Le Conte's Thrasher male with insect
Le Conte's Thrasher male with insect
As the urban sprawl that is metro Phoenix finally begins to recede in your rearview mirror and you roll out I-10 toward California, the only remarkable thing about the Low Sonoran Desert landscape is its unremarkableness.  I’m not a plant guy, but I think there is Brittlebush, Saltbush, and some species of sage, Rabbitbrush and the occasional Black-tailed Jackrabbit.  There is Wolfberry but no wolves, only the occasional Coyote.  Along the dry washes, where water might run after the female rains of winter’s Pacific fronts, and where water will run after the male rains of summer’s monsoons, there is an occasional strand of stunted Palo Verde.  There is Prickly Pear Cactus and the occasional Ocotillo.  Somewhere Mohave Rattlesnakes warm up in the spring sunshine, and there are Dung Beetles which, contrary to what you’ve heard about Coyotes and Cockroaches, will surely inherit the earth after the nuclear apocalypse.

The desert here is the one Easterners who haven’t been west imagine to their children.  There is little topographical relief, no water, and every living thing is adorned with thorns.  The background color is pale khaki, but of course this desert floor is not sand, just dusty dirt the color of sand.  Sand is also the background color of Le Conte’s Thrasher plumage, befitting a bird exquisitely evolved to make a living in this wasteland, and Le Conte’s Thrasher is the only avian species that brings birders to this wasteland.  There are gnatcatchers and Verdin here and, when the Sage Thrashers pass through in March on their way north, three other flavors of thrashers.  I’ve seen Prairie Falcons and Northern Harriers here in winter on their way to happier hunting grounds, but there is nothing here, save Le Conte’s Thrasher, that a birder can’t find more easily elsewhere in more hospitable, user friendly habitat.

This Le Conte’s habitat runs westward from Phoenix all the way to the Colorado River, but because birders are like sheep and follow one another around, they concentrate their efforts to see Le Conte’s just west of Phoenix at the intersection of Baseline Road and the Salome Highway, a place so well known in the birding literature it has come to be called simply “The Thrasher Site.”  Just west of The Thrasher Site is a series of low hills, and as the birder’s eye wanders down the stunted strand of Palo Verde marking the course of the wash that is the continuation of Baseline, it is arrested by plumes of smoke rising up, starkly white against the lapis lazuli desert sky, from behind these hills.  These are the emission plumes from the other Palo Verde, the Palo Verde nuclear facility, a surreal reminder of just what a wasteland the desert here is deemed to be.

The Palo Verde plant is here because nothing else is here.  The theory in the beginning, of course, was that if there was a malfunction or a meltdown, metro Phoenix was far enough removed that no humans would be in danger.  I’d venture to guess not a single thought was given to the Le Conte’s Thrashers, the jackrabbits, or the Dung Beetles that actually live here, foraging beneath the Palo Verde trees in the shadow of the Palo Verde facility.  But Phoenix is sprawling westward and earthquakes still rattle the Pacific’s tectonic plates, so now we all live in the shadow of Fukushima, figuratively if not literally.

A decade or so ago, during the Arizona Breeding Bird Atlas years, there was a story circulating, apparently apochryphal, that the ABBA surveyors were the first researchers to ever find a Le Conte’s Thrasher nest.  Last week Diane Touret, an avid and excellent birder from Tucson, reported one here at The Thrasher Site and, intrigued by her find, I’ve come out to look for myself.  In my birding lifetime I’ve stumbled by sheer dumb luck upon two Crissal Thrasher nests, both so well hidden their shape was difficult to discern even as I stood right next to the bushes which concealed them.  Le Conte’s are reputed to be even more secretive around their nests than Crissals, their nests impossible to discover.

I am fairly familiar with Le Conte’s because I used to lead a Maricopa Audubon Society field trip to The Thrasher Site every year.  I recognize their song.  It is the softly, sweetly whistled melody that ebbs and flows announcing dawnlight in January and February.  I know how to look for them.  They run the “sand corridors” in and out between the green- bushes-with-no-name, black tails cocked up exposing the peach-colored vent which glows salmon with the sunlight.  They run like roadrunners, and they run with the Sage Sparrows that overwinter here. 

I’ve made every thrasher identification error, most egregiously mistaking Le Conte’s for both Crissal and Bendire’s, their thrasher congeners who share this wasteland but are also found in many other habitats.  You’d think it should be easy—the dark eye, the pale-as-sand background color, the unmarked breast, the contrasty black tail, and the more richly colored vent, still pale in comparison to other thrasher vents.  Le Conte’s identification is the sum of these five pieces, but there is no accounting for even an experienced birder’s Le Conte’s anxiety, the angle and intensity of the light, and the ability of all thrashers to flit and run which allows a birder only a glimpse of any of these five pieces.

If you’re a sports fan, specifically basketball, and you’re into size visuals, here’s a fun exercise.  Sage Thrasher, Arizona’s smallest thrasher, is the point guard.  Bendire’s, slightly larger and more robust than Sage, is the “two,” the shooting guard.  Le Conte’s, to me bigger, lankier, but not as plump as Bendire’s, is the “three,” the small forward, the best runner/slasher on the thrasher team.  And Le Conte’s is a runner/slasher.  Good luck getting a long, satisfying look at the complete package.  Crissal, bigger still and with that stiletto bill, is the power forward.  Curve-billed, your backyard and city park thrasher, is the largest, the center or post man.  I have never seen a Curve-billed at The Thrasher Site, but I was once flamed on the internet for doubting that another birder had.  It cured me forever of questioning any other birder’s identification.  Publicly.

Not once, though, did I doubt Diane’s report.  I know her to be a careful, observant birder interested in the life histories of her subjects rather than a checkmark on some list, and I appreciated the fact that she described the nest but did not give specific directions to it, precluding any undue nest disturbance.  Truth be told however, a thrasher nest needle in this gray green featureless Sonoran desert haystack would be almost impossible to find, even with good verbal directions.

Not much is known about Le Conte’s Thrasher lifestyle.  One thing we know is that they sing in the early morning in January and February when territories are being established, then typically stop singing once nesting begins.  Birders look for them when they are known to be singing because the easiest way of finding one is by ear.  When breeding season is over Le Conte’s stop singing but they don’t go anywhere.  Birders who have retained their sanity, and a few of my closer friends might include me in that number, do not venture into Le Conte’s habitat during the dog days of summer, roughly May through September.  I’ve found them as early as October and as late as mid-April, but I’ve never looked in between.

There are three ways to find a bird’s nest:  see a bird with nesting material or food for its young and follow it; learn a bird’s preferred habitat and search it meticulously; be randomly lucky.  Assuming I’d never find one, I’ve never looked for a Le Conte’s nest.  Even within its breeding season birders just looking for the bird itself are often unsuccessful.  What struck me about Diane Touret’s report was that she probably wasn’t looking for a nest either, but had stumbled upon one because she was in the right habitat at the right time in the bird’s nesting cycle.  I realized my field trips had always been in the first two months of the year, never in March when nesting was taking place.

Two hours into my March Le Conte’s search I have seen zero thrashers.  Then, inexplicably, a Le Conte’s finds me.  I am standing around cussing Diane Touret and contemplating going home when a thrasher flies into the top of a nearby bush and looks at me as if it were contemplating whether to go to its home with me standing around so close.  Unbelievably enough It is a Le Conte’s, and it has caterpillars in its bill.  Okay, I am in the right habitat, but this qualifies as randomly lucky.  I freeze, it flies, I follow.  I lose it two “sand” corridors to the east, sit down and wait.  Ten minutes later it or its mate reappears with something indescribable in its bill and dives into a Wolfberry bush so dense it seems impossible a bird that big could penetrate its greenery.

I sit and watch.  I realize the thrashers must have an alternate entrance to the Wolfberry because on multiple occasions I see them exit the top without have seen them come in.  The nest itself must be deep in the bowels of the bush, invisible to prying eyes and inaccessible to predators.  I move around to the other side of the bush, sit and wait partially obscured by other bushes-with-no-name along a sand corridor there.  Within minutes an adult runs across the corridor, something in its bill, pauses, then leaps upward into the Wolfberry.  I wait until I see it leave, then I leave knowing I will be back tomorrow at first light.

The next morning I sit on the desert floor in full camouflage, partially concealed by a bush, telephoto lens and tripod before me on the ground breaking up my outline, trying not to move or even breathe when the thrashers are about.  In four hours I observe twenty-four trips to the nest, presumably male and female both because, though the birds are indistinguishable to me, one always exits from the bottom of the Wolfberry and runs away down the sand corridor whereas the other always exits from the top of the Wolfberry, flyhops up an adjacent mesquite to a singing post, emits a few phrases of the Le Conte’s “whisper song,” then flies off.  Male high, female low.

Prey items for Le Conte’s nestlings this morning include caterpillars, unmentionable looking globs of something, egg sacs, and grasshoppers in descending order of frequency and then, on the last visit a surprise—a scorpion.  I think the bearer is the female.  She beats the scorpion on the ground many times, presumably to dislodge the stinger, than hops upward into the nest.  Scorpion is another species near the top of the leader board in polls that guess who shall inherit the earth after the nuclear holocaust.  This ironic thought makes me, once again, glance nervously over my shoulder at Palo Verde’s plumes.  The tsunami and Fukushima happened one week ago today.

I see no evidence of fecal sac removal from the nest, leading me to think the young are close to fledging and, sure enough, on a visit five days later there is no activity around the nest.  Remembering Diane’s description of her nest, I am positive the nest I discovered is a different one and that the nestlings in hers are at a much earlier stage.  With no specific directions, but through the filter of her nest description, I begin a thorough search for likely looking bushes and within half an hour receive my second shock of the week.  I find Diane’s nest.

This second nest is completely different.  Mine was four feet off the ground but hidden deep within dense, green vegetation, impossible to see from any angle or direction.  Diane’s is four feet off the ground but totally exposed in a scraggly, leafless Palo Verde But, it is “camouflaged” so to speak by the fact that it appears to be just a large accumulation of twigs and bark detritus caught in a crotch of the tree, easily overlooked.  Indeed, I had passed right by it several times in my meanderings and hadn’t looked twice until I happened by during a food delivery.  My nest was a small cup of large, coarse twigs.  Diane’s nest is a large cup of small, fine twigs.  The common denominator is that there is no way for a mammalian predator to get into either nest without impaling itself or cutting itself to shreds--every living thing adorned with thorns.

There are three nestlings here, so small that although the nest is quite visible now that I know it is there, I cannot get close enough due to the surrounding thorny branches to even see them until they clamber upward when a parent comes with food.  I observe incubation, and both parents remove fecal sacs after nearly all deliveries.  There are twenty visits in two hours and both parents enter the nest from the ground on the far side of the tree where the cover is densest, flyhopping surreptitiously up to the nest.

In the background the plumes from Palo Verde lie starkly silver against the vibrant blue of the Arizona sky, all the more startling because they were not evident when I arrived at The Thrasher Site this morning.  Odd to be observing the life cycle of a species exquisitely evolved to thrive in the planet’s harshest environment while contemplating the demise scenario of a species that may unwittingly take that planet and itself backward in time.

Le Conte's Thrasher female removing fecal sac
Le Conte's Thrasher female removing fecal sac