A Celebration of Life in the San Pedro Watershed – Native Mammals

Being  grateful for what we have is a wise way to live. With the advent of this new year, I feel an urge to share a gallery of original photographs that reflect that gratitude. It is a privilege to share habitat with the rich variety of living creatures that so grace this landscape. All of the following images, with only one exception, were taken within the watershed of the San Pedro River. All of the animals were wild and free  when photographed. Meet a few of the 90 species of mammals that live here…

This bobcat (Felis rufus) was sitting quietly near a gopher mound, hunting pocket gophers. Eventuallly, the cat’s patience paid off as it nabbed a gopher that made the mistake of peeking out of its burrow at the wrong time.

Trail cameras tend to render very poor quality images, but they do allow us to see things we otherwise might not, like the fire in this bobcat’s eyes. A highly reflective layer of cells known as the tapetum lucidum enables exceptional nocturnal vision for all felines.

The same trailcam recorded this beautifully colored gray fox – (Urocyon cinereoargenteus) a common predator here, but rarely glimpsed because of its nocturnal habits. Gray foxes are among the very few canids on Earth that can climb trees with ease.

A coati (Nasua narica) exploring an old barn. This one was unconcerned with my presence – these are not shy mammals. Coatis are native constituents of the fauna of the Sierra Madrean Ecoregion. Here, they are close to the northern limits of their range.

When mammals grow front claws to lengths like these, it can mean only one thing – that digging is a prominent part of their lives. Coatis use their flexible, sensitive noses to locate underground food sources (mostly insects, grubs, and pupae), then employ their stout claws to dig out dinner.

When they are not raiding gardens or gnawing on the electrical wires in the engine compartments of vehicles, rock squirrels (Otospermophilus variegatus) play a valuable role in the local ecology. Equally at home in the trees or on the ground, this species digs deep burrows to live in. By virtue of their relatively large diameter, rock squirrel burrows furnish secure underground retreats for a wide diversity of other creatures.

This young Mearn’s kangaroo rat (Dipodomys mearni) had become trapped in our (always empty) swimming pool. This species is abundantly distributed in the valley floor, providing food for many predators and playing a valuable role in the ecology of local native plant communities via seed consumption and seed distribution.

Coyotes (Canis latrans) are amazingly adaptable – they are among the few native mammals whose ranges have expanded considerably since the occupation of this continent by Europeans and other non-native peoples. They are also widely misunderstood and unjustly vilified by many people. Is ignorance bliss? Not in the case of the coyote.

I remember how thrilled I was to see my first javelina (Tayassu tajacu) – now I see them daily roaming through our bosque. This one had just finished taking a drink from the San Pedro River.

It would be a misnomer to apply the word “cute” to an adult javelina, but with respect to their tiny young, the adjective fits like a glove. Mother javelinas are both fearless and fierce when it comes to protecting their young, as all good mothers should be.

Desert cottontails (Sylvilagus audubonii) are quite common in this river valley, but they are not often seen due to their preference for staying in or near dense cover. Unlike precocial jack rabbits, cottontails dig burrows and care for their altricial young.

A Botta’s pocket gopher (Thomomys bottae) takes a quick, furtive look at the world of light. This mammal’s life is spent almost entirely in darkness. A keystone species, its role in our local ecology is of pivotal importance. I devoted an essay to this topic in The Life of the San Pedro River.

Here is what gives nightmares to any animals that think they are safe and secure deep in their burrows. Badgers (Taxidea taxus) are enormously powerful rapid digging machines, specialized to follow rodent burrows deep underground until dinner is served. They leave many holes in their wake as they roam large territories seeking food. Badger holes often plunge below the frost line. Their large holes can fit a wide variety of other animals and are used by numerous other species for shelter or brumation / hibernation dens long after the badgers leave them.

I will follow this post with a series of additional blog posts focused on birds, ophidians, and more in celebration of this new year of 2024.

A Landscape in Bloom as Young Ravens Explore Their New World

May is such a beautiful month in the Middle San Pedro Valley! Our mesquite bosque bursts into new life, sprouting a light-filtering canopy of spring-green leaves. Birds are singing from the trees, building nests, and rearing their young. Lizards are a near-constant sight and snakes have been leaving their telltale trackways in the dust. Late in the month, something special happens as catclaw acacias suddenly explode with constellations of pale yellow blossoms, perfuming the valley with their luscious, signature scent. The heat of summer begins to blanket the land in newfound warmth, gearing up toward the frying-pan month of June.

This has been a banner year for catclaw acacia, Acacia gregii. The bushes (at times, these plants grow into small trees) have literally colored parts of the valley floor with an unusually dense show of blossoms. This is one of the desert’s special plants that begs to be appreciated in an olfactory way…push your nose up against any fresh flower, and one whiff of its sweet, heady perfume will weld the current zeitgeist of this wonderful region into your permanent memory.

A dense stand of palo verde (Cercidium spp.) in full bloom colors an entire ridge with literally millions of flowers, all set beneath tall saguaros that are also in bloom. Palo verde and saguaro are two flagship plants of the Sonoran Desert Ecoregion, here reaching its southernmost boundary in the valley along this very ridge. The spot that I stood on to gather this image marks the northernmost extension of the Chihuahuan Desert Ecoregion. Two great ecoregions merge here, enhancing the rich biotic diversity that is so much an intrinsic part of the San Pedro River Drainage.

Most of the early wildflowers are gone by this month, but some wait for their bloom times, like this display of cow pen daisies, Verbesina encelioides.

A closer look at the vivid yellow flowers of cow pen daisies. The yellow “petals” are actually sepals – subtending the many dozens of tiny individual flowers that crowd the centers of these composite blooms.

I am happy to report that our resident Chihuahuan ravens have successfully fledged a trio of youngsters this year. This comes in welcome contrast to last year’s double brood failure; their initial brood was decimated by hungry coyotes on the first night that they spent out of the nest, and the second brood (rare in ravens) was lost to raptors.

Mavis skillfully positions a bulky chicken egg in her beak and readies herself for takeoff. The youngsters must be fed very frequently. Ravens are experts at finding the eggs of other birds. Mike and Mavis never hesitate when we leave an egg on the ground for them.

Loud cries emanating from the raven nest less than 120 feet from my desk window have been a daily part of this month’s panoply of happenings in the natural world. Young ravens have zero shyness when it comes to screaming at their parents for more food, more food, more food! Five days ago, they left the nest to begin exploring the outside world. We see and hear them many times a day as they roam with their parents and learn the complex magic of raven flight mastery. Few North American birds attain a higher level of flight skills than ravens do.

The three youngsters at rest in the mesquite trees only days after fledging. This is a vulnerable and crucial time for the young wolf birds. They must sharpen their flight skills quickly, for predators lurk above and below. It is also the one time in their lives when learning is greatly accelerated as they stay with their parents for weeks, who guard and teach their brood with steadfast devotion.

Raucous cries and characteristic fluttering wings are a part of every feeding, as Mavis approaches one of her ever-hungry youngsters with a crop full of food.

This has been a sad year for migrant birds, with fewer numbers and fewer species than usual, but there are still plenty of feathered creatures bringing life and – at times – utterly dazzling colors to our world. This male broad-billed hummingbird could not possibly have been dubbed with a duller nor less imaginative name.

Among the resident bird species that are still doing well are lesser goldfinches, which crowd our seed bags daily, enriching our surroundings with cheerful choruses of bird song.

During every summer, wet mud or other moist places on the ground attract large congregations of gorgeous, diminutive butterflies. “Blues” as they are collectively called, belong the the lepidopteran subfamily Polyommatinae. Approximately twenty species occur in Arizona. The moniker “blue” comes to light any time these insects open their wings, revealing brilliant blue coloring on their upper wing surfaces. The species pictured is known as the marine blue, Leptotes marina.

Only male “blues” congregate at puddles or on moist soil and animal scats. The males may require certain minerals, amino acids, and/or salts that the females do not. Local native host plants (for their larvae) include saltbush, catclaw acacia and velvet mesquite. Each species has its own hibernation strategy, with some overwintering as either eggs or larvae, as opposed to the far more common lepidopteran chrysalis. Other species  have close associations with ant colonies – such as larvae pupating inside ant colonies, or larvae being tended and protected by ants as they feed on their host plants.

Warm morning light dapples the coat of this mature mule deer doe as she slakes her thirst at our “bird pond.”

A Rare Visit by a Band of Chulos and a Stotting Mule Deer Buck

A reminder: If you are reading this in your email, please click on the blog title to be redirected to my secure blog site, where you will be able to see the header image and enjoy better text and image quality.

First, a note of sincere, heartfelt thanks to everyone who so generously contributed to my appeal for a new pair of binoculars! The appeal was a great success – I am elated to say that the new binoculars are in my hands, and they are absolutely stunning. I cannot adequately express my gratitude for the gift of such an exceptionally important tool that will enable me to continue doing what I do as a naturalist. I’m beaming as I write this.  🙂

White-nosed coatis are one of the most charismatic and fascinating native mammals of SE Arizona. Bands of them are fairly common in the Middle San Pedro Valley where my family and I reside, but I have rarely documented their presence on our property. Only days ago, my wife saw a lone individual close by our home. Two days later, a band of coatis  crossed our little acreage unseen, but they left abundant and unmistakable signs of their presence. 

Just south of the Arizona/Mexico border, coatis are known as chulos (there are several other Mexican names for them); in the US, most people refer to them as coatis or coatimundis. Taxonomically, they are known as Nasua narica. Among a number of their unique features, coatis are one of the world’s very few social omnivores. (Can you think of any others? Offhand, all I can come up with are humans and meerkats.)

Some two decades ago, when I first began to roam the wildlands of this valley, I was not sure how to separate the tracks of coatis from those made by one of their cousins, the raccoon. I had heard that they were difficult to distinguish, but that soon proved to be incorrect. This exemplified one of many things that a naturalist must learn by direct experience out in the field, for the great majority of tracking books fall far short of being accurate, reliable sources of information.

So, how does one recognize the differences between the tracks of these two animals – tracks that, ostensibly, can look a lot alike?

Fresh coati tracks in fine dust under my ramada reveal toes positioned tightly together with consistent thickness along the length of each toe.

These raccoon tracks, particularly those made by the front feet, (at left), show diagnostic shaping and separation of the toes. The toes are proximally narrow in comparison to their distal ends, where they widen into bulbous tips with relatively short claws. Once this distinctive toe shape is recognized, misidentifications between well-defined raccoon and coati tracks can be eliminated.

When a band of coatis forages, they commonly pause in certain areas where they make numerous shallow digs for food such as beetle grubs. The band that visited here just days ago left this characteristic array of holes behind. (Note the 6-inch ruler included in the photograph for scale.) Skunks are common locally, and they also dig for a living, but not in this fashion.

On a hot summer day years ago, I photographed this chulo sign along the banks of the San Pedro River. The coatis had been digging into the sandy riverbank, leaving some spectacularly long claw marks in addition to the excavated holes.

Another pair of native mammals that can leave similar signs of their presence are mule and whitetail deer. One of several ways to distinguish their signs comes into play when these animals are moving at high speeds.  Whitetail deer gallop when they run fast, but mule deer tend to stott when they are in a hurry. Stotting refers to an upward leaping motion where all four feet leave the ground at the same time and land at roughly the same time – a type of movement that most people would describe as a hop. And what a hop it can be!

A mule deer buck moving at high speed left a set of tracks near our home last week, beautifully defined in rain-moistened soil. This deer had easily leapt over two fencelines in less than several dozen yards and had clearly been moving very quickly. I laid a measuring tape on the ground along the deer’s trackway – it revealed a single stott that measured 19 feet, three inches in length. No problem for an adult mule deer.

Here are the four feet of the buck at one of the points where he landed. The deer did not stop here – these tracks were part of a series of energetic stotts. Note that the front feet are positioned ahead of the hind feet, (relative to the direction of travel). If the deer had been a galloping whitetail, this order would be reversed, (rear tracks to the front and front tracks to the rear). Note the spread clouts of the hooves. Deer (and many other mammals, including barefoot humans) autonomically spread their hooves like this in order to prevent slippage as they gallop or stott.

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 Big Buck in His Prime, New Life, and Rescued Wildlife

Winter brings many changes to the activities of our local wildlife. Mule deer move into the mesquite bosques to feed and find shelter. Last year, a magnificent buck lived here, in the company of many does. On a late December afternoon, he stepped out into the light, his neck characteristically swollen in the midst of rut, muscles rippling beneath a sleek coat of winter fur, polished antlers gleaming.

During these stressful times when so many lives are being lost due to the pandemic, it is reassuring and soul-warming to witness death’s opposite: new life coming into the world. A few days ago, I looked out my window to see a herd of javelina, some of them less than 20 feet distant, heading for our bird-feeding area. At this time of year, this group of nearly 20 javelinas visits our place every day and also during the night – seeing them was no surprise, were it not for the newcomers. Several of the adult females had tiny young in tow, varying in age from one or two days to about a week.

Baby javelinas follow closely behind their mothers. Unlike many other native mammals, javelinas do not have a set time of year to give birth, but several females have appeared here recently with newborn young.

When javelina are very young, they often remain nearly hidden beneath their mother’s bellies. They are so tiny that it is easy to miss them as a herd wanders by. I have never pictured adult javelinas as cute or endearing, but a mere glance at one of their stubby-legged babies can quickly reshape one’s views. Those little buggers are, in a word or two, downright cute. They can become otherwise as adults, fouling bird watering dishes, forcing any attempt at gardening in this valley to include stout fencing, and eating much of the bird seed that we scatter for our avian friends. On one occasion, our dog was nearly killed when it charged directly at a full grown javelina. In a split second, the dog was howling in pain as it returned at top speed with a life-threatening gash. Javelina are powerful and deceptively quick. They are well armed with a set of formidable, self-sharpening tusks. The poor little dog simply did not know any better. I did not reach for a rifle after the event occurred. The javelina was simply defending itself; in my mind, it had as much right to be on our land as we do. “Our” land is a place shared with other life. Enough said.

A javelina explores the world with its mother only days after its birth. Female javelinas are protective of their young, as all good mothers are. It is wise to give them room when very young offspring are present.

A year ago, another visitor appeared on a cool winter morning, an animal in serious distress. A hooded skunk had been lured by curiosity to the edge of an empty pool on our property, where it slid down into the bottom, only to find itself suddenly trapped. The vertical walls of that small pool are 5 1/2 feet high. Skunks are not built to be high-jumpers or cliff scalers. Normally, I keep an escape ramp positioned in the pool; a long 2×6 board. I had removed it the day prior when I had cleaned some debris out of the pool, but for whatever reason, I had not replaced it afterward. As soon as I discovered the trapped skunk, I replaced the ramp, sliding it down into the pool gently so as not to put the animal into defense mode. It did not take long for the skunk to walk up the ramp, out of the pool’s clutches.

Empty pools are wildlife traps. A simple escape ramp can make all the difference. Such ramps are also recommended for livestock watering troughs, allowing birds and other small animals a way to get out. A small amount of kindness can go a long way. Here, the hooded skunk ascends its way to freedom.

Once free, the skunk began to amble about, seemingly unruffled by its prior confinement. It was searching for food, and hardly paid me or my wife any mind as it stood less than ten feet from us. I have encountered other hooded skunks in the valley before…every meeting with these creatures had left me feeling that they were utterly inoffensive and little concerned with my presence. Some neighbors reach for a shotgun when  skunks come near their dwellings. Doing so shows a distinct lack of respect for other life and a lack of knowledge when it comes to coexisting with certain wildlife. Much like rattlesnakes, skunks are shy and inoffensive, unless they feel threatened. I know that if I were as small as a snake or a skunk, I would want some potent defensive measures. The rules are simple: maintain distance between oneself and such creatures and leave them alone. Maintaining distance assures one’s self protection. Leaving the animals alone and undisturbed shows respect.

Hooded skunks grow tremendously long tail hairs, a beautiful hallmark of their species.

Skunks bring special distinction to this part of the nation, for their kind are represented by four species here: striped, hooded, hognose, and spotted. Five species of skunks inhabit the United States. Only in a small part of southern Texas, southern New Mexico, and southern Arizonado the ranges of four of the five species overlap.

The skunk was in no hurry to run away after it was free of the pool. It wandered slowly, searching for food, as we stood watching less than ten feet away. This creature was mellow, inoffensive and beautiful; never once did we think we might get sprayed.