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

November 4, 2012

PORCUPINE
I'd never seen a porcupine, so on our full-moon walk this week maybe I can be excused for not immediately recognizing the car-killed bulk along the road. Illuminated only by the Moon, all I could see was its Raccoon size and odd silhouette, which was so broad that at first I thought it was a dead crow with outspread wings. But when I picked up the animal by its tail and felt its heaviness and stiff spines, it was instantly clear: it was the North American Porcupine, ERETHIZON DORSATUM. Pulling out the camera and opening the flash, I took the picture shown at http://www.backyardnature.net/n/12/121104pp.jpg.

To see what kind of feet porcupines have I flipped the animal over and took the picture at http://www.backyardnature.net/n/12/121104pq.jpg.

They almost look like skunk feet, but that's just incidental, since skunks and porcupines belong to entirely different orders. Skunks are carnivorans while porcupines are rodents. You might think that this is big to be a rodent, and it is, but porcupines are still smaller than capybaras and beavers, which also are rodents.

North American Porcupines are distributed from open tundra beside the Arctic Ocean in Alaska and northern Canada south through many kinds of habitats into northern Mexico, but they're absent from most of the eastern US, except for the Northeast. In Texas they're missing from the eastern and southernmost third of the state, but present elsewhere. It's a mystery as to why they should be absent from so much of the eastern US. The preferred habitats for Texas porcupines is forested areas with rocky areas, ridges, and slopes, which describes the limestone hill next to our walking road very well.

Porcupines are vegetarians and sometimes gnaw through tree bark to reach the softer inner bark, which damages the tree. They seem to have a passion for salt.

I told my neighbor Fred about our porcupine discovery and he wasn't too impressed, saying that they're pretty common around here. In fact, he sent me his picture of a porcupine clambering over a wire fence to get into his garden, which you can see at http://www.backyardnature.net/n/12/121104pr.jpg.

"He seemed to be enjoying the morning glory vines," Fred said.

*****

HOUSE FINCHES' CHEERFUL CALL
Being between breeding seasons, birds here are generally quiet these days, maybe the most noticeable calls being the hoarse, lusty croaks of the occasional Raven flying over the valley. However, on certain mornings when sunlight warms things up so agreeably, sometimes you hear a cheerful-sounding but soft and tentative, rambling sort of birdcall, perfectly harmonious with the morning's generous and benevolent sunlight. If you track down the calling, it's likely to be issuing from a bird and a place like that shown at http://www.backyardnature.net/n/12/121104fi.jpg.

That's a male House Finch at the very top of a Texas Live Oak with his chest fully against the sunlight. It's almost as if the warming sunlight were squeezing his warbling from him. Here's one description of the House Finch's song:

"To human ears, the keynote of all house finch utterances is cheerfulness. The song suggests happiness, and even the notes that express anxiety over peril to the nest have a cheerfully rising inflection. Entirely absent from their vocabulary are the strident bickering cries and harsh scolding notes that are so freely used by many other species."

Nowadays it's forbidden to speak of animals other than humans in terms such as cheerfulness and happiness, for it is anthropomorphic. However, I blame the manner in which our society is so hard on other living things largely on our lack of empathy with other living things, and sometimes a little anthropomorphism is needed to catalyze empathy. So, I indulge in it sparingly, and am glad to say that a House Finch's little warbling on a sunny morning is cheerful.

By the way, that quotation above, about the House Finch's utterances suggesting happiness, is from the Bent Life History Series of monographs published by the Smithsonian Institution between the 1920s and 1950s. As a kid on the farm in Kentucky, that's where I learned most of my bird facts, eventually owning a whole library shelf filled with nothing but editions of that series. Now the series has been incorporated into the Birdzilla.com website and I derive much pleasure by going back and reading how naturalists of earlier times were not only sharp-eyed, as they are now, but also unrepentantly anthropomorphic. You might enjoy reading their comprehensive treatment of the House Finch at http://www.birdzilla.com/birds/House-Finch/bent_life_history.html.

Here's another example from the Bent series:

"The building of the nest is accomplished by the female with little or no practical assistance from her mate, who, however, follows solicitously and lightens her labors with song."

*****

TURKEYS EATING GRIT
Someone has dumped a pile of limestone gravel at the edge of a field not far from the Dry Frio River, and at dusk Wild Turkeys go there and peck, as you can see in dusk's dim light at http://www.backyardnature.net/n/12/121104tu.jpg.

It makes sense that turkeys would gather there pecking, for they need sand or small gravel for their gizzards, which helps them digest their food. The mineral particles serve as "teeth" in the gizzard. It works like this:

The turkey swallows food and stores it in its crop if the food isn't needed immediately. Then the food passes into the "true stomach," or proventriculus, which secretes juices that help break down the food chemically. Then the food passes into the gizzard, also known as the ventriculus, where the gizzard's powerful and tough muscles grind the food with previously-swallowed stones. The food's next stop is the intestines, and then out.

All birds have gizzards, but not all birds swallow stones for gizzard grit.

*****

GROUND CRAB SPIDER
While painting a house this week I ran across a medium-size, orangish crab spider hanging on the outside wall with a partially sucked-dry caterpillar dangling from its mouth. You can see the whole thing at http://www.backyardnature.net/n/12/121104sp.jpg.

A close-up of the spider is shown at http://www.backyardnature.net/n/12/121104sq.jpg.

The spider's characteristic manner of holding its legs out crablike and the fact that no web was present made it easy to recognize this as a kind of crab spider, a member of the Crab Spider Family, the family Thomisidae. However, over 2,000 species of crab spiders are recognized, in about 170 genera worldwide, so recognizing it as a crab spider was just the first step.

Volunteer identifier Bea in Ontario figured out that our spider was one often called the Ground Crab Spider, XYSTICUS FUNESTUS, found throughout most of North America. Members of the genus Xysticus are known to hunt in leaf litter on the ground. The caterpillar looks like a kind of tent caterpillar, and tent caterpillars sometimes range across the ground looking for places to pupate, so one can imagine the drama that led up to the picture.

Crab spiders in general are noted for being able to move forwards, sideways, or backward. They have short, broad bodies and eight small eyes. Their second pair of legs is often heavier and longer than the third and fourth pairs. They don't build webs but rather prowl the ground and climb flowers and plants in search of prey. Many are spectacularly camouflaged, and often they take up position on flowers, their front legs spread out ready to grab whatever prey comes along.

*****

SYCAMORES WITH FRUIT-BALLS
Sycamores are common along the little Dry Frio River behind the cabin. When I first saw them I wondered if they were the same species I'm so familiar with in the East. I'm used to massive sycamores that can reach 160 feet high and higher (50m) and can have colossal, almost bloated-looking trunks. However, the ones here are the size of apple trees and bear leaves maybe half the size of what I expect on a Sycamore. Out West there are California and Arizona Sycamores, so I wondered if we might have a species like that. But, no, our trees are regular American Sycamore, PLATANUS OCCIDENTALIS, maybe just stunted by the arid conditions here, or maybe they're a small race adapted for this climate. Whatever the case, nowadays they're bearing fruiting balls, as you can see at http://www.backyardnature.net/n/12/121104sy.jpg.

A close-up of a dangling ball, a fruiting head, is at http://www.backyardnature.net/n/12/121104sz.jpg.

That ball is not a fruit, but rather a cluster of many fruits, each fruit having developed from a single tiny flower. Already some of the balls are breaking apart, especially where birds have pecked at them to feed on the fruits, which are achene-type -- dry, one-seeded fruits that don't split open when they mature. Among our birds the House Finches and chickadees seem to like them most. You can see three sycamore achenes, each with "parachutes" of stiff hairs arising from its base to help with wind dissemination, at http://www.backyardnature.net/n/12/121104sx.jpg.

I'm used to seeing American Sycamores with single trunks but normally the sycamores on the Dry Frio's floodplain produce several trunks. Probably they develop by sprouting from former trunks mangled by the Dry Frio's waters, which can rage when there's lots of rain upstream on the Edward's Plateau. You can see a typical cluster of trunks at http://www.backyardnature.net/n/12/121104sv.jpg.

While I had a sycamore before me, I thought I'd show you one of its leaves' unusual petiole bases, at http://www.backyardnature.net/n/12/121104sw.jpg.

On the branches of most kinds of trees, leaf petioles arise below the buds from which stems will arise the next year. Much in contrast to that, in the above photo at the top, right you can see how the Sycamore's petioles practically surround their attendant bud, hiding them. When the leaf falls, it leaves a slender leaf scar almost encircling the bud, as can be seen at the picture's left.

American Sycamores extend much farther west and south than here in southwestern Texas. In eastern and east-central Mexico they occur along streams atop widely separated mountains. There they are relict populations left there as the last Ice Age ended and plants of the Eastern North American forest biome migrated back north, or else found the cooler environment they needed by migrating up in elevation.

*****

CARNIVOROUS BLADDERWORTS
Along the little Dry Frio River behind the cabin in a shallow, muddy pool where someone has scooped out sand and gravel with a front-end loader, several fingernail-size, yellow, snapdragon-like flowers rise about 1½ inches (4cm) from the water on slender, leafless stems, as shown at http://www.backyardnature.net/n/12/121104ut.jpg.

Most flowers bear conspicuous conical extensions, or "spurs," like some orchid flowers have, which project forward beneath the broad lower lip, as shown at http://www.backyardnature.net/n/12/121104uv.jpg.

The flowers are bilaterally symmetrical, but with curiously raised, tonsil-like bulges in the throat, as shown at http://www.backyardnature.net/n/12/121104uq.jpg.

From above the population you can see that submerged in the water surrounding the flowers there's an extensive, much-branched system of leaves and stems as shown at http://www.backyardnature.net/n/12/121104uu.jpg.

If you pick some of the submerged parts from the water you see that the strands bear large numbers of bladderlike items averaging maybe 3/16ths inch across (2mm), as shown at http://www.backyardnature.net/n/12/121104us.jpg.

This is a wonderful, carnivorous aquatic called a bladderwort, genus Utricularia. I can't figure out which species it is. It seems to be closest to UTRICULARIA FOLIOSA, though it could be U. subulata. Both species are very widely distributed though seldom common, and certainly rare in Texas. So, this is a good find and it worries me that it's in a place where people dig gravel when they need it. I suppose the population became established there when a bird such as a sandpiper stopped at the pool and a bladderwort seed came loose from its body.

The bladderlike things in the last photo are traps for microscopic aquatic invertebrates. They are not air-filled and aren't used for floating. They are equipped with touch-sensitive hairs, called trigger hairs, that when disturbed cause the bladders to quickly suck in water along with whatever creature set off the trap. Digestive enzymes and bacteria in the bladder then digest the prey for the nutritional use of the plant, a process typically taking 15 minutes to 2 hours, depending on how large the prey was.

*****

CEDAR SAGE
We've run into several species of sage, genus Salvia, especially in Mexico, and now here's another, one that's very common here on thin, shaded soil beneath Ashe Junipers on our limestone hills. You can see it at http://www.backyardnature.net/n/12/121104sa.jpg.

A close-up of its bright red flowers is shown at http://www.backyardnature.net/n/12/121104sb.jpg.

This the Cedar Sage, SALVIA ROEMERIANA, one of several sage species found here. Some of the other Salvia species are blue flowered. The Cedar Sage's field marks include its habitat beneath Ash Junipers, its red flowers with especially long, slender corollas, and its leaves. Most of its stem leaves are more or less circular on long petioles, but its basal leaves tend to be pinnately compound.

As you might expect from a plant whose habitat is so dependent on an endemic tree -- the Ashe Juniper -- the Cedar Sage itself is endemic, in the whole world occurring naturally only in a handful of counties along the southern boundary of the Edwards Plateau, and into adjacent Mexico.

This is a very common plant on our hills, and a beautiful one, and to find that it's so little known outside our small area makes it a great find.

*****

FEATURED ESSAYS FROM THE PAST:

"Natural Paradigms," from the May 12, 2007 Newsletter, at http://www.backyardnature.net/n/p/070512.htm  

"Natural Spirituality Not So Complicated" from the August 30, 2009 Newsletter, at http://www.backyardnature.net/n/p/090830.htm

*****

Best wishes to all Newsletter readers,

Jim

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

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