A Thanksgiving

We humans often depend on opposites for our frame of reference. We are glad when we feel well because we know what it is like to be sick. We cherish those we love because we have known loss. And so, in a time of fear and uncertainty, the things we are thankful for come into sharp focus. There are things that seem essential to us, which may be lost, and we hold them all the closer because we know how few promises we have about tomorrow.

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Mary’s Creek

When it comes to the natural world, I am very thankful for Mary’s Creek after spring rains, when the water runs clear over layers of pale limestone, and the sun shines a radiant blessing on the fresh green growth. The place has nurtured and sustained me for over fifty years, on and off, with its amazing community of living things. I have waded the creek in the happy company of friends, and I’ve walked it alone in quiet appreciation, and it is a comfortable old friend. I am also thankful for that place on still autumn days when the sun is bright but shadows are long, and you can watch a cottonwood leaf slowly float along the surface of a pool.

I am also thankful for the Fort Worth Nature Center & Refuge, a place I have also counted as a sort of second home for around fifty years. Every walk down the trail through the oak woodlands is a renewal, and every time I make my way down the old road through the bottomlands is like going to church. It is like church in its quiet strength, a place where one can reflect and be at peace among the tall trees. This is especially true in the winter, when the multicolored carpet of leaves and maze of tree trunks creates visual patterns of great beauty. Occasionally a crow breaks the stillness with a caw that echoes through the woods, and if you are lucky you might see an owl.

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The old road through the bottomlands

There are so many natural places in Texas, and I count myself very lucky to have visited so many of them. If I gave thanks every day, it would hardly seem sufficient for the days and nights spent in the Big Bend, seeing Palo Duro Canyon on a hike up the Rock Garden trail, walking through the Big Thicket, wading the headwaters of the Guadalupe River, and many other experiences.

And I have been very fortunate to have been in good company on many of these trips. Steve Campbell was a good friend to be in the field with, and many of us miss him greatly. Clint King is the little brother I never had, and finding such a like-minded, skilled and trustworthy field trip partner is a very great gift.

We have our time to explore, try to understand, and do our best to protect these places, and one day it is time for a new generation to inherit the land. Will they see what we see, and love what we love? It is a fervent, desperate wish that, having done what we can to share and teach, young people will be ready to be stewards of those places in nature that remain. We have lost a great deal; for example, only a tiny fraction of real tallgrass prairie can still be found, forests are cleared for pastureland, and oil and gas wells are sprinkled over more and more of the state. Relentless population growth and desire for energy and money threaten the plant and animal communities that sustain life. Nature needs people to fight for it, with their time, their voices, and their contributions. Today more than ever, it seems that we need more people than we’ve got, with more time and energy than we can spare, to keep the losses to a minimum.

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A view from the Lost Mine Trail, Big Bend National Park

And so, I am especially thankful for the bright and curious young people whose sense of wonder will keep them connected to nature. I’m thankful for Symantha, whose enthusiasm is impossible to resist and whose devotion to wildlife helps me have faith in the future. Likewise I’m thankful for Embry, who knows how to appreciate mosquitofish trapped in a pool and who confidently found much to love in a walk through the woods. I am also very grateful for Clint’s son, Zee, who has his parents’ passion for the natural world and who I’ll bet will be a fearless advocate for nature.

This Thanksgiving, I have a lot to be thankful for, and my challenge is to remember how fortunate I have been and how lucky we all are to be able to walk through a prairie or wade through a creek. Our public lands are still there, and a good number of talented people are still employed, for now, doing what they can to maintain, restore, and protect those places. I intend to keep getting out there, and will be thankful for each additional year in which we have preserved what we can of the forests, wetlands, deserts, and grasslands.

The Coleopteran Gold Rush (…and a chameleon of a beetle)

It was a sunny day in late October, and so I decided to take a brief drive over to the bridge that overlooks the west fork of the Trinity River for my lunch break to see if any interesting invertebrates were hanging out along the public right-of-way in the tree line that skirts the edge of a large tract of bottomland cross timbers forest that is owned by the city dump.  I know, this sounds like a terrible place to try to get away and enjoy nature, even briefly, but in all actuality it is not as bad as it sounds.  I have never seen the gate to the entrance to the place unlocked, let alone open.  Shut out the picture in your mind of some obsessive bug nerd peering into the low bushes with a stinking mountain of refuse in the background, blocking out the sun.  This is just an overgrown meadow lined by stands of sugarberry, bumelia, and honey locust conjoined by inseparable tangles of greenbrier, ampelopsis, and wild grape.  Above them stand their rightful elders: red oak, blackjack, ash, pecan, and willow.  A single patriarchal ancient cottonwood stands in the midst of this line of these mixed ranks of native hardwoods, its skeletal branches, devoid of leaves for several years now, still reaching up to the sun that no longer provides the dried, fibrous trunk with sustenance.  Red bellied woodpeckers and blue jays dart among the canopy above.  Occasionally a majestic blue heron wings by overhead en route to the nearby riverbank for an anticipated leopard frog lunch, its call a deep, guttural chortle on the autumn wind.  Gray treefrogs cling to the lowest branches of the trees as if they had been glued there.  They are so abundant I almost never fail to see one whenever I visit.  Great spotted purple butterflies compete with phaon crescents, eastern tiger swallowtails, and a host of other native butterflies among the low-growing lantana around the T-posts of the fence.  No, the west fork fringe of roadside around the “dump grounds” is actually not such a bad place to be.

The main reason I had been coming here for going on several weeks now had been to beat the lowermost branches of the trees for an exquisite member of the family of jewel beetles known as Buprestidae.  And in spite of all the good real estate (Buprestids as a general rule are fond of dead and – especially – stressed and dying trees) the species I had in mind was found in a slightly different microenvironment: the lowly sugarberry tree.

The sugarberry tree is a great thing, especially when you happen to be a buprestid beetle of the genus Agrilus and of the species macer.  At around ½ inch in length, with an oddly narrow, deeply crevassed elytra that appears to be spray painted gold in the sunlight, one would think they would be relatively easy to spot, but one would be wrong.  When sitting motionless in the dappled shade that filters in between the compound leaves and thin, drooping branches of the sugarberry tree in the bright noon sunshine, Agrilus macer blends in superbly and surprisingly well, so much so that they are practically invisible unless one happens to move.

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Agrilus macer

With beating stick/butterfly net and a white sheet stretched taut across an “X” shaped wooden frame, I set out across the tree line, my heart set on adding what would only be my fourth specimen of this unique species to my insect collection.

I found a tree fairly quickly, its unmistakable chaotic corking limb formation seeming to sprout from its short, twisted trunk from all angles, like a crop of wild hair.  Sugarberry trees are in the family of elm trees Ulmaceae, a huge genus that also includes such common natives as the slippery elm and American elm.  Aesthetically they are not too appealing, at least not compared to some of their more park-popular kin, but to a hungry macer they are the center of the universe, the wellspring of life, where the beetle’s entire life cycle is played out on and in the branches and trunks of the tree.

I placed the beating sheet (as they are collectively called among us bug brains) beneath the tree and gave the outermost branches a few sharp raps.  The goal of this endeavor (which I am certain appears to highway passersby as odd behavior) is to dislodge any invertebrates which may be residing there.  Although it sounds kind of droll, to a beetle or spider or caterpillar enthusiast (of which I am all of the above), it is like playing Mother Nature’s slot machine, and many previously undescribed species have been discovered in this manner, whereas they would otherwise have most likely gone unnoticed.

The slot machines are particularly loose between early June and late August, when most of our buprestid species are in the midst of their emergence and subsequent breeding season.  So yeah, it was a bit late in the year to have expectations set so high as to find one, but the weather sure was more desirable this time of year, as mid-June at high noon on the river floodplain can be one miserable place to be, beetles or no beetles.

The sugarberry produced no macer, although it did produce an emerald green nymph of the predatory pale green assassin bug.  A stand of willows grew at the base of a large, gnarled elder of the same kind.  The flaky, shingled bark is considered a delicacy to the handsomely marked willow long horn beetle, so I thought, “Why not? It’s not Agrilus macer, but it’s worth a shot.”

The first whack of the branch displaced a half-dozen shield bugs, flat, dime-sized pale yellow-green insects with constantly twitching antennae.  While shield bugs as a whole are among the most common of finds on the beating sheet, I had never encountered this particular species before, and so I collected a small series of specimens to study (and hopefully identify) back at home.  The next few strikes to the branches produced more and even more of them.  Their abundance here is a testament to their extraordinary camouflage, as I was unable to visually pick out so much as a single bug on the tree with my naked eye.

Another interesting willow connoisseur that ended up on the sheet in the aftermath of my assault was a stout, blue-green caterpillar around two inches in length, its body bespeckled with a generous sprinkling of raised pale flecks, as if it had been lightly dusted by a can of white spray paint.  The head had a strangely slanted, angled appearance, and the creature’s posterior end bore a curved, wicked-looking (though harmless) sickle of a horn.  This was the larvae of the twin-spotted sphinx moth, a pretty species with underwing eyespots of blue inside pink.  Although a few adults had turned up at my black light earlier in the summer, this was the first caterpillar I had found of the species.  These belong to the family of moths known as Sphingids, or hawk moths, so named for their body shape, when, with wings at rest, somewhat resembles the form of a diving raptor.  While the majority of hawk moth larvae are specialist feeders on vines in the grape family, a significant number of species feed on various hardwoods.  Like Agrilus macer, each species is usually fairly host-specific, and the twin-spotted is no different, feeding mostly on trees in the willow family.

I almost didn’t see it.  In fact, I didn’t at first, but as I knelt down in front of the sheet for closer inspection, there sat something remarkable, looking so out of place among the greens and browns of dislodged foliage that it didn’t even appear real.  Between two long, thin willow leaves sat a tiny beetle, barely 1/8 of an inch in length, that looked as if it had been dipped in solid gold.

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The golden tortoise beetle

I knew its identity the moment I laid eyes on it: it was a golden tortoise beetle, Charidotella sexpunctata, a species that had been immortalized in one of my favorite childhood field guides.  The specimens in the plate photograph had been taken in Arizona, and the range had simply read “Arizona.”  So I had made absolutely no effort to find this species in the field.  And yet here it was, amidst the torn greenery of a common sand willow in the company of sphinx caterpillars and scuttling shield bugs along the banks of the Trinity.  Talk about a range extension!  (I learned after some research that the beetle’s actual range is much broader, and that it is well documented in Texas.)

I fumbled in my pocket for a vial, and as I gently scooped the creature inside I noticed another beetle of identical shape and form as the first, except this one was colored orange with black spots, much like a ladybug.  Into the vial it went as well, along with a sprig of willow to make them feel a bit more at home.

By this time I figured I had better get back to work (the kind of work that actually pays my bills) and so I slipped the vial containing the two tortoise beetles into my pocket and headed for the truck.

Later that afternoon I picked my son up from school, and as soon as he climbed in I handed him the vial.  “Check out these tortoise beetles I found at the river today,” I exclaimed.  “One of them looks like it has been painted gold.”

Zee held the vial aloft, squinted, and then flipped open the lid for a closer examination.  “This bug isn’t gold-colored, but it is pretty,” he commented.  “Metallic purple!”

“What?!” I cried, “you’re crazy, kid! Let me see that!”

Sure enough, one of the beetles still looked like a flat ladybug, but the other was now exactly as my son had described it: a shimmering, shining light purple.

“It changed colors!” I said with a shout.  I imagine I felt not unlike the first Native American that had laid eyes on the green-to-brown pigment shift of a green anole.

Later that evening, my wife balked at the mention of this newfound phenomenon.  “Sure,” she said.  “Color changing beetles…far out, man!”

“I can prove it!” I retorted, and went for the vial.  Again I was in for a surprise.  The gold specimen turned purple specimen had gone through yet another color change!  This time its elytra appeared a soft baby blue.

At the moment I thought I had stumbled onto some incredible scientific discovery previously unbeknownst to the world of insects, but of course a little research into the natural history of this species (this time from a much more reliable field guide) explained how the golden tortoise beetle changes colors for a number of reasons, including its developmental stages, while breeding, and especially in response to foreign stimuli, where the beetle feels stressed or threatened.  This is apparently accomplished through the hydration and dehydration of the elytra, which is layered with a series of tiers of varying thickness.  These layers themselves are composed of even smaller, groove-like layers.  Each tier reflects a different color of light.  The three together produce gold, but when drained of fluid the bottom-most layer (a dull reddish-brown) fills the otherwise transparent wing covers.  The grooves also smooth when hydrated, giving the insect a shiny, metallic appearance.  Deprived of fluid, the shine quickly fades, giving the beetle a comparatively lackluster appearance.  So far this species and a single South American species of tortoise beetle are the only organisms known to science that change colors in this manner.CK-golden tortoise2

While I had failed to find the coveted Agrilus macer, I had come away with a beetle even more golden and (at least in my experience) less commonly seen.  While I hadn’t exactly made any new earth-shattering discovery in the world of entomology, I had experienced a fascinating aspect of the natural history of one of our state’s most beautiful and overlooked species first-hand.

On a side note, being the ever-obsessive beetle head that I am, I returned the next day to this same location to see if I could turn up any additional specimens of golden tortoise beetle.  I didn’t find any, but in a moment of irony I took a whack at a scrubby looking little sugarberry on the way out and to the sheet fell a splendid little gold-dusted buprestid, Agrilus macer!

The Austin Greenbelt Crowd

Barton Creek meanders through Austin before emptying into the Colorado river, and for over seven miles the corridor along Barton Creek is a popular greenbelt with a hiking trail. The creek embodies some of the best of the Hill Country – clear water running over limestone rocks and boulders, cliffs with maidenhair and other ferns growing from crevices in the rock, and juniper woodlands with scattered oak and other trees. And up in those trees live Texas’ largest lizard, the Texas alligator lizard. Although they can grow to two feet in length (including the tail), they are so well camouflaged that most people never see them. The other delightful reptile commonly found in the greenbelt is the eastern black-necked gartersnake. This might arguably be Texas’ most beautiful snake, or at least one of the prettiest. Clint and I have visited the greenbelt several times in the past, finding these two species and several other delightful critters.

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Limestone cliffs along Barton Creek

Austin loves its greenbelt, and it is lucky to have several small preserves and networks of nature trails. You could easily argue that such a big city could use quite a bit more than it has. With a population of 820,611, it ranks fourth in population among Texas cities. Evidently, many of those hundreds of thousands of people regularly visit the Barton Creek greenbelt, judging by Clint’s and my recent visit there. We arrived just before noon on a Saturday morning, met our friend Ruthann Panipinto, and headed down a break in the juniper woodlands to the trail that runs alongside the creek. Much of the Austin population was also running alongside the creek. And bicycling, and walking, and just seeming to be moved along en masse. It is a narrow dirt and rock trail, which we joined as soon as we found a gap in the parade of spandex and Nike-clad joggers, mountain-bikers constantly calling out to those in front so they could step aside, thirty-somethings with their dogs, and other folks.

We looked for any gap in the tangle of greenbriar, other vines, and tree saplings to escape the crowd, and used those opportunities to scan the leaf litter and rocky outcrops for gartersnakes, as well as trees above our heads for alligator lizards that might be draped along the branches. Were they here, despite the presence of all those people just a few steps away? Much of the wooded slope leading up and away from the creek is left alone by visitors, and it’s possible that wildlife become habituated to the nearby hikers if they rarely intrude beyond the screen of vegetation that borders the trail. We know that many animal species habituate to human presence, but how much does it vary by species and by size of the animal? To take one example, with repeated exposure to humans, alligators can “get used to” their presence, not fleeing when approached. However, not all species habituate to human presence, or not to the same extent. For the kinds of reptiles we were interested in, does it depend on how much disturbance occurs (can they begin to tolerate 1 hiker per minute, but not 40 per minute, for example), how close people are, and how often the disturbance occurs? We will have to leave those questions to the urban ecologists. We saw few reptiles and no amphibians, but it was the middle of an unnaturally warm October day, and there were millions of little hiding places, crevices in the rock, leaf litter, and piles of deadfall. Perhaps they were there, hidden.

We also dodged to the other side, to the creek bed, where it also seemed that visitors were uncommon. The clear water gently passed over the limestone rocks, as fish foraged around the bottom in graceful movements. A beautiful flame skimmer hovered, dipped, and darted around the area, and landed long enough for me to get a photo. These and other dragonflies are death on the wing for small soft-bodied insects that may be spotted by the dragonfly’s huge, wrap-around compound eyes. Like fierce raptors on cellophane wings, they intercept and snatch flies and mosquitos right out of the air. We watched this one for a while, and then returned to the trail.

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Flame skimmer

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Barton Creek

Back on the trail, the crush of hikers and joggers continued. Those on mountain bikes often had to stop and wait for traffic to clear, and to their credit, the ones I saw were patient and thanked people when they got out of the way. Nevertheless, the effect of all this reminded me of crowded lines at the Six Flags Over Texas amusement park. Should I be delighted that so many Austin residents love to get outside in this semi-wild setting? It certainly would seem elitist for me to wish them away, restricting this place to my little group and excluding others. I spend some of my time trying to educate and inspire people, encouraging a love of nature. Was this the kind of outcome we would see if all nature educators were wildly successful? Can wild places be loved to death (or to some kind of sickness)? And can I separate the spoiling of my esthetic experience from the possibility of a place being harmed? That is, just because I was not able to experience solitude, peace, and the undistracted appreciation of nature does not necessarily mean that the place is being harmed. It might be, but I would have to use a different measure than my personal reaction to judge whether the habitat is being degraded and wildlife being harmed.

It was time to leave, and we reached the entry point and started to climb up toward the street. We stopped for a moment, and Ruthann stepped away from the moving river of people and into the woods. There, at the edge of a small ravine, she spotted it. Stretched out on a short branch was an eastern black-necked gartersnake, maybe 10 or 11 inches long and likely born last year. She called to us to come and admire this colorful little serpent with the orange stripe down the back and zig-zag black spots down each side, above a cream-colored lateral stripe. After taking a photograph of it just where it was, Ruthann captured it and we positioned it for some additional photos, and then Ruthann released it to resume its wandering in the greenbelt.

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Eastern black-necked gartersnake

These gartersnakes are right at home along Barton Creek, where cricket frogs are common near the water’s edge and cliff chirping frogs are found along the limestone cliffs and outcrops. In my experience, these snakes are usually found close to a creek or some other water source, and this may be as much about diet as it is about the water and shelter offered by most wetlands. This snake is heavily dependent on frogs for its diet. A study by Fouquette (published in the Texas Journal of Science in 1954) provided information on the diet of gartersnakes found in Texas.  Of the black-necked gartersnake, most specimens studied were the western subspecies, but it seems likely that the results apply to the eastern variety as well. Fouquette’s study reported that one specimen regurgitated a red-spotted toad.  One preserved specimen contained a little brown skink (previously called the ground skink).  All other stomach contents consisted of frogs, except for one slimy salamander.

After we left, Ruthann showed us another location with public nature trails, and this one was less crowded. There are records of alligator lizards from that locality, and Ruthann pointed out a spot where she sees a resident black-necked gartersnake from time to time. Maybe this will be the place for us to visit in the Austin area. Barton Creek has many visitors, and perhaps the way we can do our part is to not add our own presence to the hikers, joggers, and bikers making the weekend trek to the greenbelt.