A Little Salt in the Thorn Scrub

(A Continuation of “From La Sal Vieja to La Sal Del Rey”)

We drove from La Sal Vieja westward to La Sal Del Rey (“The King’s Salt”), which is another part of the Lower Rio Grande Valley National Wildlife Refuge. La Sal Del Rey refers to a shallow lake sitting on salt deposits, which make it ten times more saline than ocean water. Clint and I visited this place some years ago, on a searingly hot summer day that had us staggering back to the car, desperate for water.

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Sign within the refuge

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In contrast to the first photo, this one shows that the thorn scrub can be pretty impenetrable.

This mid-October day was far more pleasant. The sky had been clearing, and by now it was a sunny, warm day, with a breeze that kept things comfortable. The first part of our walk took us past mostly open mesquite woodlands with thick grass and huge prickly pear cactus growing in mounds sometimes standing well over head high. Other plants and trees included the ebony blackbead, tepeguaje, and a bush that appeared to be some sort of acacia. This latter plant seemed to be an invertebrate Mecca, attracting all manner of invertebrates. Clint found a pair of stick insects, the female perfectly camouflaged as just another gray branch, and the male more spindly and with green color, as would befit a thinner new shoot off the main branch. There was a large predatory wasp with a red abdomen that never would sit still for a photo and kept flying off, only to return shortly to this apparently irresistible bush. Scattered among the branches were the little ailanthus webworm moths, with folded wings looking like a mosaic of orange and yellow edged in black. There was a mesquite borer, double-banded longhorn beetle, and mantid flies. Snout butterflies fluttered among the branches. And growing fat among this buffet of insects was a green lynx spider that had pounced on some sort of colorful fly which was now being drained like some dipteran Slurpee.

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Stick insect, female

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Stick insect, male

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Green lynx spider with fly

We arrived at the lake and I walked up on the observation deck to see the broad salt flats shading into the lake, with a large group of sandpipers milling around at the water’s edge. It was like a glimpse of the beach in microcosm, only the water was undisturbed by any wave or movement. The birds presumably were poking in the sand for prey. I approached, and at one point they spooked, briefly flying in a tightly coordinated group, quickly returning to the wet sand to continue their activity.

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Scrub, then salt flats, and finally the lake

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Sandpipers

 

I walked out over the salt-crusted sand and silt toward the water, in places crunching on a glittering deposit of salt. I approached the sandpipers, which shuffled about nervously but did not fly away. Several of their group hopped about on one leg, like little one-legged pirates. My reaction to the first bird that did this was a concern that it had lost a leg and was forced to hobble about with his brethren. Then I saw that it appeared to be a habit among numerous members of this troupe, and I was less concerned.

Walking back from the bare salt flats into scattered vegetation, I wondered what could live in the salty, bare sand, in many places under a brittle glaze of salt. I took a photo of one of the principal plants which appears to be a saltwort, with succulent little fingerlike leaves, pale green or blue-green toward the top but pinkish toward the base.

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Silver argiope

Walking back, I spotted a kind of argiope spider sitting in its web constructed in a clump of prickly pear cactus. Clint identified it as a silver argiope, a more southern resident that barely crosses into the United States. It has the basic argiope or garden spider form, but its abdomen has some projections that were fairly subtle in this young one but Clint says become more pronounced in adults.

We did see a couple of whiptail lizards, and the second, tiny one reminded us that this year’s eggs have fairly recently hatched. We saw lizard scat, suggesting that there were many other lizards we did not get a chance to see. But our walk had been a pleasant one filled with invertebrates of amazing form and color, sandpipers, and a pair of magnificent caracaras soaring over the thorn scrub.

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