Category: velvet mesquite

A Celebration of Birds in a Birdwatcher’s Paradise

Few places in the United States can rival the watershed of Arizona’s San Pedro River as one of the nation’s premier birding hotspots. A phenomenal richness of birds has been documented here – well over 450 species. Join  me as I celebrate this gift of life with a sampling of our beautiful, diverse, and fascinating avian fauna…

One of the rarest colors among all the creatures of planet Earth is blue, here brought to brilliant life by a male blue Grosbeak, (Passerina caerulea).

The broad-billed hummingbird, (Cynanthus latirostris), tiny and utterly dazzling, underscores the need for a pair of good binoculars to enable full appreciation – not to mention a heightened sense of wonder – of this jewel-encrusted sprite. Unfortunately, it has been dubbed with one of the dullest and most unimaginative of names.

Hummingbirds are important pollinators of many native plants. Here, a fitting example of coevolution presents itself: the saguaro evolved to raise its flowers high into the desert air as an offering to flying pollinators like bats and hummingbirds. The bats and the birds are able to locate these tall beacons at long distances. The height of the saguaro’s blossoms ensures that its pollinators will remain secure and at ease, out of the reach of a long list of ground-based predators.

Ravens are the most intelligent birds in our country – they possess larger brains relative to their body size than any of our other species. Ravens also have the largest vocabulary of all American birds, they mate for life, and they can live for decades. These black-as-night birds are absolute masters of flight. Magic attends all ravens. This is Mavis, a female Chihuahuan Raven (Corvus cryptoleucus), who has successfully raised many broods here on our property with the help of her mate, Mike.

A fledgling raven spends months with its siblings and parents, exploring and learning about its world. During that crucially important period in their lives, the young birds meet many of their neighbors for the first time. Adult box turtles like this one have little to fear from the fledglings, but neonate turtles are a favorite food.

Cooper’s Hawks, (Accipiter cooperii), are what instill constant wariness and universal fear in most other birds of smaller or equal size. These hawks are specialized, highly skilled bird hunters. Utilizing the combination of a long, rudder-like tail, lightning reflexes, powerful flight musculature, and incredibly sharp eyesight, they are among the world’s most capable avian predators.

The sight of a Crested Caracara, (Caracara plancus) in the Middle San Pedro Valley is a rare treat. Caracaras are classified as members of the Falconidae, the falcon family. The crested caracara is the world’s second largest falcon.

Elegant, gorgeous, and highly social, Gambel’s Quail, (Callipepla gambelii) are common valley residents. The ecology of this species is closely linked with Gila monsters, for quail eggs (and occasionally young chicks) are a major food source for the big lizards.

Greater Roadrunners, (Geococcyx californianus), are a frequent sight here, but seeing them in snow is anything but common, for snow is rare in the valley floor. Their tail feathers display are an eye-catching blend of beautiful iridescent greens and bronze. Roadrunner populations are locally cyclic, but what determines that is something I have yet to learn.

Lark Sparrows, (Chondestes grammacus), are a great example of why no one should be without a pair of binoculars. Seen with the naked eye, they are just another small, drab brown bird. Viewed through binoculars, these sparrows come to life with ornate patterning and rich, saturated colors.

A Loggerhead Shrike, (Lanius ludovicianus) scans for its prey from an elevated perch in a velvet mesquite. “Loggerhead” refers to the shrike’s unusually large head. (The largest non-pelagic turtle in our country also shares this moniker with the shrike: “loggerhead snapping turtle.”) Shrikes sometimes impale their prey on long thorns and even on barbed wire. This beautiful predator has been in sharp decline all across its range for decades. Loggerheads are the only shrike endemic to the United States.

Dressed in vivd red hues, Northern Cardinals, (Cardinalis cardinalis) are a visual standout in any habitat type – that is why cardinals tend to spend much of their time concealed in dense shrubs or other types of thick cover. In the valley, cardinals have a very close association with graythorn (Zizyphus obtusiloba) bushes, where they find safety and peace of mind within the thick maze of very thorny branches that so characterize graythorns.

As humans, we tend to conceptualize and visualize birds either in flight, or as viewed laterally (from the side). I think this posterior view of a northern cardinal may outdo any other viewpoint – what an amazing crest!

Decades ago, Spotted Owls, (Strix occidentalis) ignited a huge controversy when they were added to the endangered species list. Many people lost sight of the fact that it was not just the birds that mattered, for spotted owls were a symbol for what really mattered most: the ecoregion itself – the magnificent coastal rainforests of our westernmost states that have literally been torn to shreds by humanity’s rapacious demand for wood products. Few people know that these owls are also residents of the Sierra Madrean Ecoregion. Sometimes known as “Mexican spotted owls,” this subspecies – Strix occidentalis lucida – reaches the northern tip of its range in the San Pedro Watershed. During a very lucky day, I photographed this individual in the Huachuca Mountains.

There are few more vivid ways to mark the coming of spring to the Middle San Pedro Valley than the arrival of Vermillion Flycatchers, (Pyrocephalus rubinus). These tiny birds light up the fields and bosques in early March – before the mesquite trees leaf out. Adult males are wearing freshly grown feathers in March, plumage so pure and bright that these minuscule flycatchers can be seen with the naked eye at distances approaching 100 yards. Their crowns sport the most radiant part of their plumage, hence the name “Pyrocephalus,” which translates to “flaming head.”

Rare Autumn Color Transforms the San Pedro’s Forest

For the past three years in a row, I had made a date with the San Pedro River: I would spend my birthday walking the river under the gilded magnificence of tall willows and stately cottonwoods alight with prime autumn color. For the past three years, the autumn colors have failed to shine. “Autumn,” if you can call it that, comes late to this river’s riparian forest. Fall colors do not peak here until the second week of December. The timing does not vary due to temperature or climate, it functions via the most universal and reliable of nature’s temperate region chronometers: the photoperiod. In most years, the trees along the river either suffer a hard freeze before the second week of December, or they get stripped off by strong winds, or both. Freezes can rob the forest of its fall color overnight by turning all of the leaves a withered brown. 

When conditions are just right, chlorophyll fades from the leaves to reveal anthocyanic compounds that transform the forest canopy into a fluttering galaxy of bright yellow leaves. This year brought a reprieve from late November winds and early December freezes – this was one of those special years…so I set out for a walk on my birthday, a serene journey into the river forest. The following images help to tell the story of a rare day on the river.

The  first place I walked to that morning was a hilltop where I saw the lone cottonwoods pictured above, lifting plumes of sunlit gold skyward. As I watched, a great egret came sailing out from behind the trees! Imagine an elegant pair of outstretched wings spanning over four feet, the bird flawless, brilliant snow-white, set against a clear blue sky. My wonderful new binoculars brought this seldom seen creature in close and sharp – what a gift it was to witness the egret! My jaw went slack when a second egret appeared to join the first. The pair then departed northward, winging over the tops of the trees as they followed the river that sheltered and fed them. I envied their freedoms.

A rich blend of plant communities (and thus many habitat types) is underscored by the blaze of autumn color along the river. Here, a dense growth of velvet mesquite and catclaw acacia flank the riparian forest. Highlands are visible in the distance, providing more habitats for wildlife and wild plants that vary according to aspect and elevation.

I left the hilltop, then returned to the riparian forest, where I walked down to a favorite sitting spot by a bend in the stream just below a vertical cutbank. There, a set of cougar tracks was pressed into  the moist sand, made the night prior by an adult male. I sat under a willow to look, to watch, and to take in the morning’s biophony. The forest was quiet, the still air punctuated by a slight rustling of leaves above, the quiet murmur of the river water, and the voices of a few birds. As sunlight warmed the cool air, small clouds of midges began to rise within discreet, sunlit areas above the water. There, the air temperature was most favorable for their airborne gatherings. As the midges danced in the light, a gray flycatcher began sallying back and forth into the insect clouds, garnering breakfast with typically adroit flycatcher movements. Then another bird joined in the feast, flying into the swirling insects to garb morsel after morsel with some amazing acrobatics. It turned out to be a ruby-crowned kinglet! I had no that clue kinglets could – or would – engage in such feeding behavior.

A favorite and long-familiar reach of the San Pedro River in mid-December dress.

Next, I walked down the river until I got near the northern terminus of my trail. The going was easy, the stream shallow in most reaches. I was glad to find no recent signs of trespass cattle anywhere, nor any signs of feral pigs. There was little in the way of animal tracks, as a heavy mantle of recently shed leaves covered most of the ground thoroughly.

A dense carpet of crisp, shed leaves draped the forest floor. This made for noisy walking!

I heard these Gould’s turkeys before I saw them emerge from the forest to slake their thirst at river’s edge.

Gooding’s willows cast long shadows into a beguiling artist’s chiaroscuro of glistening water, dappled light, and autumn leaves.

As I neared the end of my walk, I veered into the forest to avoid some deep water. (For much of the way, I’d been wading.) The wind suddenly arrived, causing a blizzard of shimmering golden leaves to return to the ground that had bore them, an entrancing display of fluttering motion and light as one of nature’s grand cyclic acts of life unfolded all around me.

Truly a stellar birthday!

RAIN GRACES A DESPERATE LANDSCAPE AND A RARE VISIT BY A GILA MONSTER

I am happy to report that the Middle San Pedro Valley has finally received some summer rain! This has been a very dry summer – during July and August, we have received only .63 inches of rain. Most of that has occurred during the past four days. The summer “monsoon” season is what literally defines this ecosystem – enabling much of the rich assemblage of plant and animal species that makes this part of Arizona such a remarkable place.

Despite the extended drought, the velvet mesquite trees in the local bosque have put on a tremendous spurt of foliar growth this year. Additionally, the trees have flowered three times since spring. As I write this, the ground under the trees is plastered with a heavy crop of “beans,” the nutrition-packed seed pods that are one of the cornerstone food sources for our wildlife. How can this happen during such a bone-dry, hot spring and summer? The answer is rooted in last year’s very wet monsoon season. Mesquites have a remarkable ability to move rainwater down their roots, where they store it at depth for later use. That’s right; these trees can move water in both directions in their root systems! The big bean crop owes its genesis to last year’s stored rain water.

Wind plays a pivotal role in the ecology of velvet mesquite trees. When the seed pods are ripe, winds accompanying rain storms can release astounding quantities of pods in very short periods of time. Pods on the ground then become available to all wildlife, not just the species that climb trees. Mesquites depend upon animals to remove the tough outer seed coating by chewing and gnawing on the pods. The seeds of mesquite trees are able to germinate only after the outer husk is removed.

This beautiful bumblebee appeared last week, an uncommon insect in local bosques. The ecology of bumblebees is intimately woven around the activities of small rodents. Local bumblebees make their colonial nests in the abandoned underground nests of mice and kangaroo rats.

Iridescent scales glitter on the back of this Clark’s spiny lizard, at rest in the shade of my ramada on a 108°F. day. Prime habitat for this species are mesquite bosques, where the trees offer an abundance of shade and escape routes from predators. Clark’s spiny lizards can climb trees with the speed and agility of an over-caffeinated squirrel.

Within the sheltered confines of a small depression in the joined trunks of two mesquites is a small rodent’s dining room – in this case, likely an Ord’s kangaroo rat. Note the many chewed fragments of mesquite pods. Kangaroo rats and many species of mice prefer such places to gnaw on their foods.

As of this writing, the raven family is still together as the trio of young birds explore their new world, constantly learning from their devoted parents. That’s papa Mike in the foreground, Mavis in the background, and their rowdy, inquisitive kids in between.

Mavis eyes up one of her favorite foods. Large eggs like this one must be held in the bird’s beak with skill and finesse. She sauntered off with this one, walking some 90 feet into the bsoque, then gently dropped the egg, dug a hole, placed the egg into the hole, then covered it with soil and duff. The spatial cognition and spatial memory of ravens is astounding. Hundreds of food items get stashed in tree crotches or buried for later use – with uncanny ability, the ravens remember where every one of them is hidden.

This morning brought us a seldom-seen spectacular visitor in the form of this Gila monster that was crawling along the foundation of our home.

When viewed dorsally, the reticulated patterns on the backs of Gila monsters really stand out – patterns that are mirrored in the art of many native southwestern cultures and tribes. No two Gila monsters are patterned alike, so photographs can identify specific individuals. This one is an adult, about 14 1/2 inches in length.

An Inferno of a Summer, Huge Arthropods, and Arizona’s Tiniest Mammals

This has been one of the driest and hottest summers I can recall here in the Middle San Pedro River Valley. During “normal” summers, monsoon rains arrive between the middle and the end of June and continue through August and much of September. The two previous monsoon seasons brought us a welcome abundance of rain, but this year has remained very, very dry. Daytime highs for the past six weeks have averaged around 106°F., with more than a few days reaching 110° or higher. This year’s highest temperature registered at a crispy 115°F. on July 17.

Our mesquite bosque remains dry, the understory of dense London rocket plants yellowed and brittle. Usually, by the end of July, this scene should be bursting with vivid green growth in the form of Amaranthus palmeri and many other native plant species.

Despite our xeric summer, velvet mesquite trees in our bosque have produced a nice crop of pods, followed by a second flowering during the past couple of weeks. The trees are drawing on water from last summer’s abundant storms; mesquite has the rare ability to transport water in both directions within its extensive, very deep root system. Water can be transported deep underground and stored for later use.
A fresh splay of velvet mesquite blossoms perfumes the air and reminds us that desert plants have evolved uncanny mechanisms to stay alive and even thrive under dry, difficult conditions.

Mesquite blossoms lead to garlands of bright green pods growing from pendant branches. Mule and whitetailed deer love to feed on low-hanging bunches of these young pods. When ripe, the seed pods turn yellow and fall to the ground. There, they become one of the most crucial and nutritious wildlife foods in the entire ecosystem, eagerly fed upon by a very long list of native animals from mice to coyotes to bears and many more.

Despite the drought, this was a banner year for a widespread local species known as catclaw acacia, Acacia gregii. (See the photos in my previous blog post.) Throughout the valley, these large shrubs/small trees flowered explosively. The scent from their blossoms is intoxicatingly wonderful. Much like mesquite pods, the seed pods of acacias are fed upon by a wide variety of native wildlife.

Dry conditions leave fine coatings of dust on our driveway – an excellent newspaper that I strive to read daily. This summer has revealed tracks of mice, kangaroo rats, gray foxes, coyotes, raccoons, mule and whitetailed deer, a cougar, hooded skunks, quail, doves, and other birds including this trackway of a Chihuahuan raven.

A closer look at the raven’s tracks reveals their relatively large size, distinctively lobed feet, and shallow drag marks made by their posterior claws.

A mystery…last week, I noticed something I had not seen before: dense clumps of small, black native bees forming in certain graythorn (Zizyphus) bushes. I have no idea what is going on here, nor what species these bees are – there are well over 1,200 species of native bees in this ecosystem, representing the richest known bee fauna in the world.
I found this adult giant mesquite bug (Thasus californicus) roaming under my ramada the day before I posted this blog. These are large insects that are true bugs (Hemipterans) as opposed to a type of beetle (Coleopterans).

A lateral view of the mesquite bug reveals the tube-like mouthpart that it uses to feed on plant liquids. The tube is inserted, syringe-like, into the stems of plants. These specialized feeding tubes are a primary characteristic that separates true bugs from beetles.

Prior to maturation, giant mesquite bugs exist in the form of wingless nymphs. The nymphs form colonies that feed on liquids from various species of trees and shrubs. The nymphs go through several instars before finally transforming into adults, all of which exhibit these very bright red colors. The nymphs are protected with self-manufactured noxious chemicals that make them taste bad to predators, hence their aposematic coloration.

Arizona’s smallest mammals are shrews; I found this one – dead but still warm – on the floor of our bosque. This species is known as the desert shrew, Notiosorex crawfordi. Shrews are among the most highly energized, frenetic mammals on Earth. They require remarkable amounts of food – up to nearly half their body weight on a daily basis. They almost never stop moving, constantly on the hunt. I wonder how they have time to dream.

This sight greeted me a few mornings ago, when I walked outside just after dawn to see this giant centipede (Scolopendra heros) clinging to the wall of my adobe building. The broom handle gives a sense of scale. This one was just under seven inches long – and they get bigger than this, up to nine inches in length. Very large specimens measure around an inch in width across their backs, are equipped with formidable pincers, and can move at astounding speeds.

High winds snapped this velvet mesquite trunk at the location of a cavity hollowed out by Gila woodpeckers. I have seen such tree breaks many times, both locally in this southern desert and in the northern Rockies. There is a complex relationship between cavity-making birds and their varied roles in forest ecology that may be more important we know.

A close look at the exposed woodpecker cavity shows the remnants of a successful nesting season. Last month, a pair of ash-throated flycatchers raised a batch of young within the sheltered confines of this tree cavity.

This image should be entitled “HOPE”… a series of empty, dry water buckets under my roofline, hoping and waiting for the summer rains. Why collect rainwater when we have a well, particularly summer rain water? The summer storms often feature stunning amounts of lightning, which allows substantial amounts of elemental nitrogen to be carried from the atmosphere (via rainfall) down to the ground, where it greens the Earth. All gardeners should learn that summer rain water collected after lightning storms works magic on plant growth.

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.”

An Astonishing Eruption of Beetles, a Rare Visitor, and Bosque Lushness

There has been a sudden and tremendous eruption of small beetles in the local mesquite bosque. A dense, tall understory of pigweed, (Amaranthus palmeri) covers the floor of the woodland, an exuberant growth enabled by recent monsoon rainfall. When I walked into these plants this morning, curtains of tiny beetles took flight  from the pigweed at my every step, thousands upon thousands rising upward like a reverse blizzard.  

The leaves of the pigweed plants had become dotted with countless small holes during the last two days. This morning, the plants revealed that an orgy of feeding had taken place during the night. Literally all of their leaves had been reduced to a ghostly remnant of reticulated veins with no leaf tissue left in between. Every plant, everywhere I looked – consumed overnight.

Acres and acres of bosque understory were fed upon by an almost inconceivable number of small insects. The plants looked almost shredded.

A pigweed leaf after the night’s heavy feeding spree.

Naturally, I had to know what these beetles were. They were diminutive, measuring around 4-5mm in length. Up close, the beetles were beautiful, sporting brightly colored, broad white bands running lengthwise across their shiny black elytra. After some research, I learned that they were known as “pigweed flea beetles,” Disonycha glabrata. Their ecology entails a close relationship with specific host plants – they will feed only on plants in the genus Amaranth. I have witnessed dense growths of pigweed during most of my summers here; I had noticed these beetles in prior years, but never in such spectacular abundance. Why had their population so suddenly rocketed this year? I can only guess. Perhaps this year’s rains were perfectly timed at just the right intervals and in perfect amounts to encourage such an event? Maybe it has something to do with their predators…or  some other mechanism?

A pigweed flea beetle, Disonycha glabrata.

When insects erupt in large numbers, people are often quick to react with alarm and negative attitudes. Yes, they shredded an entire forest understory – but was that a bad thing? Or simply natural change? It is not our place to pass judgement on what happens in the natural world. Both the beetles and their host plants are native constituents of this ecosystem. So, I do not necessarily think that what has happened is somehow wrong or alarming, but it is interesting.

I found another creature wandering in the pigweed last week – a young adult Sonoran Desert Tortoise! We see these reptiles rarely here in the bosque; they are more partial to nearby upland desert habitat types. This one’s carapace was between 9 – 10 inches long, and like most of its kind, it was cautious, slow-moving, and appeared unfazed by my presence.

The Sonoran Desert Tortoise that I discovered resting peacefully under the trees. This reptile and its close relatives have recently undergone taxonomic revision – to scientists, it is currently known as Gopherus morafkai.

The tortoise’s powerful front legs are clad in rows of thick, hard scales that assist in digging and may help the turtle resist serious injury from predators. When threatened, the tortoise tucks its head in and then covers its front with these remarkably well-armored legs.

A few days ago, I went out on a walk with a naturalist-friend. He shared a special area with me, a mature mesquite bosque with a remarkably rich, lush understory. I was deeply touched by the feel and presence of this almost subtropical woodland. The image below provides some insight into the kind of verdant growth that this “desert” valley is capable of hosting.

A jungle-like wall of vining plants drapes over young trees and shrubs in one of the most lush, beautiful velvet mesquite bosques I have ever seen. Just beyond the reach of this image was a barbed-wire fenceline. On the far side of the fence, cattle grazed – the ground under that part of the forest had been virtually wiped clean, transformed into a deeply impoverished world with respect to native plants and wildlife. Mesquite bosques as rich and fecund as this one have become very rare – cattle are commonplace. How is this right?

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.

An Incredible Camouflage Act, Autumn Discoveries, and a Tree-climbing Milkweed

For many living things, effective camouflage often means the difference between life and death. I have witnessed camouflage acts that left me amazed – snowshoe hares in winter, whose fur matched the color and reflectivity of snow perfectly, or the disappearing act of a snipe crouched in grass…but lately, I witnessed a larval insect whose camouflage made my jaw drop.

One of the strangest caterpillars I had ever seen…

The creature had brashly exposed itself by falling from its perch in a velvet mesquite tree to land on a hand railing that had been painted white. It had gone from near invisibility to “How could you possibly not see me?” in the blink of an eye. Clinging to the railing was a slow-moving, two-inch caterpillar cryptically colored with dull greenish-gray skin. Hair-like filaments extended from its prolegs to form a peripheral fringe around the  caterpillar’s body. The filaments served to effectively break up its outline. As if that were not sufficient, the crypsis of this larval moth went a step further, for the caterpillar’s body was quite flattened. In cross section, most caterpillars are round or somewhat ovoid, but this one had a cross-sectional shape more like a thin, gently curved crescent. This unusual shape meant that the dull-green, fringed caterpillar could literally melt into a twig or a branch to cloak itself in obscurity like a ghost in a fog bank.

Later, some research revealed that the creature in question was a lappet moth caterpillar, possibly of the genus Gastropacha. The word “lappet” is used to describe a fold or flap in a  garment or headdress. Thus, lappet moths (family: Lasiocampidae) get their name from the hair-like fringes that project from their larvaes’ prolegs.

A lappet moth caterpillar that had fallen out of its element – transformed from profound obscurity to blatant visibility.

During the autumn of 2021, discoveries here in the surrounding mesquite bosque included this banded gecko that had dropped into an old bucket. These velvet-skinned reptiles are common here, but remain well hidden and inactive during daylight hours. Geckos are among the few truly nocturnal constituents of Arizona’s rich saurian fauna.

I found this young glossy snake hidden beneath an old piece of plywood on the ground. Glossy snakes are often mistaken for gopher snakes. These beautiful, innocuous reptiles can reach lengths of nearly five feet. They are among this area’s most common serpents. Their scientific name is a gem: Arizona elegans.


The 2021 monsoon brought a cavalcade of change to the Middle San Pedro Valley. Late in autumn, large numbers of Empress Leilia butterflies (Asterocampa leilia) could be seen adorning the landscape. Abundant rainfall spurring rapid growth of their food plants likely played a major role in the eruption of these insects. Their caterpillars feed on desert hackberry, Celtis ehrenbergia (formerly pallida).

Take a walk in a local bosque late in late autumn and you are likely to see what look like little clumps of snow in the distance, gleaming white patches that really stand out on the dark-colored floor of the woodland. A closer look reveals a surprise; a mass of seeds from an unusual member of the dogbane family known as climbing milkweed, Funastrum (formerly Sarcostemma) cynanchoides. Unlike most other types of milkweed plants, climbing milkweed is a true vine, ascending to heights of 10-12 feet in tall shrubs and trees.

It is hard to miss the contrast between a clump of climbing milkweed seeds and the floor of the bosque.

After pollination, the flowers of climbing milkweed form pods that eventually fall to the forest floor, where desiccation causes them to split open and unfurl a beautiful array of seeds embedded in a mass of gleaming, silvery-white filaments.

A closer view reveals numerous seeds, the future of the species encapsulated within each one. Climbing milkweed is a host plant for the larvae of both queen and monarch butterflies.

Individual seeds can be carried long distances by wind currents, effectively distributing the plant’s progeny across the landscape. Wide distribution of seeds enhances the probability for successful germination and the continued success of the species.

A Photographic Tour of Early Summer Life Along the San Pedro River

First, an important message to my readers: For a much better experience, when you receive notice of new blog posts in your email, please be sure to click on the blog’s title. That will take you to my blog website, where the photographs are larger and the text is more readable. Also, there is a “featured image” at the top of every new blog post that does not appear in the email version. Do this now – you will notice a substantial improvement!

Summer has come to the river and its valleys, bringing a cavalcade of change to the animal world. Today, my thermometer registered 113° F. I don’t leave southern Arizona during the summer like so many people do every year. This is my favorite season here, because so much happens in the natural world during the fierce heat of summer…

Mike and Mavis have successfully raised their seventh brood here on our land. This year, four new ravens have fledged and left the nest. Here are two of them. Note the pinkish-white bordering around their beaks and their pink mouths. As they mature, the pinkish color on their beaks disappears, and the inside of their mouths turns black.

Several weeks ago, the velvet mesquite trees erupted with fresh blossoms. These are the precursors to an abundance of bean pods that provide one of the most crucially important food sources for the valley’s wildlife.

A closer look at the flowers of a velvet mesquite tree. These blossoms perfume the air with a sweet, heady fragrance.

A queen butterfly alights to drink from the wet mud surrounding our watering hole. This insect is often mistaken for its well-known cousin, the monarch.

The back side of a male Gould’s turkey in full display. These birds – and their tails – are huge! The white tips on the tail feathers are one of the field marks that distinguish this race of wild turkeys from their eastern relatives. Part of the display involves dragging the wing tips on the ground, an action that creates a loud rasping sound, meant to intimidate rival males.

A male summer tanager comes to feed from a block of suet. This is America’s only all-red bird, a living statement of resplendent color and grace. Their future in this valley is being threatened by large numbers of brown-headed cowbirds.

This male black-headed grosbeak has been sending his voice through the bosque every morning, a series of loud, robin-like notes.

Few of our western birds are more strikingly colored than the western tanager. A different race of this species stays here in the valley floor to breed every summer. Most western tanagers utilize very different breeding habitats – namely, conifer forests at higher elevations.

A male blue grosbeak that visits daily for water. Blue is one of the rarest of colors among Earth’s terrestrial vertebrate animals.

A new beaver dam graces the flow of the San Pedro River. Dams like this permit substantially more water to infiltrate the ground below their surfaces, recharging the shallow aquifers that give life to the river’s riparian forests of cottonwoods and willow trees. There were five more dams below this one. I cannot think of a single mammalian species that is more beneficial to the river and its forests than beavers are.

I awoke one morning to find this characteristic fresh imprint at the foot of my entry steps. A rattlesnake had curled up there the night prior, leaving its signature circular mark. No other Arizona snakes rest in such a circular position. For reference, the grizzly track cast in concrete is six inches in width. Grizzlies were once common along this river until they were wiped out by Spanish and American settlers.

A black-tailed jackrabbit resting in the shade of a mesquite trunk on a toasty summer day. When the heat cranks up, animal behavior changes. This hare let me approach within four feet, something it would not have allowed on a cooler day. The name “jackrabbit” is a misnomer, as these creatures are hares, not rabbits.


Until I came to live in southeastern Arizona, I would not have believed that there could be pink snakes native to our country. This coachwhip snake appeared on a hot afternoon, five feet of blazing bubblegum pinkness!

Coachwhip snakes are expert climbers. Kathleen and I looked out a window one day to see this tail protruding from an active Gila woodpecker nest. Fortunately, the snake did not wipe out the entire brood – it consumed one or two nestlings and moved on.

A gopher snake encountered on a sandy bank of the San Pedro River. These snakes attain lengths of seven feet or more and are often mistaken for rattlesnakes. They are among the most effective rodent controllers we have. Favored food items include mice, rats, and gophers.

A diamondback rattlesnake slithers through the mesquite bosque, traveling in a manner common among rattlesnakes, using caterpillar motion. When snakes crawl in this fashion, their bodies remain almost straight rather than sinuously curved. We never kill these animals. They have a right to live here, no less than we do. When summer comes, we are always on guard, watching closely where we place every footstep, especially after dark.

Beavers add a special touch of beauty to the river, creating ponds that mirror their surroundings and provide needed habitat for a long list of other creatures.

A RAVEN’S UNFORGETTABLE COURTSHIP DISPLAY, RARELY SEEN!

“One thousand feet above the valley floor, a large bird cuts an arc across a universe of clear azure sky. The bird is black, so black that it pierces a hole in the heavens, a mysterious place where all light gathers to coalesce into an extraordinary being. It is a creature wrapped in a cloak that dines on light, a creature that melts into the darkness of midnight but lives to greet the morning sun. It is an exquisite merging of feather and form, a fusion of mind and voice that we know as the raven.”

That is how I opened the essay on ravens in my new book, The Life of the San Pedro River. I have nurtured an ever-growing fascination and respect for ravens since my teenage years. Here in southeastern Arizona, my wife and I share land with a pair of Chihuahuan ravens that we have known quite closely for the past nine years. They are Mike and Mavis. Their lives have been undergoing an exciting change during the past month.

Mike maintains a daily presence here, forever welcome. His mate is almost always close by.

For six consecutive years, Mike and Mavis raised annual broods of young ravens in a nest located in a mesquite tree only 110 feet from our home. However, during the past two years, they moved to a new nesting site on a neighbor’s property some 300 yards distant, again in a tall mesquite. We missed them!

Mike digging with his beak. Chihuahuan ravens commonly cache food items for later use. Some food is placed in the crotches of trees. Far more often, these birds dig holes, drop a morsel of food into the hole, then cover the food with an inch or two of soil. Equipped with exceptional minds, ravens have no trouble relocating their numerous, well-hidden caches, even weeks later.

Despite the fact that ravens have stout, formidable claws, I have never seen them use their feet for digging, as other birds do.

Four weeks ago, I looked out my office window to see Mike fly by with a stick in his mouth. He was not heading south towards the distant nest site, but instead flew about 100 feet to the north and lit in a mesquite, where he placed the stick. That got my attention! As I watched during the days that followed, it became clear that a new nest was being built on our property.

The pair bonding between adult ravens may be closer and longer lasting than any other North American birds. Mike and Mavis are together year-round; feeding, foraging, nesting, exploring, and sleeping as a pair. That’s Mike on the left; note his thicker neck, larger head, and bigger body in comparison to his female companion.

Watching ravens build a nest is a lesson in patience, determination, and tenacity. Branch after branch is carefully selected, then carried aloft to the tree. By “carefully selected,” I mean just that – if a stick is partially rotted or otherwise infirm, it won’t do. Each stick must be within certain parameters with respect to weight, thickness and length. Once a suitable stick is found, it is skillfully balanced in the beak for the flight to the nest, then placed in a manner that is anything but random. For three weeks, I watched as hundreds upon hundreds of sticks left the forest floor to become airborne, a reverse journey back into the canopy they had sprung from. A nest took shape, growing deeper day by day. Three weeks passed, then Mike and Mavis abruptly changed their behavior. Stick gathering  had been completed, so it became time to line the nest with soft, fluffy materials. Scouring the neighborhood, the ravens found lengths of discarded baling twine, clumps of horse and deer hair, even pieces of cardboard that they ripped from a box that had been stored in an open shed. Now fully complete, the nest awaits its purpose. Soon, Mavis will lay her eggs and a new generation of some of the most intelligent birds on Earth will come into being.

The newly constructed Raven Hilton, built in the branches of a velvet mesquite. If all goes well, we will soon hear new voices emanating from the nest. Hatchling ravens produce low-volume, unique sounds that rapidly increase in volume and complexity as they grow.

One morning during the nest-lining period, both ravens came gliding through the trees to land on the ground within a dozen feet of my wife and I as we were seated under the ramada. Some very delicate, amorous preening followed as Mike ran his beak through Mavis’s neck and chest feathers. The birds were conversing with one another as this took place, uttering a soft language known only to them, a language marked by the deep-seated intimacy of a life-long pair bond that can last more than a quarter century. The preening done, Mike ambled over to within a dozen feet of us. There, he began a courtship display, hoping to win his mate’s admiration and acceptance. He lowered his stance until his body was almost flat on the ground, then fanned his tail wide. He partially opened his wings and erected the feathers on the crown of his head. His sleek indigo-black body quivered as he made a series of soft, percussive snaps with his stout beak. We were very lucky to witness this, and even luckier to get a few photographs. Only a few scant minutes of each year are dedicated to such interludes in the lives of ravens, interludes that maintain the circle of life.

Mike performing his courtship display.

As I was just about to hit the “publish” button to launch this blog post, a sudden drama unfolded just outside my office window. A red-tailed hawk made the mistake of flying too close to the new raven nest. Mike took off at high speed, chasing and diving on the hawk relentlessly. Ravens are masters of flight, a fact quickly apparent to anyone who has watched such events unfold. With very quick, elegant turns, dives, and rolls he chased the raptor for more than 250 yards before finally returning to the nest site. I have watched this pair of ravens defend their nesting sites with great vigor and determination many times. They have given brave and vociferous chase to coyotes, bobcats, a gray fox, many hawks, and more over the years. Anyone reading this who has raised children should understand such actions. I was once charged – repeatedly – by a ruffed grouse defending its chicks. Mind you, that is a bird no larger than your average chicken. I know of a Montana grizzly bear that charged and bit a slow-moving locomotive three times after the train hit one of her cubs. Motherhood and the protection of one’s young are among nature’s most powerful and important forces.

For much more on these incredible, amazing birds, read the essay entitled “Mike and Mavis” in The Life of the San Pedro River. 

For an even deeper journey into the fascinating lives of ravens, I highly recommend these two books, written by Dr. Bernd Heinrich, an astute biologist and acclaimed author: Ravens in Winter, and Mind of the Raven.