Tag: amphibians

Wading a Desert River in the Magic of June and Nearly Bitten by a Rattlesnake

For the past twenty years or so, I have participated in a coordinated  volunteer project aimed at monitoring the presence of water along the length of the San Pedro River in southeastern Arizona. Organized by The Nature Conservancy, this project provides important data to scientists, land managers, and many others on the health of the river system during the hottest and driest month of the year. The data is collected the old-fashioned way – gathered by teams who experience the river in the best and most intimate manner possible, by walking and wading. Every June, I collect a portion of this data along a rare, perennially-flowing reach of the San Pedro located in the river’s middle valley, often accompanied by friends and neighbors. This year, two wonderful friends who also happen to be great neighbors assisted me in this worthwhile and delightful task.

Since June always brings oven-like temperatures, we began walking around 5:30am along a waterless stretch of the riverbed. Almost immediately, we discovered fresh tracks of an adult black bear and a cougar, etched in dry sand. One and a half miles in, the magic of water appeared. From that point on, the river flowed steadily. Because the brush is often nearly impenetrable along portions of the riverbanks, we waded, a much easier way to travel as long as one can avoid hidden lenses of quicksand. More mammal signs and tracks appeared; Coue’s whitetail deer, mule deer, javelina, coyote, bobcat, raccoon, coati, skunks, cottontail rabbits, mice and rock squirrels. Familiar bird songs spilled from the forest; summer tanagers and kingbirds, ash-throated flycatchers and song sparrows, southwestern willow flycatchers and black phoebes, grey hawks, tyrannulets, northern cardinals, Lucy’s and yellow warblers, and more.

The river in June is a different world from the surrounding vastness of desert habitat types – humid, verdant with profuse life, cool and shaded. It feels and smells almost subtropical. So much life graces the river and its forests in June that these annual walks have become my favorite time to explore and experience the beauty of the San Pedro.

Wading this desert river in the heat of June is magical. The cottonwood-willow forest stands tall and green, casting shade and coolness enabled by millions of fluttering leaves. The forest’s understory is verdant with lush growth. Eight-foot tall burr reed (genus Scirpus) plants crowd the riverbanks. Aquatic patches of speedwell (genus Veronica) glitter with multitudes of blue-purple blossoms. Tall willows form a vivid green arch overhanging the river. Birds sing from the depths of the forest, many butterflies, bees, and wasps drink from water’s edge, and scores of lowland leopard frogs leap at one’s every step. Below the surface, schools of long-finned dace are darting like shafts of animated light through the clear water. The continued presence of native frogs and fish are strong, positive indicators of the health of this aquatic ecosystem.

Among the most remarkable predators in the insect world, dragonflies are a common sight along the summer river. Some twenty-two years ago, an entomologist discovered nearly one dozen species of dragonflies and damsel flies that were new to science along this part of the river.

We waded for a couple of miles, feeling the warm, shallow waters of the river filling our shoes, until the waterway started to broaden and slowly deepen. I suspected a beaver dam was ahead. We climbed up on shore, then began to weave our way through a dense tangle of tamarisk and seep willow. Before long, we could see the beaver pond clearly, the water deeper and deeper, then the dam, plugging the river with a meter-tall, thirty-foot span of branches, twigs, tree limbs, rocks, and mud. I was elated to see that this reach of the river had beaver activity once again. The ecological and hydrologic benefits of beavers to this river – and many other waterways – are legion. I devoted an essay to this important topic in my book, The Life of the San Pedro River.

A cool, deep pond extends upstream of the beaver dam. Such dams hold more water within the river system, helping to recharge the aquifers that feed the river and its forest. The positive benefits of beaver ponds to plant life and many wildlife species could fill a book. Note the turbidity of the impounded water, a sign that the beaver(s) had been active there the night prior.

A moment of reflection seated atop the beaver dam before I was almost envenomated by a rattlesnake. Photo by Tom Talbott.

       My companions and I slithered down the steep riverbank to begin wading the final stretch below the dam. We had taken just a few steps when one of my friends suddenly threw his arm around me and pulled me out of harm’s way. A 3-foot western diamondback rattlesnake, coiled too close for comfort along the edge of the river channel, erupted in a frenzy of rattling. The forward third of the reptile’s body was off the ground and formed into an s-curve as the snake’s glistening black tongue waved slowly, curled backwards over its snout. Fully cocked, primed, and quite willing to strike. My fresh shoe print was about 14 inches from the rattlesnake. Had I not been yanked so suddenly by my alert friend, this snake would have probably tagged me. I have never come so close, despite encountering hundreds of diamondbacks here over the course of the last two decades. This experience underscores a crucial rule that I try to teach to everyone that I take into the wilds here – you should watch where every footstep is headed during the warmer months in southern Arizona! Sometimes, that is easier said than done.

This is the snake that I stepped far too close to, coiled, rattling, and very ready to strike defensively. Note the recent injury on its back, something that may have amplified its angry mood. If I weighed in at less than a pound or two, and a huge, towering, 200-pound bipedal mammal threatened to step on me, I’d be in a biting mood too.

Lightning Strikes 53 Feet From Me, a Deluge of Rain, Fireflies, Floods, and Images from a Wonderful Monsoon Season

The lightning bolt slammed into the ground with thousands of times the force and speed of a sledgehammer blow on an anvil. It struck so close to me that I heard no thunder, only the unmistakably loud, monstrously powerful  “snap” that is characteristic of a bolt that hits far too near to its observer. I had been sitting on my bed reading when it happened; I knew instantly what had occurred, for this was not the first time that lightning had struck so close to me that no thunder could be heard. Many years as a guide in the wilderness mountains of Montana had brought me into near-contact with lightning along high ridges at timber line more than a few times. It is one of nature’s most lethal forces when it strikes living creatures, but the other side of lightning is that it is one of the world’s most quintessentially important life-giving phenomena. For the full story, see pages 204-205 in my book, The Life of the San Pedro River. The next morning, I found the place where the bolt had impacted. A tape measure revealed that the lightning had struck 53 feet away. The electromagnetic pulse from that bolt fried our telephone system and our computer router.

The storms of this year’s monsoon season in southern Arizona have been wonderful – thus far, our rain gauge has registered 9.56 inches of rain since mid-June, resulting in a grand resurgence of life all across this hot and formerly dry landscape.

On the morning of August 20, a serious storm pounded the ground with so much rain that the area around our buildings became an unbroken sheet of water. I could hear toads starting to call  from our overflowing bird pond. Before long, dozens of spadefoot toads came out of their underground lairs to join in the party, all of them hopping and swimming through the flooded landscape in beelines toward the pond. This was a critical time for the amphibians, for in a normal year, they get only one or two brief chances to breed. It was also a rare sight, for I have never seen such activity in the daytime…but this was a doozy of a storm.

Mavis – the female half of the raven pair that we share habitat with – takes shelter from the storm under the roof of our shed.

As the rain subsided, I stepped outside. I heard the familiar roar of one of our local washes that had become engorged with flood water. A short walk of a quarter mile took me to a place where I could look down from the edge of a vertical cutbank at the flowing wash…

The view from the cutbank after 2.6 inches of rain from a single storm swelled Hot Springs Wash with roiling floodwaters. Only a single channel is visible in this image. The waters braided across the broad wash floor in an ever-changing – and growing – number of channels. Powerful floods are characteristic of desert washes with large drainage areas (this wash drains an area of about 100 square miles) and steep slopes in their headwater areas.

Next, I walked over to see what was going on in the little pond – there were eight pairs of Couch’s spadefoot toads in amplexus! A couple days later, after thousands of toad eggs hatched, our pond was teeming with wriggling throngs of tiny tadpoles.

Couch’s spadefoot toads mating in our pond. Each female usually lays hundreds of tiny eggs during such couplings, as the male releases sperm into the water.

After the mating frenzy, myriad spadefoot eggs clung to every blade of grass afloat in the water.

Later in the day, Kathleen and I walked down the road to have a look at where the big wash crosses the road. The sound of the flood grew loud as we approached a point where we could see the flow, over 300 feet in width. The dirt road – the only road that serves the entire valley – had become impassable once again. In the midst of the turbulent flow, where the waters ran deepest, trees were being tossed around like toys, ripped from their root-bound moorings as they sped downslope toward the San Pedro River. Hundreds of tons of sediment, gravel, and rocks were being transported toward the floor of the valley in a rip-roaring tumult of rain water.

A view of the flood as it obliterated the roadway where it crosses the usually dry bed of Hot Springs Wash. During the twenty summers that I have seen this wash respond to rainfall events, only twice have I witnessed it running larger than this.

As we were watching the floodwaters, I climbed to a higher vantage point, where I discovered this beautiful Sonoran gopher snake. The snake allowed me to gently approach within a foot or so. This was a fine specimen, over 5 1/2 feet in length.

A few hours later, the sun had melted down into the nether regions of the western horizon. My wife and I walked outside around 11:00pm to listen to the night sounds. After turning off our flashlights, we witnessed something that is seldom seen here – fireflies!! Few of Earth’s creatures are capable of instilling such an immediate and compelling sense of awe and wonder as fireflies are. They were emitting distinctive, paired flashes of remarkably bright green light – in so doing, they identified themselves down to the species level. We were seeing southwestern synchronous fireflies, Photinus knulli.

A couple of days after the big storm, I walked down to the San Pedro River. Many areas within the river’s drainage had received substantial rains, bringing the river to life. Here, el Río is surging along with a flow roughly 180 feet in breadth and over six feet in depth.

Downstream, a group of turkey vultures was roosting in a pair of dead cottonwood trees. Dead trees are an essential and important component of all forested areas on Earth. All too often, humans fail to recognize this aspect of our planet’s ecology. Our culture – embedded in the ecologically dangerous Abrahamic concept of land use – (the land is here to produce our milk and honey, for human use) – tends to see dead trees as “going to waste.” “Salvage logging” of our national forests after wildfires is an exemplification this anthropocentric view of our living world.

The rainy season brings twilight flights of thousands of buprestid beetles just above the canopy of our local mesquite bosques. Here, a very rare sight unfolds as a female Polycesta aruentis everts her ovipositor to lay her delicate eggs deep within the sheltering crack of a mesquite stump, where they will be out of reach of the sun’s touch. Her larvae will hatch to bore their way through the wood, leaving tunnels in their wake that greatly facilitate the entry of fungi and other agents of decomposition. Thus, insects like this play a critically important role in forest ecology.

A half-grown (about four inches in length) Sonoran desert toad enjoys our bird pond after a rain. These amphibians grow to prodigious sizes. If I am not mistaken, they are the heaviest toads native to North America.

Living in remote parts of the desert southwest demands some important learned behaviors. Only fools step outside without looking first. This diamondback had just finished crawling across my entry steps when I took this photo. Snakes of all kinds are always welcome on our property – but continuous caution when one ventures outdoors is an imperative part of living here.

A Lizard with a Voice and More Monsoon Discoveries

A reminder for my readers: Please do not read this in your email program. Instead, click on the blog title and you will be redirected to my web site for a much better experience with larger and clearer photos and text. You will also see the featured image that starts off every blog post, but (for some odd reason) is deleted from these automatically generated email notices.

A few evenings ago, an uncommon view from my desk window engendered delight and a deep feeling of gratitude. The scene encompassed a wild mesquite bosque, standing tall and green in summer’s refulgence…a gentle, drizzling rain was floating its way to the ground, suffusing the air among the stout trees with the magic of a fine mist, colored soft in fading light. The land was coming alive, replete with the promise of sprouting plants, emerging fungi, and the rising scent of moist duff. A water-borne resurgence of desert life was in the making.

During the past few weeks, more rain has fallen, resulting in a cavalcade of change, a water-borne eruption of desert life. Flowers are blooming and creatures are stirring, many of which cannot be seen at other times of year. Giant millipedes are crossing roadways and threading their way through the woodlands, tarantulas are out of their burrows roaming the landscape, harvester ants are forming great clouds of alates bent on their one-day-per-year mating spree. Sonorous calls of amphibian passion are ringing through the night after every substantial rain. “Monsoon” as locals know it, is the one season that defines these lands and the ecology of southeastern Arizona more than any other. Arizona without its monsoon would be akin to Alaska without a winter. 

One of many creatures that are revealed during this season is a small, nocturnal lizard with semi-translucent skin like gauzy velvet, big eyes with vertical pupils and movable eyelids, and the very rare ability (among lizards) to vocalize. Once encountered, the western banded gecko is not soon forgotten. More than once, I have heard the word “cute” applied to this beguiling little creature that rarely grows to more than four or five inches in length and remains hidden during daylight hours. 

I discovered this little gem sheltering under an old piece of plywood. This banded gecko had lost its tail sometime in the past – the new one grew back lavender in color. A plump tail like this one indicates a good state of health, for the tail stores fats and water for the animal to draw upon during lean times, much like the tails of Gila monsters.

When predators chase after lizards, the first part of the lizard’s body that they make contact with is often the tail. In evolutionary response to this, many lizards have developed special abscission layers in their tails. Once contacted, the tail breaks off, leaving predators detracted by a wiggling morsel while the main course absconds to safety. Banded geckos have tails that break off with a very, very light touch; hence, I recommend against handling them.

When threatened or disturbed, banded geckos often curl their tails over their backs. Such posturing mimics the scorpions that they share habitat with, potentially scaring off some would-be predators. Banded  geckos can also utter an audible squeak when frightened, making them one of the few lizards in the world capable of vocalizing.

During late July, the mass of tadpoles in our bird pond (see the previous blog post) transformed into toadlets in a matter of only ten days. The tiny young amphibians are now hopping their way into the surrounding woodland, disbursing at night when temperatures are cool.

This minuscule toadlet was photographed during its first day out of its natal pond, where it had spent the initial ten days of its life as a wriggling tadpole. At this stage of their lives, Couch’s spadefoot toads (Scaphiopus couchii), are tiny and vulnerable, fitting easily atop a mere dime.

On a warm early morning in mid-July, I took a walk and discovered an abundance of white-lined sphinx moths (Hyles lineata) almost everywhere I went. Most sphinx moths do their flying at night, but these moths were out in direct sunlight. They were specifically targeting wolfberry (Lycium spp.) bushes. The wolfberry was in flower, and the moths were hungry for nectar. With unerring accuracy augmented by  rapid, graceful flight, they were moving from flower to flower, hovering at each one to insert their long tongues for sips of nectar.

A white-lined sphinx moth hovers over a wolfberry bush, deftly inserting its long tongue into the tiny white flowers to feed on nectar. Note the bend in the moth’s tongue, a common trait among many species of sphinx and hawk moths.

White-lined sphinx moths have a very wide distribution that includes most of the United States. In some areas, their tongues are considerably shorter. Here, as they coevolved with certain types of nectar-rich flowers bearing long corolla tubes, their tongues adapted over time.

Since the first of this year’s summer rains on June 18th, we have received 4.25 inches of precipitation. Here is an image of our bosque taken just before the first rains.

The same area, photographed yesterday. The difference is clear – the greening understory is composed primarily of pigweed (Amaranthus palmeri), a native plant that is of great value to a wide variety of birds and mammals. If the rains continue, this vivd understory will be capable of reaching heights of six to seven feet.

This is what is left of a pigweed plant that grew after last summer’s monsoon rains. Pigweed retains much value to wildlife even after it has died and desiccated to a state like this one. Note that the plant has been recently fed upon, and that the cuts at the tips of each stem are sharply defined, cut cleanly at a steep angle. This is a signature left by the incisor teeth of a black-tailed jackrabbit. Nearly all rodents and lagomorphs (members of the rabbit order) leave such distinctive cut marks when they browse on similar types of vegetation. If deer or javelina had done this, the cuts would be rough with frayed edges and not cut at such steep angles.

Our area, the Middle San Pedro Valley, is served by a single dirt road that frequently endures serious damage after monsoon rain storms. I photographed this large wash near our home shortly after dawn, several hours after the flood had crested. The wet marks along either edge reveal a surging flow of flood waters that had crested at over 150 feet in breadth and four feet in depth. Flows this strong are quite capable of quickly carrying away almost any vehicle, even very large trucks.

An Early Monsoon Photo Gallery

This year’s monsoon got off to an early start in mid-June, but thus far, we have received just 2.98 inches of rainfall. Many storms have passed by, missing us by only a few miles. Hope for more rain is justified, however, because the summer monsoon season still has a couple of months to go. Summer rain always brings a wonderful blooming of life to this arid landscape, most of which cannot be witnessed at any other times of year. Here is a brief gallery of some of those recent gifts…

The floor of the local mesquite bosque has been bereft of greenery throughout the autumn, winter, and spring. One of the first substantial monsoon storms brought color to the woodland floor – an effusion of fresh, young plants erupting from the soil. Also visible in this image are mesquite pods. Millions of these highly nutritious pods have fallen from velvet mesquites in the valley during the past couple of weeks, providing a keystone food source for a tremendous variety of pod-eating wildlife.

Rain cleans and wets the ground surface, providing a crisp, fresh record of the presence of local wildlife, like this mule deer buck’s trackway. As is the case with most quadripedal mammals, these tracks show substantial dimorphism: the larger track represents a front foot, the smaller a hind foot.

The remains of a well-chewed mesquite pod reveal the place where a rodent fed the night before. This one was most likely the work of an Ord’s kangaroo rat.

Tarantulas remain hidden and mostly inactive during much of the year. Summer rains bring them out of their burrows. This is a full-grown (palm-spanning) male Arizona blond tarantula, Aphonopelma chalcodes.

If I am not mistaken, these are western subterranean termites, Reticulitermes hesperus. After the first strong summer rain storm, these insects emerge in spectacular swarms to embark on their aerial, one-day-per-year mating flights. Termites are among the most essential of all insects in the desert southwest, for they are primary decomposers of plant materials, recycling essential nutrients back into the soil.

A western diamondback feeding on a lesser goldfinch at our bird pond. Some people may find this image disturbing, but such a viewpoint implies an abiological bias…the cute little bird and the horrible, scary snake. Both are native residents of this ecosystem, both are equally welcome on our property, and both must eat to survive.

An ornate box turtle, Terrapene ornata, stationed itself under a suet feeder one day and revealed something new – box turtles love to eat suet! Bits and pieces fall to the ground as woodpeckers and other birds feed on the suet block; these high-calorie morsels are eagerly consumed by other creatures, including ravens and nocturnally foraging mice.

A heavy rain brought several Couch’s spadefoot toads to our bird pond. Females are typically colored with dark reticulations like this individual.

Male Couch’s spadefoots are usually much more plainly colored.

A first! This morning, our “bird pond” was wriggling with new life, a batch of spadefoot tadpoles! If these tadpoles survive to grow into adult toads, they will carry the memory of their natal pond’s geographic location, and will return to it to breed in future years.

Another first for our bosque – a Gould’s turkey with young in tow. I had seen turkeys here before, but never a hen with her offspring.

At dawn’s first soft light after a nighttime storm, there were a dozen or more white-lined sphinx moths (Hyles lineata) circling the small pool of water that constitutes our bird pond. The moths were alighting to drink – they disappeared soon after, as daylight strengthened. These are large insects with three-inch wingspans, equipped with powerful musculature that enables strong, rapid flight. This species ranges from Central American northward to Canada.

A Rare Pied-billed Raven, Giant Mites, an Insect Eruption, and a Tarantula for Dinner!

The four young Chihuahuan ravens that were hatched this spring in a  nearby mesquite tree have been exploring every nook and cranny of their expanding world. One of the four youngsters is a rare bird indeed, for it has a pied bill. (“Pied” simply refers to an object or creature that has two or more differing colors.) Both common and Chihuahuan ravens have black bills as adults. It will be interesting to see if this particular raven retains the pied colors on its bill as it matures into adulthood. The bills of its three siblings look quite different; they are well on their way to becoming fully black.

The young raven sporting a very unusual pied bill.

In comparison to any of its siblings, the pied-billed bird really stands out.

On the third day of July, this desperately parched, drought-stricken landscape received the first measurable rainfall in many months. Our rain gauge registered a total of 1.47 inches from two storms that arrived in the afternoon and late evening. Summer “monsoon” rains are an exceptionally important aspect of southeastern Arizona’s ecology. The summer rains spark a surge of new plant growth, enable many insects and amphibians to reproduce, feed the trees, recharge critically important aquifers, and much more. Life blossoms on this land after the gift of rain.

The “snowbirds” (part-time residents) who run out of Arizona every spring and scamper back in the winter never have a chance to experience the glory and magic of the famed summer monsoon season. So much happens in Arizona’s natural world during summer. Many creatures that are difficult or nearly impossible to see during the other seasons make special appearances during the monsoon. Among these creatures are red velvet mites.

Red velvet mites remain hidden underground during most of the year, where they seek refuge in silk-lined tunnels. Only after a summer rain do these giants appear on the surface of the ground.

The word “mite” should immediately conjure images of very, very tiny creatures. Most mites measure under a millimeter in length. Velvet mites (classified in the family Trombidiidae) are among the world’s largest mites. Some species approach one half inch in length; the one in the photograph is about a quarter of an inch long. They are nearly impossible to miss, as their brilliant red color contrasts sharply with their surroundings. Mites are very important constituents of soil fauna and thereby play essential roles in many terrestrial ecosystems. Some mites even have a place in human medicine. Oils extracted from one species of velvet mite native to India have been traditionally used to treat victims of paralysis.

photo caption: An emergence of thousands of winged termites from a gap between two cement slabs on the morning of July 4th, just after our first summer rain.

Every summer, on the first morning following the first substantial rainfall, termites erupt in synchrony by the millions from their subterranean dwellings in a united, landscape-wide orgy of reproductive zeal. Winged males and new, winged queens flood from their underground homes to take wing, mate, and disperse across the land. This event is one of spectacular importance, for termites are among the most essential and beneficial creatures in this entire desert ecosystem. They are primary decomposers, able to break down cellulose and thereby recycle plant materials into the soil. Without them, the health of this living landscape would be in serious trouble.

A closer look reveals a mass of gossamer-winged termites – new queens and males – known as alates. They arise from these masses in great numbers like curtains of smoke, dispersing, mating, and flying off to start new colonies. After mating, the insects lose their wings, structures that evolved for the sole purpose of dispersal and genetic interchange.

Monsoon rains also bring many other creatures out of hiding. Tarantulas are common here, but they are not easy to find except during the summer, when rains stimulate them to leave their burrows in order to forage and find a mate. These huge spiders are formidable, armed with a pair of long, sharply hooked fangs and stinging hairs on their abdomens. It is hard to imagine eating a spider that is large enough to fill the palm of one’s hand, but there are a few brave creatures here who regard tarantulas as dinner items…

Sonoran desert toads are common valley residents here along the San Pedro River. They are the largest toads native to the United States, reaching lengths of nearly eight inches. This rare image was photographed by a friend as the toad was in the process of ingesting a daunting meal, an adult tarantula.

There is more to the above  photograph than meets the eye. Frogs and toads possess remarkable viscoelastic tongues that fire from their mouths with great speed to catch their prey. Their tongues have a unique saliva that is phenomenally sticky; so sticky that some frogs in the genus Ceratophrys can haul in prey weighing more than themselves. This brings forth a question: how does a frog or toad get the prey item off of its sticky tongue once it is inside the amphibian’s mouth, so that it can be swallowed?

Alexis C. Noel, a Georgia Tech Ph.D. student specializing in biomechanics, published a scientific paper in 2017 documenting her research on the remarkable attributes of amphibian tongues and their saliva. What she discovered is physically, chemically, and biologically amazing…

Frog and toad saliva is a non-Newtonian fluid; the viscosity of the fluid can change based on how it is moved. When a frog’s tongue extends to impact a prey item, the saliva changes to a much more watery consistency, so that it can very rapidly coat the prey item and adhere to every part of the prey. As the impact slows to a stop and the tongue retracts into the mouth, the saliva returns to its normal thick, goopy consistency. This all happens in fractions of a second with incredible speed.

I recall watching many frogs and toads consume food items, mostly insects. Once the tongue returns inside the mouth with the prey item, the frog or toad retracts its eyeballs into its oral cavity, pushing the prey against the tongue. The push helps to release the prey from the tongue so it can be swallowed.