The Middle San Pedro Valley sprawls across nearly one million acres of undeveloped, unfragmented land in southeastern Arizona. Its slopes and woodlands, bajadas and ridges have been rimed with frost every dawn under the abbreviated touch of winter’s Sun. Days are short. The land stands hushed and still with its seasonal absence of many birds, reptiles, and other forms of life. Nonetheless, there are many good reasons to get outside and walk the land. January and February have brought a few surprises, particularly in the way of unexpected sightings of locally uncommon birds.
In late January, five purple finches began frequenting our bird feeders, thinking they were well concealed within mobs of house finches and lesser goldfinches. My wife’s sharp eyes picked them out of the crowd. In 20+ years of avian record keeping in this valley, that was the first time we had ever seen purple finches. Another species that has been sighted sparingly here during the winter months is the American robin. For reasons that remain a mystery to me, we have been inundated with robins this winter. They bring me many fond memories of their near-constant presence during past summers when I lived in the northern states.
Speaking of thrushes, another bird that I had never seen in the valley before has arrived to grace the nearby riverbottom woodlands this winter – a Townsend’s solitaire. A friend and neighbor, Tom Talbott, first sighted one about a week ago in the forests along the river not far from our home. Tom is a highly skilled birder and a masterful wildlife photographer. A few days later, walking the same reaches of the river, a friend and I also saw a solitaire. News has been spreading of numerous sightings of this species in areas just a few dozen miles to the north.
A Townsend’s solitaire perches quietly in branches overhanging the channel of the San Pedro River. These elegant thrushes are common residents of timberline forests high in the mountains of western Montana, where I would meet them again and again as I led groups of hikers during the summer months. Their songs are unique and unforgettably angelic, like no other bird I have known. Photo courtesy of Tom Talbott.
Not far from the solitaire, we found this great horned owl snoozing within the branches of a Fremont cottonwood. These owls are remarkably capable predators whose list of possible food items exceeds that of any other North American owl. Among the creatures that great horned owls have been known to prey upon include insects, amphibians, various reptiles, mice, rabbits, domestic cats, small dogs, ducks, skunks, and even porcupines.
Mid-January brought us over an inch of rain in the valley floor during one winter storm. Rainfall amounts were much higher in the nearby Galiuro Mountains, resulting in a strong winter flow for Hot Springs Wash. Such flows during the winter months are rare.
The rain enabled millions of dormant London rocket (Sisymbrium irio) seeds to sprout, providing a new source of food for wildlife while greening the floor of this mesquite bosque with the glowing color of new life.
Large numbers of these small white puffballs erupted from the ground under mesquite trees after the rain. Fungi are becoming known as some of the most important organisms on the planet. The mycorrhizal filaments of many species of fungi form mutually beneficial associations with tree roots, for example. No forest on Earth can exist without such subsurface fungal alliances.
A hooded skunk wandered under my ramada one night, leaving its signature behind in the form of these tracks made in fine, dusty soil. Note the track pattern as the animal was walking at normal speed.
A closer look at the skunk’s footprints. Even though skunks are plantigrade mammals, the heels on their back feet often do not register in their tracks, as seen here. (The hind foot is to the left, front foot to the right.)
I discovered this torpid spiny lizard spending the winter brumating underneath a plastic tub that had been set outdoors on the ground. The lizard was found at ground level, not dug in below the frost line. Temperatures here routinely dip into the teens every winter. I was taught that reptiles must spend winters below the frost line, because otherwise they would freeze and die. I have also seen a pair of diamondback rattlesnakes spending the winter under a board in an open barn. Apparently, what I was taught cannot be correct – it seems clear that these reptiles can endure a fairly substantial amount of freezing.
Darkness settles over the land. Many miles from the lights and sounds of towns and cities, Arizona’s Middle San Pedro Valley sprawls wild and still. At twilight, only a faint poorwill and a pair of great horned owls can be heard. The coyote telegraph erupts and then fades as it travels from ridge to distant ridge. In contrast to the rich variety of summer sounds, an autumnal hush blankets the countryside.
At day’s end, dusk gently ebbs into darkness as a brilliant October moon emerges from the far shores of the eastern horizon. Here, in our mesquite bosque, the peace and comfort of the night suddenly give rise to a thousand voices raised in the jubilance of courtship. These are sweet, almost melodic sounds – October’s distinctive nocturnal biophony. Tree crickets are singing from the ancient trees, thousands of them spread across the valley floor, their songs a vivid proclamation of thriving life within an otherwise quiet forest.
This species of tree cricket sings from the tall mesquites in our bosque. Its ecology is intimately connected to velvet mesquite trees. These are small insects with a big voice.
I have come to love the sounds of these delicate, gossamer-winged insects. Long after summer’s insect frenzy, when most species have faded from the scene, tree crickets come to life in the coolness of October nights. The males raise their transparent wings, then call to the females by stridulating – in other words, they rub certain parts of their bodies together to produce a surprising volume of sound. Females are drawn to these love songs. The males go one step farther by offering their mates a special reward. After mating, metanotal glands located on the dorsal side of the male’s abdomen secrete a substance that the female feeds on.
Eight species of tree crickets inhabit southeastern Arizona, where they produce two generations each year. The ones singing in local October bosques belong to the genus Oecanthus. Each species has its own unique song. However, even among the same species, sound can vary quite a bit depending upon air temperature. The frequency (or pitch) of the crickets’ songs increases as temperatures rise and slows as temperatures fall.
A bizarre butterfly landed on my screen door last week – an American snout butterfly, Libytheana carinenta. Last year, large numbers of these butterflies erupted all over the valley in late summer. Snout butterflies use their strange shape to blend in with their surroundings. When perched on a plant stem, their elongated “snout” breaks up the outline of their bodies, resembling a broken twig or a thorn. The range of snout butterflies extends all the way to South America. They are known for migrating across landscapes in huge aggregations.
A study in camouflage, the American snout butterfly sports wings that blend well with tree bark and a unique body shape that helps to conceal the insect when at rest.
This summer’s plentiful monsoon rains have continued well into October. Since the monsoon began on June 18, our rain gauge has recorded an amazing 13.46 inches of life-giving rainfall.
One of the local washes experienced some large summer floods. I took a walk down this wash with a friend a few weeks ago, to have a look at the powerful changes wrought upon the land by the big floods. What we saw was in stark contrast to the wash I had known from walks during the past several years.
During recent times, this broad wash had been covered by a wall-to-wall effusion of burro bush (Hymenoclea) standing six or more feet tall with a galaxy of roots anchoring the bushes to the ground. The flood had erased most of that growth, leaving behind a clear streambed lined with heaps of debris – tree trunks, plant material, rocks, and more. The floor of the big wash had been totally rearranged, its topography and course markedly changed during a couple of events that lasted only days.
In places where floodwaters form swirling, circular eddies, holes are dug into the wash floor like this one. These depressions can be very large and quite deep. They often hold pools of surface water that can last for months after flooding, a valuable offering to birds, mammals, and other wild creatures in this desert ecosystem.
Powerful floods like these transport thousands of tons of boulders, rocks, gravel, sand, clay, and a wide variety of organic materials – whole trees, cacti, and other plants. Downstream, entire soil profiles are altered and built as sediments settle from the turbid waters. Cutbanks collapse, dropping great layers of soil into the roiling floodwaters, releasing seeds that have lain dormant from ancient times into the present-day ecosystem. Old genetics from times long gone may invigorate plant populations and enhance the genetic variability – and hence, the viability – of modern plant communities.
Most people would simply label this collapse of a stream-side cutbank as “erosion.” That is an accurate use of the word, but I see much more going on here.
Debris piles left along the stream banks can be very large, consisting primarily of tangled, broken bushes, parts of trees, and other plant matter. They provide shelter and denning sites for small mammals, reptiles, amphibians, and other creatures. Floods are not all bad – they are simply a natural, intrinsic agent of change, some of it beneficial, some not. People often label floods as “bad,” but that viewpoint roots in anthropocentric thinking, a myopic way to view our world.
The ecology of many native species of plants and animals actually depends upon flood events. The beautiful stands of cottonwoods that line the San Pedro River could not exist were it not for floods creating the specific conditions that their seeds require for germination. The riparian forests that accompany the river depend upon having their roots tap into subsurface aquifers. The aquifers get recharged when floods happen.
As floodwaters recede, the bed of the San Pedro River leaves records of local wildlife in the drying mud. Here, the patterning of fine surface cracks results from a place where the river water subsided very gradually with little or no turbulence, resulting in the deposition of extremely fine clay particles. As these clay deposits dry, they crack in characteristic patterns.
October typically brings us the last ophidian visitors of the year, most of them not to be seen until next spring. A beautiful gopher snake was here last week, and as I write this, a diamondback is curled up a short ways from my entry door.
An October gopher snake, crawling along the wall of one of our buildings. This one was a male, measuring right around 63 inches in length. Always welcome here, as are all snakes.The year’s last generation of pipevine swallowtail butterflies occurs in October. I found this gorgeous caterpillar recently – it is either in the fourth or fifth (last) instar of its development, after which it will climb a plant stem and metamorphose into a chrysalis suspended by a single loop of silk as it waits out the winter season. The leaves visible in this image are pipevine leaves, (Aristolochia), the only plant that these caterpillars feed upon.
October is THE month for seeing pinacate beetles (Eleodes spp.) – they are literally everywhere at this time of year, easily noticed because of their large size, slow movements, and diurnal habits. When they feel threatened, pinacate beetles stop moving and assume this head-stand posture. If the threat escalates, (for example, when a bird tries to grab the beetle), the beetles fire a noxious, very disagreeable fluid from the tip of their erected abdomen. Chemical defenses are very common among many insect species.
Just a few days ago, I noticed this small tuft of feathers laying on the ground. Immediately, I began searching the area for more, because such a find usually indicates that a bird was recently preyed upon somewhere nearby.
I soon found many feathers like this, their shafts intact. Intact shafts indicate feathers that were pulled out, not bitten and yanked out as mammals do. So this was the work of a predatory bird, likely a Cooper’s hawk that I have been seeing frequently of late. This was a special find, for these feathers could have come from only one species, a gilded flicker. Gilded flickers are relatively rare in local bosque habitats.
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.
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.
It has been a very long time since I posted a new entry on this blog. I feel that I owe my readers an explanation. Why no new blog posts? I have been deeply depressed for months – and depressed writers don’t write. In terms of what has been causing this lasting depression, it is a small avalanche of things…the unjustified furor over the most recent presidential election. The insurrection – one of the most unpatriotic acts I ever known to mar my country’s history. The widespread denial of science by millions of Americans. The pandemic – ranking the United States as the world leader in Covid deaths – an inexcusable national embarrassment. Mass shootings -another ghastly national embarrassment, as we lead all other nations on Earth by a very wide margin with respect to such violent, maniacal acts. The mounting gullibility of our populace coupled with a concerted effort by millions to divide a great nation. The horrific war in Ukraine…and there is plenty more, but I will keep the rest private.
As it has been throughout my life, the world of nature has been a source of peace, calm, reassurance, and sanity during these deeply troubled times. I am so grateful to live far away from towns and cities in a rural setting where birdsong, wildlife, a lack of crowding, and sunlight feed my soul.
So, what is going on in the Middle San Pedro River Valley lately? The landscape is very dry, even by desert standards. The usual winter rains were both scarce and weak, resulting in an entire region whose mesquite bosques sprouted no green understory plants, a valley floor bereft of the normal growth of winter grasses, perennial reaches of the river receding, and uplands nearly devoid of spring wildflowers.
The bright crimson fruits of Christmas cactus, Cylindropuntia leptocaulis, bring color to a desperately dry landscape. This species is of special benefit to wildlife, for it retains these nutritious fruits throughout autumn, winter, and into the following spring, even in a very dry year like this one. Indigenous peoples made common use of the fruits of this cactus as a food source.
As far as avian life goes, I have never witnessed such a paucity of birds here, both in terms of species diversity and numbers. Numerous migratory species, birds that I have regularly observed every spring for 20 years, simply did not appear, or appeared in very low numbers. There were no back-throated grey warblers, no orange-crowned or Virginia’s warblers, no Empidonax flycatchers. I recorded the presence of only one Townsend’s warbler during migration, and there were startlingly low numbers of normally abundant yellow-rumped warblers. Rufous-winged sparrows, a common fixture here, are entirely absent from our property this year for the first time ever. On the positive side of things, we now have three dazzling male varied buntings visiting our water dishes daily, two more than any other prior year had provided. Our resident ravens, Mike and Mavis, hatched out a clutch of four a few months ago, just 100 feet from my office window. That brood fell victim to a group of coyotes on the very first night that they left the nest. The determined parents have since built a new nest on a nearby property, a place where the landowner is very appreciative of the local wildlife. Mavis is busy incubating her second clutch of eggs in a safe place…
Even the local reptiles – especially the snakes – have been few and far between this summer. A few weeks ago, one of our local diamondbacks appeared at our bird pond to drink and grab a feathered meal or two.
This western diamondback – a familiar individual – appeared in May, visiting our bird-watering pond.I have come to recognize several of the rattlesnakes whose ranges include the area close to our buildings. My sharp-eyed wife pointed out the distinctive, fused blotches on this snake’s tail. With close observation, nearly all rattlesnakes can be recognized as distinct individuals – the patterning and shape of the blotches on the back, and especially markings on the heads and tails of rattlesnakes make it possible to readily identify individuals.I have seen diamondbacks lay in wait at the edge of our little pond, but very rarely do I see them partially submerged like this.
During the hot months in southeastern Arizona, any water source attracts wildlife of all sorts. Simply maintaining a few water dishes does wonders for throngs of very thirsty birds, reptiles, mammals, and more. Our “bird pond” is nothing more than a shallow depression dug into the ground, fed by a trickling garden hose; very simple to set up and maintain. It would take pages of text to tell all the tales of the remarkable diversity of living creatures that have availed themselves of this water source over the years.
Box turtles have come out of hiding. This one waded into the shallow pond to cool off and rehydrate itself via some long drinks.A herd of well over 20 javelina visit here daily – here a mother drinks water from the pond while her youngster suckles milk.
Last, but surely not least, as I began to assemble this new blog post on the evening of June 10th, raindrops began pelting the roof! This was no “teaser” rain, no ten-second-this-is-all-you-get rain, but a prolonged rain that wetted the dusty ground and left small puddles in its wonderful wake. This is a rare event, so early in June. Desert life benefits from the gift of every precious drop.
The 2021 monsoon season in southeastern Arizona has certainly been one of the most memorable. At our home acreage in the Middle San Pedro Valley, 9.81 inches of rain have graced the land since the rains began on the second day of July. Other locations within less than 40 miles of us have received over 16 inches! The result is a landscape – and an ecosystem – burgeoning with a refulgence of renewed life. Since regional records have been kept, only the 1955 and 1964 monsoon seasons can compare. The scene above, featuring a landscape bursting with fresh, vivid green growth crowned by a rainbow is emblematic of Arizona’s monsoon.
As the monsoon wanes, migrant birds visit our feeders and watering places; notable appearances this year have included large numbers of Nashville warblers and an exceedingly rare blue bunting, a species that has never been “officially” recorded anywhere in Arizona. As the season approaches autumn, many changes occur in the world of reptiles and insects as well. Rattlesnakes are moving toward their hibernacula sites. The year’s last generation of butterflies brings flashes of beautiful color to the ecosystem. Other insects are reaching maturity, such as several types of native grasshoppers and katydids.
During the past two weeks, great numbers of mature lubber grasshoppers could be seen in many places in the valley floor. Their presence and abundance are a reflection of the monsoon rains that have enabled an explosion of plant life – a smorgasbord for grasshoppers. At this time of year, these bulky creatures have reached their final instar and are actively seeking mates.
A mature lubber grasshopper, Brachystolla magna. It is normal to see large numbers of these heavy, slow-moving insects during the tail end of our monsoon season. Note the tiny vestigial wings – this grasshopper is incapable of flight.
In mid-August, just after an afternoon rainstorm, I watched a female ornate box turtle emerge from the bosque to drink from a rivulet of rainwater. As she was slaking her thirst, I caught a flicker of movement some forty feet beyond her at the edge of the trees. It was a male box turtle. He had spotted her, and this was mating season. If you think turtles are slow, you have never seen an amorous male box turtle chasing a female! There is nothing subtle about box turtle sex. The males literally run down and attempt to corner the females, who move nearly as fast in their attempts to elude the charging males. Once the pair is joined, mating can take upwards of an hour.
A male ornate box turtle in hot pursuit of a prospective mate. I have seen this happen a number of times; what is most amazing to me are the distances at which the males first spot the females when the chase begins. In relatively level areas with open ground, males can visually discern females located at least 30-40 feet distant. Once a female is spotted, the male immediately makes a beeline to her at top speed.
The chase ends with a successful mating, allowing the circle of life to continue as it has for countless millennia.
Last week, my wife Kathleen discovered a new species of beetle, (one we had never seen here before), floating in a rain collection bucket. She rescued the hapless insect – a gorgeous, iridescent creature known as the Carolina tiger beetle.
This glittering, multi-colored tiger beetle got a new lease on life when it was rescued from a full water bucket.
Tiger beetles are incredible insects. The have been a part of my life since boyhood, when I often attempted to catch them as they raced across the ground with what seemed like otherworldly speed. Very few insects are faster on land than tiger beetles. Tiger beetles are hyper-alert predators equipped with unusually long hind legs for rapid propulsion. Their big heads house a pair of huge compound eyes capable of acute long-distance vision. The visual field of a tiger beetle encompasses more than a full hemisphere. When a prey item is spotted, tiger beetles run it down, then secure their meal with a set of long, formidable, serrated mandibles.
A lateral view of the Carolina tiger beetle, Megacephala carolina.
Most species of tiger beetles are diurnal, but the Carolina tiger beetle is an exception, preferring to be active after dark. I wonder if any part of these insects would glow under a UV light source? A number of other local nocturnal creatures glow under ultraviolet light, including scorpions and pocket gophers.
Butterflies are often abundant during the monsoon. As I was working outdoors one day, I noticed a fresh chrysalis hanging from some old wire fencing. I recognized its form; it had been made by a caterpillar that was a member of the butterfly subfamily Danainae. Insect species native to Arizona that belong to this group comprise three look-alike species: monarch, queen, and soldier butterflies.
The chrysalis hatched in a short time – only a week or so – to reveal a gorgeous queen butterfly. After hatching, the butterfly clings to the shell of its empty chrysalis, pumping blood into its unfolding wings.
Once the butterfly’s wings have expanded to full size, it is normal to see the insect remain perched for some time as it slowly opens and closes its wings, readying itself for its maiden flight.
Many plants native to the desert southwest have specially adapted themselves in a variety of ways to the summer monsoon season. One of the weirdest, most bizarre, and fascinating is a plant known as dodder. The first time that I encountered dodder, I stared in sheer wonder for some time while thinking “what the hell is that?”
Patches of dodder are a common sight during the latter half of the monsoon season.
Dodder grows as a vine, commonly forming a scattered profusion of very fine, yellowish tendrils that snake their way through the vegetation. It is a plant that cannot manufacture chlorophyll. Dodder survives by obtaining water and nutrients from other plants – it is an obligate parasite.
A closer look at dodder, (genus Cuscuta).
The weirdness begins just after a dodder seed sprouts following a monsoon rain storm. The minuscule seed – nearly microscopic – sends a small, shallow root into the soil while raising a tiny, thin tendril above ground. As the tendril grows, it starts to turn in upwardly-ascending spirals. It is not seeking light as most plants do – it is searchingfor a host. As the tendril lengthens, its spirals correspondingly enlarge, until it makes contact with a nearby plant. The tip of the tendril is chemosensory; it can literally sniff out what sort of plant it touches. Dodder is selective about the company it keeps – only certain plants will do as suitable hosts. If the tendril likes what it senses, it wraps itself tightly around the plant’s stem, then sinks a feeding tube – known as a haustoria – into the stem.
At this point, the seedling’s tiny root dies. The dodder plant then obtains all of its water and nutrients from its host. It will continue to grow and search, attaching itself to more plants. Once it has inserted enough feeding tubes into its victim(s), dodder reaches a point in its physiology that enables it to reproduce. Clusters of tiny white flowers erupt from the vine’s stem, ensuring the plant’s future.
Our local species of dodder sprouts clusters of small, white flowers – these grew from a dodder vine that had entwined itself on the stem of a pigweed (Amaranthus palmeri) plant.
So what is truly bizarre about this parasitic plant? Research has documented the fact that dodder actually steals sequences of DNAfrom its host plants’ genes, then incorporates them into its own DNA. The process is called “horizontal gene transfer.” This results in better survival for the dodder plants. It also enables them to manufacture strings of RNA that it sends back into the host plant, causing the host to weaken its defenses.
Dodder plants are classified as members of the Convolvulaceae – the morning glory family – with over 200 species worldwide. The genus, (Cuscuta), has a global range, occurring in tropical, subtropical, and temperate habitats. Dodder has a slew of common names, many of them derogatory – strangleweed, witch’s hair, devil’s guts, scaldweed, devil’s hair, and hellbine.
When considering this plant, we should strive to avoid the common propensity of our species to pass judgement on other life forms….often the result of our high capacity for arrogance-as-a-species combined with ecological ignorance. Simply because dodder is a parasite does not make it bad. Estimates place the percentage of parasitic organisms on Earth at 40-50% of all species. Clearly, parasitism is an essential part of the recipe for life on Earth. Here in the Middle San Pedro Valley, one of dodder’s favorite host plants is pigweed. Even when heavily infested with dodder, local pigweed plants continue to grow and produce viable seed.
Arizona’s spectacular monsoon season is in full swing this year. Here in the Middle San Pedro River Valley, we have received 7.28 inches of life-giving rain during the past seven weeks. Life of all kinds is emerging, much of it empowered by this season alone.
The strikingly beautiful Gila monster pictured above was photographed by my wife Kathleen just days ago. (One more reminder to my readers: if you don’t see that image, it is because you are viewing this in your email. Always go to my blog site – https://ralphwaldt.com – to see this post as I intended it, without omissions.) It is one of many desert animals whose activity increases or otherwise changes as a result of monsoon weather.
The world we live in has been under deep duress this past year; the global pandemic, political division, economic hardship, and numerous worldwide catastrophes have all combined to make many people feel stressed and depressed. That is the anthropocentric world. A wider view – beyond the human-centric world that we pay so much attention to – encompasses the rest of the planet’s glorious and infinitely varied life. When I feel overloaded after viewing the day’s headlines, I can always find a source of solace, reassurance, and joy simply by abandoning the vicarious, shallow world of my computer screen in favor of the outdoor world. All it takes is a few steps outside. Sunlight, vivid green plants, lizards, trees, bird song, fresh air… the real world is medicine for the soul.
One does not need to live in a rural area like I do in order to tap into the natural world. I have a friend who lives in suburbia, along the fringes of the immensity known as Dallas-Fort Worth. He spends time in his backyard where trees, shrubs, and a garden bring life and happiness into his world. There are no bears, cougars, or Gila monsters in his yard like there are here – but there is a diverse variety of life. My friend focuses his attention on smaller creatures and other forms of life; insects, lizards, and flowering plants, for example. He photographs what he sees – things that most people never even notice. The photographs from his back yard are often stunning, revealing a world remarkably rich in life captured by a talented, artistic photographer whose sharp observational skills remind us that life is everywhere, and that life is beyond beautiful.
With those thoughts in mind, I offer a series of recent images taken during the heart of the monsoon season here in the Middle San Pedro Valley of southeastern Arizona…
My wife, Kathleen, encountered this Gila monster as it was attempting to cross a public roadway. She did the right thing – she pulled off the side of the road, turned on her hazard lights, and stood by, ready to usher the lizard out of harm’s way should a speeding motorist arrive on the scene. As the Gila monster made it safely off of the pavement, it turned to face Kathleen and her camera, then ambled off into the desert. The lizard was lucky this time. Large numbers of reptiles are killed on Arizona’s roads every day, many of them by people who are fast drivers and/or simply harbor callous attitudes towards reptiles. All it takes to avoid such losses is slower speed and a modicum of care for the life we share the planet with.
A single feather laying in front of our ramada had a story to tell: a great horned owl had landed there the night prior, likely as it pounced on a prey item.
Mornings that follow monsoon rain storms often reveal the nocturnal work of encruster termites. These tiny insects encrust plant stems (or in this case, mesquite beans) with a mixture of soil particles and viscous saliva, then feed on the encapsulated items. Termites are exceptionally important components of this ecosystem; they are very numerous, widespread, and perform a crucial ecological function by breaking down plant cellulose, thus returning essential nutrients to the soil.
Some two decades ago, I first tasted wolfberries – they were delicious. Native peoples gathered these berries as a seasonal food source. A large number of birds and mammals utilize them as a high-calorie-per-unit-weight food source, packed with natural sugars. This plant is of the genus Lycium.
Summer raindrops adorn the fresh blossom of an Arizona poppy plant, Kallstroemia grandiflora.
One of the valley’s most common summer wildflowers is also among its most beautiful; trailing four o’clock, Allionia incarnata.The emergent blooms of a barrel cactus. These cacti rely on summer rains for their annual reproductive efforts.
Silver-leaf nightshade – Solanum elaeagnifolium – always a joy to encounter, this native plant is grouped in the same botanical family as tomatoes, but it is not safe for human consumption.Tarantulas are common here, but can be seen with any frequency only during the monsoon season, when lower daytime temperatures and increased humidity bring them out of hiding. If left alone, these are harmless, innocuous creatures.
Caterpillars of the white-lined sphinx moth (and other native Sphingicampid moths) are very common sights during summers graced by monsoonal moisture. When mature, they reach a size approximating that of a person’s index finger.A few days prior, I encountered this mating pair of diamondback rattlesnakes just outside my shop door. Courtship and mating in this species is a process that can go on for several days.
Another diamondback appeared here last week, a large individual. This snake is quite rotund in the latter half of its body – I’d guess that it was a gravid female. Snakes are a valuable asset here, for they are a major help in controlling rodent populations. Mice and rats in southern Arizona could win gold medals for their ability to get into vehicle engines, where they cause frequent and very expensive problems. Puffballs sprout from the floor of our mesquite bosque with great speed after summer rainfalls. Puffballs are specifically designed to work with rain. First, an initial rain is required to soak the soil. This enables the spherical mushrooms to sprout above the surface. Puffballs quickly mature, then wait for the next rainfall to facilitate their reproduction. When raindrops impact a puffball, they cause a sudden increase in internal pressure, forcing thousands of minuscule spores to erupt (or “puff” like smoke) out of the hole in the top of the mushroom. By releasing its spores only in response to falling rain, the fungus assures that freshly moistened soil is available the enhanced survival and successful growth of its offspring. Pretty cool or what?
July brought us over six inches of very welcome rain! The summer monsoon – one of five distinct seasons here – has returned to southern Arizona after a two-year near-absence. Purple martins are cruising above the treetops and a family of Mississippi kites has been visiting us for days. We are seeing rattlesnakes on a daily basis. On sultry, warm nights, elf owls have been calling in the wee hours of the morning. Saguaros are fattening as they transport water in their tissues. Native grasses are sprouting. The land and its life are rejoicing.
The changes on the landscape are incredible, happening with amazing rapidity and soaring fecundity. The mesquite bosque surrounding our home had been without a green understory during the entire past two years. Not any more! One glance out the window reveals a near-jungle of dense greenery standing five feet tall – much of it composed of one dominant plant with the unflattering common name of “pigweed.”
Fresh growth emerges with stunning speed and vigor after nitrogen-rich summer rains soak the land. This image is a week old; the understory plant community has doubled in height since then.
Pigweed is known to botanists as Amaranthus palmeri, and it is certainly not a “weed.” In the conventional sense, most of us consider weeds to be troublesome non-native plants. This one is a native species, and its presence speaks of great benefits to the land and its wildlife.
One of the primary winter forage plants for the deer that inhabit this river valley is pigweed. A good source of winter forage is critically important to wild ungulates. Rabbits, hares, javelina, and many rodents feed on the green plants in summer. Once the seed heads form, they tend to remain through autumn and winter on dead, standing plants. Great numbers of various species of sparrows winter in southern Arizona. The seeds of pigweed are heavily fed upon by many of these sparrows and other native birds as well. Something that is very obvious, but often overlooked by many people, is the fact that the dense stands of pigweed are shading the ground. I can’t stress enough how important shade is in desert ecosystems! The ground retains much more moisture and soil temperatures are far lower, allowing fungal hyphae and numerous other microflora and microfauna to work in shallower horizons of the soil. This benefits all life.
The summer rains bring many creatures out of hiding. Among these are toads, countless insects, red velvet mites, and the largest millipedes living in the United States…
Giant millipedes spend nearly all of their lives underground, typically emerging only after monsoon rainstorms. This one was about five inches in length; some sources claim this species can reach up to nine inches in length. These fascinating, innocuous arthropods can live for ten years, growing longer as they add more body segments every time they shed.I had taken several shots of the millipede, working close to the ground, before I noticed this small diamondback curled sixteen inches away. It never made a sound. When left undisturbed, these snakes are rarely aggressive. Their primary method of defense is stillness and excellent camouflage.When one of these huge beetles comes flying by, it is guaranteed to get your attention. This is a palo verde root borer, measuring in at three inches in length. These beetles are another example of the many species that are brought out from hiding by the rains.
For many of our of native amphibians, monsoon rains furnish their only chance to reproduce successfully. A strong population of spadefoot toads inhabits this valley, but they remain completely sequestered until strong summer rainstorms bring them up from their deep underground burrows. On July 3rd, the first monsoon storms rolled in – a succession of two storms with plenty of lightning and life-giving rainfall. That night, the landscape was ringing with the voices of hundreds upon hundreds of spadefoot toads.
Couch’s spadefoot toad is the most abundant amphibian in the Middle San Pedro Valley, but only summer residents witness them.A pair of Couch’s spadefoots mating. These amphibians must lay their eggs in water. In desert environments, the toads wait for summer storms to create suitable pools of water. Here, the male is grasping the female in a posture known as amplexus – when she lays her masses of eggs, he releases sperm into the water.
Spadefoot tadpoles mature more quickly than almost any other tadpoles on the planet – in as little as nine days. This is a species that has evolved to live in a hot, dry desert environment, where pools of water are not only rare, but tend to be very short-lived. It pays to mature quickly under such demanding conditions.It is hard to say what to call the amphibians in this brief period of their lives; tadpoles or toadlets? At this stage in their development, the tails shorten very quickly. As newly formed toads appear, they can be seen hopping by the dozens out of their natal pond. Just two days ago, despite the fact that I am always on the lookout for rattlesnakes, I nearly stepped on this one that was well camouflaged under the ramada. I am glad that we did not have an unfortunate interaction.
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.
Early summer in the Middle San Pedro Valley has brought us some uncommon sights. One of our nation’s most dazzling – and sneaky – songbirds is the varied bunting. No larger than a small sparrow, varied buntings often appear black unless they are viewed at just the right angle in favorable light. They occur in small numbers here; we typically see only one or two of them in our bosque every summer. They are sneaky because we never know when they will appear, which is infrequently at best. A beautiful male will drop from the mesquites to grab a quick drink of water from our bird pond, then quickly disappear into the depths of the woodland, not to be seen again for days or even weeks.
My wife Kathleen photographed this male varied bunting through the kitchen window just days ago. When viewed from an elevated position (like our kitchen window), a blazing scarlet patch can be seen adorning the top of the male bunting’s head. This is no accident. Birds often view one another from above, so bright patches of identifying color on the top of their heads help them to keep track of who’s who. Photo by Kathleen Waldt. An even rarer sight here in Cochise County, Arizona comes in the form of another bunting species, the painted bunting. When this female landed at our water dishes in May, Kathleen identified it immediately. The males are among our most brightly colored songbirds, but females are far more subtle. The softly colored green back gives this one away.
Last week, a rare find presented itself in the form of a fresh Gila monster trackway etched into the fine dust along the side of our shop building. The only other animals that can leave similar trackways here are turtles, but a close look at this trackway leaves no doubt as to its maker.
I discovered this trackway less than an hour after it was made, but try as I might, I could not locate the Gila monster that made it. Finding Gila monster tracks is uncommon; finding an entire trackway like this one is downright rare. The animal that made these tracks was a young individual, roughly 9 – 11 inches in length. A closer look reveals distinctive footprints and a drag mark left by the lizard’s tail down the center of the trackway.
The month of May brought the expected blooming of saguaros, but this year the huge cacti did something very strange. Instead of crowning the tips of their trunks and arms with halos of blossoms, they grew flowers both on the tops and down the sides of their heavy arms. I had never seen this phenomenon until this year. Locals are saying that this is a response to the severe drought we are experiencing in the desert southwest. I want to know why the plants are behaving like this.
A very rare sight! Flowers extending far down the sides of saguaro arms. Normally, they are located only at the tips of the arms and atop the crowns of saguaros. Photo by Kathleen Waldt. Another rare sight in the form of a cristate saguaro. Like its neighbors, this one had blossoms sprouting down the sides of its arms.
