our plants' clusters average only six or seven, as shown at http://www.backyardnature.net/n/13/130331cd.jpg.

A close-up of a single cluster is at http://www.backyardnature.net/n/13/130331cf.jpg.

If you are familiar with cactus anatomy you know that spines don't randomly arise from the cactus's surface, but rather from distinct roundish, often white and fuzzy locations called areoles. If you touch your finger to the areole from which spines on a pricklypear cactus arise, microscopically small spines called glochids will stick into your fingertip and may be hard to dislodge, even with tweezers. Lots of cactus types have areoles with glochids arising among their spines' bases, but Echinocereus is one genus in which there are no glochids. That's a wonderful feature for those of us with the urge to poke cacti with our fingers.

You can see a Claret-cup blossom catching its share of sunlight at http://www.backyardnature.net/n/13/130331ce.jpg.

While confirming our cactus's identity by keying it out in the genus key of the Flora of North America, there's a point early in the key where the keyer must judge whether the blossom of the specimen being examined displays the "hummingbird pollination syndrome" or the "bee pollination syndrome."

Blossoms subscribing to the hummingbird pollination syndrome display one or more of the following features: flower centers that are mainly red or reddish; the tepals (flower's colored parts) are stiff enough for a hummingbird to perch on; tepals more or less rounded; flowers have pink to yellowish-purple anthers; inner stamens are longer than outer ones; innermost stamens unite at their bases to form nectar chambers, and; flowers remain open at night and in cold temperatures.

Blossoms displaying the bee pollination syndrome often have one or more of the following characteristics: yellow to brownish or pink to purple centers; tepals usually somewhat pointed and/or thin and delicate; anthers yellowish; inner stamens shorter than outer and don't unite at their bases to form a nectar chamber, and; the flowers partly or completely close at night and during cold temperatures.

The Claret-cup keys out as employing the hummingbird pollination syndrome.

*****

JAPANESE RADISH FLOWERING & FRUITING
At http://www.backyardnature.net/n/h/jap-rad.htm we look at the Japanese Radishes that over the winter have grown in my raised beds, and which have contributed a nice taste and texture to very many salads. Not only the plants' roots but also their leaves were good diced into salads. Now that days are growing longer and warmer some of my radishes are bolting, issuing long racemes of white flowers that in some cases already are "going to fruit." You can see some flowers at http://www.backyardnature.net/n/13/130331cj.jpg.

Radishes are members of the Mustard Family, the Cruciferae, and that word Cruciferae is based on the Latin "crucifer" meaning "cross bearing," as is "crucifixion." You can see in the above picture that the Mustard Family's crosses being referred to are the four-petaled flowers. All Mustard-Family blossoms bear four petals, except in those species with no petals. That field mark helps us recognize members of this family. Many plant families produce flowers with three or five petals, or multiples of three or five, than four. You can see another diagnostic field mark of Mustard Family flowers at http://www.backyardnature.net/n/13/130331ci.jpg.

There two petals have been removed so you can see the blossom's six stamens with their yellow, oblong, pollen-producing anthers atop their slender, greenish filaments. Notice that two stamens are shorter than the other four. It's like this throughout the big Mustard Family, so when you see a flower with four petals and six stamens of which two are shorter than the others, a good bet is that you have a member of the Mustard Family. By the way, flowers bearing four long stamens and two shorter ones are said to be "tetradynamous."

Mustard Family members also produce fairly distinctive pod-type fruits. Pod fruits are just those that split apart to release seeds when the fruits dry out. In the Mustard Family when the pod is longer than broad it's called a "silique," but when it's as broad as long it's a "silicle." You can see the Japanese Radish's silique-type fruit with its outlandishly long, nose-like "beak" and the constrictions between its unusually large seeds -- two seeds in this pod -- at http://www.backyardnature.net/n/13/130331ch.jpg .

Behind the silique in that picture you see the stems, or pedicels, of flowers that have fallen off, having produced no fruits. I'm guessing that those flowers aborted because during the cold days of their flowering they didn't get pollinated. Farther up the raceme where flowering occurred during warmer, more recent days, every flower is setting fruit.

Radish siliques are exceptional in the Mustard Family in that they do not split open to release seeds when mature.

*****

MYSTERIOUS ORANGE SLIME UPDATE
In March of 2009 in southwestern Mississippi one morning my friend Karen and I were hiking in the sandy bottom of a deep ravine, or bayou as they're called there, when we came upon a wild Muscadine grapevine at the ravine's edge, from which a slimy, bright orange, jellylike substance clung to the grapevine's stem, as shown at http://www.backyardnature.net/n/09/090309of.jpg.

I didn't know what it was but I guessed that it must be a fungus or slime mold. When I sent the picture to mushroom guru Tom Volk at the University of Wisconsin and he had no idea, either, I asked readers for help.

Years passed, several people in the Deep South found similar orange slime and wrote asking me if I'd ever figured out what the slime was. Such a letter arrived this week, sent by Mark Musselman, Education Director at the Audubon Society's Francis Beidler Forest in South Carolina. For, it's March again, and the orange slime is appearing all across the Deep South. We both set about chasing the identity again, and eventually Mark stumbled upon a forum at the Mushroom Observer website where someone referenced an article in the Journal of the Mississippi Academy of Sciences, dated April 1, 2003 and entitled "The occurrence of Fusarium merismoides var. chlamydosporale (Tuberculariaceae) in Rankin County, Mississippi." The article referred to a "very wet, brilliant orange mass growing on a wild grape vine."

On the Internet, pictures of Fusarium merismoides seem to match ours.

Since that paper was published, Fusarium merismoides has been switched to the genus Fusicolla, so we can say that our orange slime is being produced by FUSICOLLA MERISMOIDES -- which, by the way, all along has been known by backwoods Southerners by the name of Deer Vomit.

But, it's not as simple as that...

In 2011 at the Fourth International Barcode of Life Conference in Adelaide, Australia a poster was presented on "The International Tree Slime Project DNA barcoding of fungal volcanoes." Fungal volcanoes! That sounds better than Deer Vomit, I must admit. And there it is stated that "Fusicolla merismoides (family Nectriaceae) is often considered the definitive tree slime fungus. This appears to be a large complex of many phylogenetic species. Almost every strain barcoded to date has a different sequence."

So, the fungus causing our orange slime/Deer Vomit/fungal volcanoes on Deep South grapevines apparently is actually several fungal species. Well, you can read all about it in a PDF document that can downloaded for free at http://www.dnabarcodes2011.org/conference/program/schedule/treeslime.pdf.

In that document you can also see a tremendous example of orange slime -- called slime flux there -- on a dogwood tree in Japan.

*****

FEATURED ESSAYS FROM THE PAST:

"Sleep," from the March 10, 2008 Newsletter, at http://www.backyardnature.net/n/p/080310.htm.

"Slugs, Snails & Mu," from the March 11, 2006 Newsletter, at http://www.backyardnature.net/n/p/060311.htm.

*****

Best wishes to all Newsletter readers,

Jim

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

Visit Jim's backyard nature site at http://www.backyardnature.net