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.”
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.”
