Early summer in the Middle San Pedro Valley has brought us some uncommon sights. One of our nation’s most dazzling – and sneaky – songbirds is the varied bunting. No larger than a small sparrow, varied buntings often appear black unless they are viewed at just the right angle in favorable light. They occur in small numbers here; we typically see only one or two of them in our bosque every summer. They are sneaky because we never know when they will appear, which is infrequently at best. A beautiful male will drop from the mesquites to grab a quick drink of water from our bird pond, then quickly disappear into the depths of the woodland, not to be seen again for days or even weeks.
My wife Kathleen photographed this male varied bunting through the kitchen window just days ago. When viewed from an elevated position (like our kitchen window), a blazing scarlet patch can be seen adorning the top of the male bunting’s head. This is no accident. Birds often view one another from above, so bright patches of identifying color on the top of their heads help them to keep track of who’s who. Photo by Kathleen Waldt. An even rarer sight here in Cochise County, Arizona comes in the form of another bunting species, the painted bunting. When this female landed at our water dishes in May, Kathleen identified it immediately. The males are among our most brightly colored songbirds, but females are far more subtle. The softly colored green back gives this one away.
Last week, a rare find presented itself in the form of a fresh Gila monster trackway etched into the fine dust along the side of our shop building. The only other animals that can leave similar trackways here are turtles, but a close look at this trackway leaves no doubt as to its maker.
I discovered this trackway less than an hour after it was made, but try as I might, I could not locate the Gila monster that made it. Finding Gila monster tracks is uncommon; finding an entire trackway like this one is downright rare. The animal that made these tracks was a young individual, roughly 9 – 11 inches in length. A closer look reveals distinctive footprints and a drag mark left by the lizard’s tail down the center of the trackway.
The month of May brought the expected blooming of saguaros, but this year the huge cacti did something very strange. Instead of crowning the tips of their trunks and arms with halos of blossoms, they grew flowers both on the tops and down the sides of their heavy arms. I had never seen this phenomenon until this year. Locals are saying that this is a response to the severe drought we are experiencing in the desert southwest. I want to know why the plants are behaving like this.
A very rare sight! Flowers extending far down the sides of saguaro arms. Normally, they are located only at the tips of the arms and atop the crowns of saguaros. Photo by Kathleen Waldt. Another rare sight in the form of a cristate saguaro. Like its neighbors, this one had blossoms sprouting down the sides of its arms.
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.
This was one of those things that had to be seen to be believed. Recently, a friend sent me an email with some attached photographs of Chihuahuan ravens that he had taken in early May here in the valley. He kindly gave me permission to post his images on this blog.
There are some things that go beyond the “once-in-a-lifetime” category. Seeing a Chihuahuan raven with brown wings and tail surely must qualify.
In another instance, my friend was able to photograph a dispute between two ravens. The images appear to indicate a serious altercation. Such events are witnessed very rarely; even more rarely are they captured on a camera. I do not know what caused the aggression. It is nesting season for our local ravens. Perhaps one of the birds had tried to raid the nest of the other one, or was this a male vs. male squabble over a female? Only they know.
Two male ravens engaged in an uncommonly serious dispute. In all my years of watching ravens, I have never seen anything quite like this.Note the thick, heavy necks and heads on these adult Chihuahuan ravens. One way to tell the sexes apart is via such characteristics.
A few weeks ago, I received an an email from a local resident, one that had been addressed to many other recipients on the local community email list. I do not recall the exact title of the email, but it was something similar to “A Magnificent Visitation.” Attached to the email was a brief video depicting a flock of several hundred birds flying in coordinated patterns over the desert. The grace and wonder of birds in flight cannot be denied. I am sure that the sender of that email had nothing but good intentions. People liked the video. One neighbor even chimed in with comments referring to her happiness at seeing so many of these same birds at her feeders.
I was alarmed when I saw the video. I immediately recognized the birds in flight as a flock of brown-headed cowbirds. This was a larger flock of that species than I had ever seen in the valley. NOT good! Allow me to explain:
Brown-headed cowbirds are nest parasites (also known as “brood parasites”). They do not build nests nor do they incubate eggs or raise their own young. Those favors come from other birds, a list that tops over 220 species, including a wide variety of our songbirds. Female cowbirds are experts at finding the nests of other birds. They quickly lay their eggs during brief times when the host birds leave their nests to feed or seek water. Most birds do not recognize the alien egg, and proceed to incubate it as their own. When the egg hatches, a tiny, blind, featherless cowbird emerges to shove any remaining eggs or previously hatched young out of the nest. It remains there alone, to be fed and fledged by its unwitting foster parents, be they sparrows, warblers, vireos, or other species like the dazzling lazuli bunting pictured above.
The original niche that nature had carved out for brown-headed cowbirds in the area we now know as the United States was that of a prairie grassland bird that was closely associated with herds of roaming bison. The bison broke up the soil with their heavy hooves as they moved, exposing a banquet of food for ground-foraging cowbirds. There were other races of cowbirds in a few other locations, such as the inter-montane grasslands of central British Columbia. However, I do not believe that brown-headed cowbirds are native to southern Arizona. They are a relatively recent introduced species, likely first appearing here when they followed large herds of cattle that were driven into the region in the 1800s by Euro-American settlers.
The story of these birds does not sound so bad until one realizes some important aspects of their ecology coupled with the plight of our declining songbirds. Brown-headed cowbirds are flying egg factories. A single female cowbird can lay up to three dozen eggs in three dozen songbird nests every year. Considering that an average songbird nest would normally raise three or more young birds, that adds up to over 100 songbirds destroyed by each female cowbird every year.
North America’s songbirds have been rapidly declining in recent decades due to a variety of factors, all caused directly or indirectly by the activities of mankind. Here in southeastern Arizona, cowbirds are impacting our dwindling bird populations seriously. Like tumbleweed, buffle grass, or other non-native species, they are capable of wreaking havoc on ecosystems like this one that they are not endemic to. As a native species, the brown-headed cowbird is protected under the Migratory Bird Treaty Act… but native to where? What ecoregions?
I won’t tell my readers how I react to the presence of cowbirds here on our property, but I’d bet some of you can guess. All life is deeply beautiful and all life should be respected and revered. As I grow older, I embrace such tenets more and more deeply, but there are times when one must act to protect certain things. I never kill rattlesnakes, for example, even the ones that commonly sleep under our ramada, but when mice get into the engine compartments of our vehicles, decisive action is essential. Brown-headed cowbirds? Never welcome here.
Late in the evening of April 17th, new sounds could be heard emanating from the surrounding mesquite bosque. Barely audible but familiar from prior years, the sounds were raspy, tremulous, unique. They were the first thin cries of hatchling ravens, born to none other than our pair of resident Chihuahuan ravens, Mike and Mavis. This new brood marks their seventh successful nesting on our property and their first in the new nest (described in my previous blog post). As always, we are honored to share habitat with these regal birds. We look forward to watching them raise and teach their young. Few North American birds spend as much time rearing and educating their young as ravens do.
The demands of a raven’s day-to-day life reach a crescendo during nesting season. After the chicks have hatched, both parent birds spend their days defending the nest from predators and making countless trips back and forth to bring food and water to their young. Nestling birds require amazing amounts of food at frequent intervals. Here, the mother raven is about to abscond with a tasty block of suet.
The past year has been the driest I have ever witnessed in southeastern Arizona. Last year’s crucial summer rains barely happened here in the Middle San Pedro River Valley, and the following winter rains were extremely sparse. The landscape is desperately dry, even for a desert, so signs of spring have been more welcome than ever. One of them appeared several weeks ago when a black swallowtail flew in to get a drink from a muddy patch of soil near one of our bird water dishes. Butterflies play very important roles in the ecology of this ecosystem. They grace our lives with their flight and their remarkable beauty.
A black swallowtail, (Papilio polyxenes), gets a drink from a patch of wet soil. Caterpillars of this species can be found primarily on plants in the parsley family.
Another sign of the changing seasons was the emergence of a beetle known as the fiery searcher. Just over an inch in length, these beetles display gorgeous coloration; an indigo-purple head, thorax, and legs with emerald green, iridescent elytra (wing coverings). This marked the first time that I have ever encountered this species here in a mesquite woodland. Usually, I find them in the riparian cottonwood-willow forests along the San Pedro River.
A fiery searcher, (Calosoma scrutator ). This insect is classified within the family Carabidae, the ground beetles. Fiery searchers are active during the day, hunting caterpillars and grubs. The species pictured here manufactures noxious chemical compounds for defense; they smell horrendous and probably taste just as bad to potential predators.
Another certain sign of spring is the emergence of reptiles. A few weeks ago, I had a surprise when I retrieved a wheelbarrow from an open shed. I always keep wheelbarrows flipped over so that rain water cannot accumulate inside and rust them out. When I flipped the wheelbarrow over, here is what I found…
This western diamondback had discovered a safe, dark place to hide in, until I needed the wheelbarrow.
I have found rattlesnakes under my wheelbarrows more than once in the past. All snakes – including rattlesnakes – are always welcome on our land. We never kill them. Once in a rare while, I will capture and move one to a safer locale, but usually I simply let them be, like this one. I do my best to respect all life!
A closer look at the formerly hidden snake. Rattlesnakes at rest almost invariably assume this characteristic, circular posture. With respect to most species, snakes can be readily identified by their markings and coloration. Rattlesnakes, gopher snakes, and many other snakes can be recognized even further, as distinct individuals. The markings on their heads and necks are individually unique, much like our fingerprints.
Yesterday, another sign of spring showed up nearby, a beautiful glossy snake. They are among the most common snakes in local mesquite bosques. Glossy snakes can reach lengths approaching four feet and feed on mice, kangaroo rats, lizards, and other snakes.
Glossy snakes are commonly mistaken for gopher snakes. One of several ways to tell them apart is that gopher snakes have keeled scales on their backs, whereas all of the scales on glossy snakes are smooth. Their technical moniker is hard to forget: Arizona elegans. The whitish object in the upper left quadrant of the image is a velvet mesquite bean.
The local stands of mesquite furnish very high quality firewood in addition to providing crucially important habitat to numerous wildlife species. Recently, a dead mesquite was felled here on our place that was threatening to crush one of our buildings if it were allowed to fall naturally. I sawed it into firewood. Other dead trees are left standing, for they are very important to many living creatures and to the health of the soil that they will eventually become a part of.
We live in an age when most adults and even our children are soft, weak, and overweight. Machines now do much of our work for us, and recreation often consists of vegetating in front of a computer screen or playing sedentary video games. A little physical work will always do a body good. I have felled, bucked, hauled, and stacked more firewood than I can ever recall. My decades in Montana always included a demand for at least eight cords of wood annually. Even here in southern Arizona, winters get chilly and a warm wood stove can be a real comfort on frosty nights.
“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.
Behold the common poorwill, the only bird on Earth known to hibernate! My first acquaintance with this fascinating creature happened in the late ‘80s. At the time, I was living in an old log cabin nestled into the stony folds of Montana’s Rocky Mountain Front. There, I heard an unmistakable signature call lilting out of dusk-wrapped foothills on warm summer nights, a plaintive two-note call that to some, sounds like “poor – will.”
Summer after summer, I heard their voices – sometimes I would glimpse one in flight. Much about poorwills remained a mystery to me, until one fateful evening. As I was driving up a dirt road, a small bird abruptly rose up in front of my pickup truck. The resulting collision was unavoidable. I stopped immediately, dismayed to find an inanimate lump of feathers caught in the grill. Gently, I extricated the bird and gazed at its limp form in wonder; cupped in one hand, its warm feathers felt gossamer-soft. My attention was immediately drawn to its head, quite large relative to the rest of the body. Two huge, liquid eyes characterized the bird’s visage. What looked like a ridiculously tiny beak barely poked out from a covering of feathers. The area around the beak (and the rest of the bird’s hidden mouth) was festooned with a fringe of curved, jet black, semi-rigid bristles.
Now it gets even weirder. I had read up on these birds, so I knew that they were grouped in a strange family known by several names: frogmouths, nightjars, or goatsuckers. (Yes, goatsuckers, but that is another story altogether.) Curious, (as any naturalist should be) I pried the beak apart. My jaw fell in synchrony with the yawning beak, for the beak did not merely open; the bird’s head nearly split in two! The hidden edges of the beak extended far back to form an absolute cave of a mouth, a great, gaping maw that could make any shark jealous. Why such a mega-mouth, and what was with those bizarre bristles?
Poorwills are highly specialized to feed on flying insects in low-light conditions. Having a wide gullet for a mouth makes it much easier to catch insects on the wing. Their heads are unusually large because plenty of room is needed to house the mouth and a pair of very large eye orbits. Big eyes gather more light, handy for spotting prey in the dark.
Here at the interface of the Sonoran and Chihuahuan Deserts, habitat like this is well suited for poorwills. A scattering of low shrubs, cacti, and plenty of open ground in between provides these amazing birds with unobstructed views and open flight paths to help them catch flying insects.
Some ornithologists speculate that the stiff bristles form a sort of tactile net around the mouth, effectively enlarging the bird’s open mouth. This increases a poorwill’s chances of success when chasing its evasive flying food. During the heat of summer, these desert-dwelling birds reveal another advantage enabled by their gigantic oral cavities. As they roost during hot days, poorwills open their mouths while fluttering the muscles in their throats, cooling themselves in a manner similar to a panting dog. The efficiency of such a cooling method is substantially amplified due to the large surface area of the bird’s mouth.
A close look at a poorwill’s head reveals the long rictal bristles that fringe their mouths.
So what about poorwills and hibernation? Here, in the Sonoran and Chihuahuan Deserts, poorwills crawl into rock crevices where they go into a state of hibernation or extended torpor (these terms remain somewhat ambiguous) for months during the winter. Their respiratory rate and heartbeat drops substantially, while their body temperature plummets to nearly 40° F.! An astute scientist is credited with “discovering” that poorwills hibernate as he conducted research on them in 1948. However, indigenous peoples knew this long before 1948. For example, the Hopi Indian word for poorwill is (roughly) hölchoko, translated as “the sleeping one.” Thus, much like Columbus, the 1948 discovery simply revealed knowledge to a different culture, knowledge that was already known to another. (With respect to Christopher Columbus, it is impossible to “discover” a place where people already live. A combination of cultural condescension and arrogance can imprint our history books with less than the truth.)
There is much more about poorwills that makes them such captivating, beguiling birds. Their camouflage is utterly incredible. Poorwills roost on the ground where they literally merge with their surroundings. The cryptic patterning of their plumage renders them extremely difficult to spot. On more than one occasion, I have nearly stepped on them before they revealed themselves through movement. The genus name for poorwills is Phalaenoptilus, ancient Greek for “moth plumage.” (Our birds are a very unique species, for no other bird on the planet shares their genus epithet.) The scientific name Phalaenoptilus is fitting in two ways, for many moths are extremely well camouflaged, and moths make up a large part of a poorwill’s diet.
Don’t let the red eyes fool you! This is an artifact of the light projected by a camera flash. When seen in natural light, the eyes of poorwills are very deep brown or black in color. Read the following paragraph for more details.
Like other members of their family, poorwills possess a special layer of cells at the back of their huge eyes known as the tapetum lucidum, rarely found in other birds. These cells allow them to see much better in low-light conditions. As for the glowing red eye in the photographs, that results from light reflected from the choroid, a thin layer of connective tissue surrounding the outer periphery of the eye. The choroid is nourished by a rich supply of capillary blood vessels, hence the red color. (The “red eye effect” sometimes seen in photographs of people is caused by similar choroid reflectivity.)
Weird enough? Not quite. On the Montana evening when I held the unfortunate poorwill in my hand, I had missed something: the bird’s feet. Poorwills possess pectinated claws (one per foot) with comb-like, serrated ridges that are used to preen plumage and to rearrange the rictal bristles. There is also the fact that these birds do not build nests – they simply lay their whitish, non-camouflaged eggs on the open ground. How they manage to keep their species alive via such seemingly risky egg-laying habits may seem enigmatic, but it works, for there are poorwills year after year. Here in the uplands and mesquite bosques of the San Pedro River Valley, their lonely calls are an intrinsic part of the desert’s twilight world.
Finally, a note on the poorwill images: they were photographed recently here in Cochise County, AZ, then generously supplied by a friend for use in this blog. Unless otherwise noted, all other photographs posted on this site are original copyrighted images by the author.
Among the most important components that power the machinery of forest life are insects – beetles in particular play crucial ecological roles in forests. One of the largest beetle families is the Buprestidae, represented by nearly 16,000 species. These creatures are known as “jewel beetles” due to their family’s spectacular array of iridescent colors and patterns. The insect pictured above is one dazzling example, native to the coniferous forests of the Rocky Mountains.
One of the world’s largest jewel beetles is Euchroma gigantea, native to Amazonia. These insects can measure over two inches in length. This is a mounted specimen from Brazil, part of the author’s collection.
In most living organisms, iridescence is enabled by pigmentation. Jewel beetles are different – their iridescence is structural in origin; microscopic texturing on the surfaces of their exoskeletons selectively reflects specific frequencies of light while absorbing others.
Most jewel beetles lay their eggs on dead or dying trees. Once the eggs hatch, the beetle larvae go to work, chewing their way through the wood. They leave a maze of tunnels in their wake. Some species of jewel beetles will lay their eggs only on freshly burned trees. These specialized insects are known as pyrophiles (literally, “fire loving”). Forest fires create a nearly instant Shagri-la for them.
The larvae (or grub) of a jewel beetle found inside a section of velvet mesquite wood. These larvae are often known as flathead borers due to the shape of their heads. The tunnels that such larvae create in dead wood are of great importance to forest ecology.
Pyrophilous jewel beetles have evolved specialized extra-large wing muscles to enable long distance flights to wildfire sites. These beetles have a way of finding burned trees that borders on the miraculous…
One of the buprestid beetles native to velvet mesquite bosques in southeastern Arizona. Note the heavyset, thickened body of this insect, a specialized morphology that allows room for large, powerful flight musculature.
When they fly, these beetles hold their bodies at an angle, in order to orient their underside to the direction of travel. Minuscule texturing on the ventral side of the insect’s thorax functions mechanically in response to incredibly faint traces of infrared radiation (heat). Infrared radiation causes a pressure differential to occur in the thorax texturing. This fires neurons, sending a message to the beetle’s brain. The message says “fly in this direction and you will find a smorgasbord of freshly killed trees to provide food for your offspring.” What is even more amazing is that these insects can detect the heat given off by fires at distances up to fifty miles! (research conducted by Dr. H.P. Bustami and associates at the University of Bonn [in Germany] brought this astounding facet of jewel beetle biology to light.)
A living jewel adorned with iridescent gold flecks and shimmering purple-sapphire elytra, this native buprestid inhabits local mesquite bosque habitats.
This relationship between forests, fire, and beetles has been going on for countless millennia. However, people often take a dim view of beetle larvae drilling tunnels in trees, claiming that this ruins otherwise “valuable” wood. Such anthropocentric views are myopic, for they exclude the needs of all other living things and turn a blind eye toward the ecology of forests. Jewel beetles benefit forests as agents of decomposition; the tunnels that their larvae bore in dead trees provide important open pathways for other insects and for the introduction of fungal spores. The tunnels facilitate the exchange of gasses in the wood and furnish the perfect moist, insulated, dark environ for fungi to take hold. Fungi are crucially important to living trees, to the health of the soil, and for their leading role in the recycling of nutrients via the decomposition of dead trees and other organic detritus. No forest on Earth can exist without fungi and decomposition.
This maze of tunnels was bored by jewel beetle grubs in a dead limb on a living velvet mesquite tree. Read the text above to discover why these tunnels are so beneficial to forest ecology.This is a limb that was cut from the same tree as the one in the preceding image. However, this limb was cut when it was alive. Note the scarcity of holes and tunnels. Most jewel beetles lay their eggs only on dead wood, but there are a few exceptions to this rule.
Here in the desert southwest, jewel beetles are usually easy to find almost any place where trees are present. I have also found them rather often in upland desert habitats – areas that are essentially treeless. Buprestid beetles fly into these places seeking nectar and pollen meals from the wildflowers and flowering shrubs that grow there. Thus, they provide another important ecological function by acting as pollinators.
A few months ago, an unfamiliar bird call became part of the daily biophony here on our home acreage in the Middle San Pedro Valley. As an ever-curious naturalist, I had to know what bird was uttering those strange calls. My wife, Kathleen, had noticed it too. The bird called frequently in the early and late hours of every day, taunting us with its unique, three-note call.
Binoculars in hand, I went looking. I slowly approached in the direction of the sounds, looking patiently and carefully. The local habitat consists of a mature forest of velvet mesquite trees. The sound seemed to be originating up in those trees, but no matter how much I searched, the bird remained unseen. Most often, as I approached too closely, the mystery bird would exit stage left and start calling from a new, more distant location. I tried on another day, and another. Every time, the maker of the calls remained elusive and sequestered.
Velvet mesquite bosque, the woodland where the mystery bird appeared. This is an image from the summer months.
One morning, after hearing the unseen bird again, Kathleen and I decided it was time to explore the xeno-canto website. I know of no better website when it comes to searching for bird sounds; readers can find it here: https://www.xeno-canto.org
I had a growing hunch that we were hearing a thrasher…when we listened to the recordings of crissal thrashers, both of knew that the enigma had been solved.
The crissal thrasher visiting our bird bath on a cold morning when the water had frozen solid. Crissal thrashers average 11 1/2 inches in length. This species is known to form pair bonds (in preparation for the spring breeding season) as early as January. Just two days ago, I noticed that our thrasher had found a companion…
Why hadn’t I seen the bird? I had been looking up in the trees when I should have been looking down, at or very near ground level. The bird seemed to have the ability to “throw” its voice, making the calls sound like they were coming from above. Once we had learned the identity of the bird, we realized that we should have been searching for it on the ground, not up in the trees. Now, we see the thrasher every day as it hides beneath graythorn bushes, foraging for food.
Graythorn is indeed very thorny. Meant to discourage consumption by mammals, the thorns protect the plant, but when it comes to birds, these thorns are an attraction. They spell security from predators, especially raptors.
Crissal thrashers spend much of their time beneath thick cover, using their long, decurved bills to dig and rake away soil and duff in search of insectivorous food. Locally, these birds appear to have a very strong connection with graythorn bushes. Graythorn (Ziziphus obtusifolia) is the most common understory shrub in local mesquite bosques. It grows dense, tangled, thorny foliage, furnishing the perfect place for shy birds to seek cover in. I cannot overstate the ecological importance of these plants with respect to bird life. Many species of birds hide in graythorns, feed from the plant’s abundant berries, or nest deep within its thorn jungle of tangled branches.
At the time of this writing, the graythorn bushes outside my windows are in full flower. The blossoms are minuscule.After the flowers have been pollinated, berries grow on the graythorn bushes, providing an important food source for many local birds and mammals.
This winter, the Middle San Pedro Valley has been inundated with unprecedented numbers of white-crowned sparrows. There are hundreds on our land every day, and in many other places as well. I cannot walk by any graythorn bush without flushing a throng of white-crowns from within. Like the thrasher, they forage on the ground and use graythorns for cover. Security is imperative to all small birds here, for bird-hunting Cooper’s hawks are present almost every day.
The promise of coming vaccinations, a new president, and the start of a new year have me full of hope… a state of mind that had faded considerably during 2020, a year marked by tragedy, social division, societal unrest, and a steadily worsening global pandemic.
Here in the Middle San Pedro Valley, the season of winter is at hand, although the use of a term like “winter” in a place like this is a stretch of the word. The coldest temperature I have ever experienced here was only 8°F., and snow rarely falls in the valley floor. The image above was taken on a winter morning when a rare blanket of fog had smothered the riverbottom forest with its cool, moist embrace. Fog is almost as rare as snow here. When fog does occur, it is a very transient affair, for desert fog most often dissipates into invisibility very quickly as the day warms.
A full moon casts its light on a stand of winter saguaros.
A few years ago, five inches of fresh snow fell overnight, gracing our bosque with a mantle of gleaming, sparkling white. I could not resist taking an early morning walk in order to read the very best of nature’s newspapers, for the goings on of every bird and mammal were written plainly in the snow. I encountered fresh tracks of various songbirds, quail, coyotes, a raccoon, mule deer, javelina, mice, cottontails, jackrabbits, and more. Following a set of roadrunner tracks (they are quite distinctive) I came across a sight I had never seen before: a roadrunner perched in a snow-covered mesquite tree.
I met with this well-chilled roadrunner perched in a velvet mesquite tree on a snow-graced morning.
Nature has forever been a source of inspiration for artists. There are scenes along the San Pedro River that could captivate any artist’s mind. Last month, an unforgettable gift arrived in our mail, an original painting crafted by none other than my brother, Rick. He and I had spent some time hiking in the riverbottom woodlands one fine spring day, when the river was alive with color and light. We stopped for a break at one of my favorite spots, a place that left its mark in my brother’s memory. Rick captured the essence of that place beautifully in this painting. What a gift!
