For the past three months, hardly a drop of rain has fallen here in the Middle San Pedro Valley. This is, after all, a desert region, or nearly so – deserts are defined as areas that receive less than ten inches of precipitation per year. Here, we get a tad more than that.
A typical rural driveway in the Middle San Pedro Valley; no street lights, no signs, and most of all NO PAVEMENT.
When the skies turned darker and darker shades of gray a few days ago, I was overjoyed. The land – and its life – has been under duress in southeastern Arizona. The past summer “monsoon” season yielded very little rain. So, when it finally began to rain earnestly on, of all days, my birthday, it felt like an exceptionally wonderful gift. As I stepped outside at dawn that morning, the air bore the rich, humid smell of rain and earth and wet leaves. I drew in big lungfuls, savoring the feel, the coolness, the dampness. For most Americans, rain is no big deal, a common part of life. Here, it is always something to be reverently grateful for.
After the rain, the floor of the mesquite bosque (Spanish for the word “forest” or “woodland”) was covered with millions of tiny velvet mesquite leaves.
The ground had changed color in two ways; it had turned darker from the thorough soaking, and had also turned green, carpeted with millions of minuscule velvet mesquite leaves that had been unleashed from the trees by the pelting raindrops. The cyclic path of nutrients from soil to trees and back to the soil lay exposed at my feet, exemplified and accelerated by the rain.
The leaves of velvet mesquite are very small, but they grow in multitudes on the trees, providing a crucially important component of this hot, dry desert ecosystem: shade.
A few hours after dawn, a group of mule deer appeared. They are part of a small herd that has taken up residence in the surrounding mesquite bosque for the past several years. We always welcome their company and never consider them as our “guests,” for they and their kind have been here long before us or our forebears. If anything, we are honored to be guests in their home.
A group of mule deer appeared not long after the rain, foraging on mesquite pods and pigweed (Amaranthus palmeri).
I thought I knew something about rattlesnakes before I moved to Arizona. I had spent decades in Montana, where I had interacted countless times with the single species that lives in that state, Crotalus viridis, known as the prairie rattlesnake. The signs that these snakes left of their presence on the land were usually limited to shed skins, skeletal fragments, or scats. I rarely saw their tracks for the simple reason that the prairies that I roamed in were completely covered with grasses and other plants.
Most snakes leave tracks like this, their serpentine form easily recognized.
Here in southern Arizona, a different situation presents itself, for there are plenty of open areas in the desert where tracks appear readily and often. When I first arrived here, I thought that snake tracks were snake tracks and not much more – until I discovered that rattlesnakes often leave very distinctive trackways. Unlike most other snakes, rattlesnakes crawl in a distinctive manner, known as caterpillar motion. Their bodies remain very straight (rather than sinuously curved) when they travel across the landscape. If a rattlesnake is in a big hurry, it will leave “S”-shaped tracks, curving and sinuous like other snakes. But these vipers are rarely in that much of a hurry, so it is far more common to find their straight trackways, a hallmark of their kind.
Rattlesnakes most often leave very straight, distinctive trackways like this one found on the dusty floor of an Arizona barn.
When rattlesnakes want to stop and rest, they invariably curl themselves into tight, circular shapes. If they have rested on a sandy or dusty substrate, they will leave behind another very distinctive rattlesnake trademark, a circular crater often dug one or more centimeters deep into the ground. No other Arizona snakes that I know of assume this distinctive at-rest posture. Rattlesnakes do the great majority of their hunting in such a stationary, circular posture, where they wait, motionless, for prey to come by. Thus, these snakes are referred to as “ambush predators.”
When at rest, rattlesnakes curl into a tight, circular shape, leaving distinctive craters in the substrate. Here, even the snake’s rattles have left a clear impression in fine, dusty soil. The blue ruler, a standard item in many of my track photographs, measures 6 x 1 inches. For this part of Arizona, a crater of this width represents an average-sized western diamondback rattlesnake about three feet in length.
Why did such behavior evolve in these reptiles? Ambush predators rely on concealment. Most animals, including people, immediately recognize the unmistakable serpentine form of a snake. By assuming a non-serpentine look, rattlesnakes can hide from both their prey and their predators more effectively. I have encountered many diamondbacks and other rattlesnake species, and I can say with conviction that when these creatures are at rest in their usual circular posture, they can be extremely difficult to spot. That is one reason why I usually wear heavy boots and snake gaiters when I am hiking during the warm months. A little prevention can go a long way. Some of the rattlesnake species in southeastern Arizona are exceptionally potent. The average cost of treatment for snakebite is now over $75,000!
This will be the first installment of “Reading Land” on this blog. More will come in the future. The art and science of reading a landscape and its life is at the very heart of what a naturalist does. Learning to read the tracks and other signs that creatures inscribe into the places they inhabit can reveal a great deal of information that may not be gleaned in any other way. “Reading sign” is instinctive with me after a lifetime of study in the outdoors. Read on to discover how animal signs can instill a sense of fascination and wonder in those who learn to notice – and interpret – them.
On a hot, midsummer day not long ago, I walked over to our shed; a simple, no-frills, three-sided building with a dirt floor that all manner of wildlife love to visit. The fine-grained, dry soil renders tracks with plenty of detail. As I walked in, a new set of tracks presented themselves, tracks made by a creature unique to this part of the world, a creature that is very rarely seen in the wild. A Gila monster had investigated the shed, leaving some fascinating tracks. Unlike other lizards in southeastern Arizona, this one has dimpled feet, so identifying its tracks is straightforward as long as the substrate will reveal fine detail. The lizard’s tracks reminded me immediately of porcupines, for they are among the few mammals that also have golf-ball-like dimples on the soles of their feet. I believe the porcupine’s dimples are an adaptation for climbing, and could serve Gila monsters in a similar way. I once thought that these big, bulky lizards were 100% terrestrial, but after living with them for many years, I have learned that it is not uncommon for them to climb up into trees. Bird eggs are highly sought after by Gila monsters; herpetologists state that they have a close association with quail…ground-nesting birds that provide roaming Gila monsters with a rich source of food via their eggs. Why not search the trees for the eggs of other birds?
Strange tracks in my shed revealed the unseen presence of a rare creature, a Gila monster. Note the unique dimples in the tracks.
Finding tracks of a rarely seen animal is exciting! I would have had no idea the lizard was around were it nor for those distinctive tracks. With respect to certain animals, reading their sign has taught me more about them than anything else. Wolverines, for example, roamed the Montana Rockies where I grew up. I have hiked more than 17,000 miles in occupied wolverine habitat in the wildest parts of Montana, but I have only seen a wild wolverine once. They are rare. I learned a lot about them, however, by following their trackways for long distances, particularly during the winter, when snow transformed the landscape into an open newspaper.
A coati in the barn…when lone individuals are encountered, they are usually adult males like this one. Otherwise, coatis are normally seen in social groups.
Here along the San Pedro River, interesting animal signs are often written into the face of the land. One of this region’s other unique animals is the coati. These social omnivores wander the river bottoms in groups of up to thirty or more individuals, foraging for food.
A sand bank along the San Pedro River has stories to tell of the animals that live along the river…
Along a dry reach of the river, I discovered some long claw marks etched into the sand banks, along with some holes that furred paws had been digging into. The width of the claw marks, coupled with the place where I found them, and the animal’s investigation of many of the adjacent holes pointed strongly to the work of a coati. These raccoon relatives dig for a living, using a highly developed sense of smell to locate grubs, insect pupae, and other foods hidden underground. I find their tracks and their signs far more often than I see them.
A closer look at some of the claw marks in the sand bank. These were left by a coati.
It has been quite a while since I crafted a new post for this blog. During the past month, my life had been turned upside down with growing trepidation over the presidential election. I was not in a frame of mind conducive to writing. Now that the election is over, I feel a huge sense of relief and renewed hope. This was an election not only for the people, but one that will benefit wildlife and wild places as well.
I walked a perennial reach of the San Pedro River recently. There was a new beaver dam, just a tiny one that was still under construction. Turkey, javelina, bobcat, deer, coyote, opossum, raccoon, and skunk tracks were visible in the mud along the stream’s edges. I was intrigued to find a set of feline tracks that suggested ocelot or jaguarundi, for they were certainly not made by a bobcat and were just as surely not left by a cougar, even a very young one.
A small, new beaver dam was discovered. This one was constructed using quite a few stones in addition to the usual combination of mud and tree branches.
October has finally brought some relief from the heat that so characterized this summer…109 consecutive, record-setting days of temperatures cresting at 100°F. or higher. The nights have cooled off and crisp air now graces our mornings. Our local woodlands have quieted considerably with the departure of many migratory birds, but there have been some amazing avian happenings here this month. A very rare event happened not long after the sun had set a few weeks ago. My wife, Kathleen, and I stepped outside to listen to the nocturnal sounds coming from the mesquite forest that surrounds our home.
We heard it almost at once, a mysterious, alien-sounding voice emanating from midway up in the trees, only a few dozen yards distant. It was certainly an owl, but not a species that we had ever heard here before. On many a night, we have listened to the calls of great horned, western screech, barn, and elf owls in this woodland, but this was something new, something distinctly different. It suggested a screech owl, but both of us readily agreed that it was not “right.”
I had a growing hunch, so we went back indoors where we consulted a very useful website (xeno-canto.org), one that offers a multitude of audio files for most bird species across the globe. The first species that we chose to listen to was a bird whose range barely extends into the United States, a bird that inhabits oak and conifer habitats high on mountain slopes in extreme southeastern Arizona…
As soon as we heard the recordings, we realized we had a whiskered screech owl hidden in the darkness of the tall mesquites only yards from our home! This was an owl that should not be here, for we live far from the high mountain slopes in the floor of a low-elevation valley. I believe that a major wildfire event from this past summer may provide the answer to this enigma. Less than 20 miles distant, the Bighorn Fire torched nearly all of the mid-to high elevation habitats off the face of an entire mountain range, the Santa Catalinas. Countless birds were driven off of those mountains, subsequently appearing in nearby places where they would ordinarily not be expected. For example, my friend Woody Hume, a very capable naturalist, told me that he had numbers of western bluebirds appearing at his place of residence not long after the fire. That is a species one does not expect to see during summer in the valley floor. Other such unusual species have been reported here this year. I would not be surprised if the owl that galvanized our attention had been living high in the Catalinas and wound up here, temporarily, as it looked for a new place to live.
A fully grown praying mantis crawls across my screen door. This is a gravid female, ready to lay her egg case, as evidenced by her swollen abdomen.
October and November brings new happenings in the insect world of southeastern Arizona. It is common to find adult preying mantises at this time of year. It is impressive to see one of these three-inch, bright green insects in flight. The individual pictured is an introduced species that has become widespread and firmly established in southern Arizona and other parts of our country.
Rarely does one have an opportunity to photograph intimate behavior between wild birds, especially those as wary as ravens. Preening one’s mate is a common occurrence among manny species of birds, but catching it on film is not. Behavior like this underscores the very close bonds that form between highly intelligent birds such as this raven pair, mated for life. My wife, Kathleen, captured this moment between Mike and Mavis, the two Chihuahuan Ravens that have befriended us over the course of many years.
This young bullsnake (a.k.a. gopher snake) was trapped in our dry pool.
Early this morning I walked over to a small, dry pool that is a part of our property to have a look inside. Keeping the pool filled in such a dry part of the world as southeastern Arizona is, to us, an extravagant use of precious water, so it stays dry. The trouble is, such pools are traps for wildlife, hence my daily looks to see what might have fallen in. This morning, a young bullsnake was there. I jumped in, caught the snake, and later released it nearby. The proper local name for this creature is “gopher snake,” (Pituophis cantenifer), but due to my Montana roots, I still use the term “bullsnake” for snakes within the genus Pituophis. They are excellent rodent controllers and a boon to all rural Arizonans. Vehicles and farm equipment are targets for mice, rats, and other rodents that can cause severe damage by chewing electrical wires or constructing flammable nests in engine compartments.
Freedom! The snake just after it was released back into the wild.
My daily inspections of the dry pool have paid off for many animals. Among the rescued species have been other bullsnakes, spadefoot toads, a lowland leopard frog, a Sonoran coral snake, night snakes, glossy snakes, a coachwhip, many lizards, various mice, kangaroo rats, and more. The pool has vertical walls five feet tall, so once such animals fall in, they have no way out. I keep a wooden ramp in the pool, which some animals can use for escape, but many others need help to get out.
An eastern patch-nosed snake asleep in the middle of a roadway…not a safe place for a snake.
Yesterday, as my friend Gilbert Urias and I were driving down a two-track road near the San Pedro River, I put on the brakes to avoid killing a snake that was stretched out in the roadway. It turned out to be a beautiful eastern patch-nosed snake, a small species that is common here in the valley floor. When snakes crawl onto the compacted surface of a roadway, they are often enticed by the heat of such surfaces to stop crawling and bask. Basking snakes often go into a sort of sleep, so they frequently get run over by vehicles as they lay motionless and unaware, soaking up the warmth. I prodded this one gently four times before it came back to life and zoomed to safety, off of the road. Thanks to Gilbert for these nice photographs.
More detailed information on the frequent problems that reptiles must deal with when crossing roads can be found on pages 122 – 124 of my book, The Life of the San Pedro River.
Once awakened, the snake put on a surprising display of speed as it crawled away.
Minutes after I had released this snake, it remained in an alert, defensive position, ready to strike. This diamondback would have died had my friend not discovered it soon after it had become seriously entangled in some plastic mesh. Read the text below to get the full story. Photo courtesy of Gilbert Urias.
What a day and what a week it has been here along the San Pedro River! I just finished freeing a live diamondback from a horrible tangle of plastic bird netting that a friend had put up to keep birds out of his garden. The netting, which resembles a plasticized version of chicken wire, works very well to keep out birds. Its downside is that it also traps snakes. Rattlesnakes are particularly vulnerable to such entrapment because their heads and necks are so much narrower than their midsections…the snakes slip through with their heads, but get caught as they try to squeeze their heavy bodies through. Snakes die slow, lingering deaths when trapped in this fashion. My wife Kathleen held the snake’s neck with tongs as I used a small pair of scissors to cut the tightly wrapped material from its body. True kindness extends beyond our human counterparts to all life, including toxic snakes.
A diamondback rattlesnake lies in wait along the water’s edge at our bird pond. Can you spot it? The snake is located almost dead center in this image.A closer view reveals the snake, motionless, silent, and hungry…
Last week, one of our local rattlesnakes curled up at the edge of our bird pond and proceeded to wait for dinner. Many birds visit the pond daily. This was not the first time I have seen rattlesnakes hunting like this one, waiting at the edge of a water source for a feathered meal. An hour after I spotted the snake, I returned just in time to see a bird’s tail disappearing down its maw. I love watching birds and I welcome the songbirds that come to drink and bathe here, but if a snake decides it wants one for dinner, I will not interfere.
It is common for snakes to yawn after eating. This action helps to re-align and re-seat the serpent’s lower jaws in their proper location.
A few mornings prior, a pipevine swallowtail flew through our ramada to land in a nearby velvet mesquite. Only a scant few species of large butterflies that inhabit our nation are colored blue. This one is my favorite, for they are iridescent, gorgeous insects that have a very specialized relationship with a certain plant that grows here. I wrote an essay about that in my new book, The Life of the San Pedro River, starting on page 155.
The swallowtail sunning itself after alighting in a mesquite. Butterflies do this to raise their operating temperature. Blood in the insect’s wings heats in the sunlight, warming the body as it circulates. Some male pipevine swallowtails have blue coloration on both their forewings and hindwings.
New birds have kept appearing here during the past week as the autumn migration continues. Kathleen spotted – and quickly identified – a female painted bunting that visited us briefly for a single morning. We had never recorded that species here before. Female painted buntings are among our drabbest songbirds, with very few distinctive markings on their bodies…the males, however, are one of our most striking avian species, sporting a combination of bright blue, brilliant red, and iridescent green. Here in southeastern Arizona, painted buntings are at the very fringe of their natural range, thus they are seen quite rarely.
A setting sun steeps the bosque in warm colors. At this time, great horned owls are beginning to exchange vocalizations, and poorwills are calling in the distance. Photo by Kathleen Waldt.
