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Dawn splashes amber light over the vertical stripes of marsh plants all around me, illuminating the intricately patterned bodies of two silhouettes in a dead cottonwood tree above my head. The silhouettes swivel their heads to look down at me. Razor claws gripping dead branches and golden eyes drooping with sleepiness, they perk up at the hoots of a distant neighboring pair. The male stands up on his perch, leans forward, almost as if he is going to somersault into the marsh, and puffs his white-feathered throat, letting out a low, booming answer. The female joins in with slightly higher-pitched hoots and few cranky yelps. Then they retreat into a huge thorny mesquite where they will doze in the shade until dusk falls and hunger draws them out again. Their nightly pursuits are written in the sand each morning.

If you've never spent much time in the desert, or especially if the only time you have spent is staring out the car window blasting down the interstate at 85mph, you might be tempted to believe there's nothing but a lifeless wasteland out there. Endless shades of brown – tawny sand, rust-tinged hills, dusty mountains carved by winding dry riverbeds, scraggly plants barely squeezing any green into the landscape. Aside from a few wheeling ravens, and ramshackle trailers that may or may not still be occupied by snowbirds, signs of life are slim. That is, until you pull your car over to the shoulder and step into a dry wash to relieve yourself (the nearest gas station still 80 miles away). The glaring sun keeps your eyes low, and scanning the cracked earth you discover a foreign language scrawled across the sand.

 

I'm standing knee-deep in a crystal clear marsh, but up beyond the bank is a sparse mesquite bosque, each sand-marooned shrub wreathed by tiny footprints – the paired dots of bouncing kangaroo rats, galloping four-paws of desert pocket mice and cottontails, patterned tick-marks of little grasshopper feet, and even the unusual squat-stamps of toads. The night crew of the desert. Alongside the pitter-patter, larger tracks trundle across the open sand, sometimes interrupted by dug holes and messy attacks– coyote, bobcat, raccoon, skunk, and Great Horned Owl. The owl tracks are unmistakable - longer than my forefinger with two toes pointing forward, one pointing back, and one sticking straight out to the side. Owls are what ornithologists call zygodactyl – their inner front toe able to swivel to the back, maximizing the surface area of deadly talon potential during an aerial pounce. The sand here is so fine, I even found a full-spread wing imprint of an owl touching down. But wait, you say, do owls really walk on the ground? These ones apparently do, quite a lot, as evidenced by their sloppy gait traced across the dunes. By the time I arrive at dawn to survey for avian life, the authors of all these stories have tucked in to their burrows, tunnels, and hiding places under dense brush. 

 POUNCE!

 

Five years ago, this whole area – the marsh, the mesquite – was a sea of tamarisk. This water-guzzling shrub, also known as salt cedar, was introduced to the west in the 19^th century for erosion control as the Colorado river was being dammed, rerouted, channelized, and sucked dry. The trees spread quickly in the upturned earth and now chokes the banks of much of what remains of the Lower Colorado. Tamarisk exemplifies all the worst weed characteristics you can imagine – it grows quickly (up to 12 feet in a season), reproduces generously (one tree can produce 600,000 seeds annually), colonizes disturbed earth rapidly, and spreads by the one method you can't control: wind. The roots suck up and retain water and exude massive amounts of salt, changing the composition of the soil to levels unsuitable for most native riparian plants, thereby creating vast monoculture stands, deprived of birdsong, scurrying rodents, or sun-bathing reptiles. And worst of all, tamarisk is virtually un-killable: it resprouts vigorously from cut stumps, after fire, and even herbicide treatment. In other words, its a BIG problem for conservationists in the west, especially in riparian areas of the Southwest that have been dismantled by development.

 

 An inspiring scene from recreational Park Moabi, north of Lake Havasu City, with tamarisk in the background.

 

Not surprisingly, I don't have many photos of tamarisk itself. I think I took this one because I was so startled to find another kind of plant struggling for life beneath the deadly shroud of tamarisk canopy (center bottom).

Sunrise reflecting in irrigation canal, Blythe CA. Notice anything missing? Plants perhaps?

Habitat for local wildlife has been shrinking and fragmenting for centuries, and the effects reach further than the desert. Before industry started rearranging the river for its own purposes, migrating birds like warblers, vireos, and flycatchers followed green ribbons north through deserts and dry sagebrush basins, thousands of miles of verdant cottonwood-lined river valleys from Mexico to the Northwest and boreal Canada. Now there are a few struggling islands of original riparian habitat left, meaning these tiny birds have to fly further across those barren bajadas to find fewer resources during their epic biannual journeys. 

 The resplendent Bill Williams National Wildlife Refuge, one of the last remaining stands of riparian forest along the Lower Colorado. Just try to imagine this snaking all the way up from Mexico to the Grand Canyon.

But all is not lost. For the last three decades, coalitions of federal, state, tribal and conservation groups, including the Bureau of Reclamation, have been developing a methodology to convert reclaimed land along the Lower Colorado back into riparian habitat. Old farm fields no longer in production are replanted with native cottonwoods, willows, mesquite and marsh plants, and irrigated on an intermittent schedule to mimic historic flood cycles. Each project is an experiment with varying results. Some plots attract migratory and breeding birds while others seem to repel them, and factors change over time as trees grow and are thinned. Each project provides lessons on what works and what doesn't. And this is where nonprofit Great Basin Bird Observatory comes in.

For the past 5 years, GBBO has been leading the breeding bird surveys along the Lower Colorado for what's called the Lower Colorado River Multi-Species Conservation Plan. Through on-the-ground surveys and data analysis, GBBO documents the use of virgin, disturbed, and created riparian habitat by breeding and migratory birds. Each spring, GBBO sends out intrepid field crews to riparian plots around Yuma, Blythe, Lake Havasu City and Lake Mead to conduct area search and spot-mapping surveys of bird activity, with a focus on six of the more-imperiled passerine species. Other agencies and crews monitor endangered populations like Yellow-billed Cuckoo, Southwest Willow Flycatcher and Elf Owl. Then in the fall, GBBO conducts extensive vegetation surveys to link the bird data with environmental conditions. The analysis of this data contributes to current and future management plans.

4am wake-up call never gets easy, but dawn never gets old.

And this is where I come in. This is my third spring season with GBBO's LCR crew. The first year I was hired, I was living in Maryland and looked forward to hiking among dry dunes and cacti. Contrarily, the LCR surveys are some of the wettest I've ever participated in! It's true, I've yet to be caught in a rainstorm. But with the intermittent water flows, I never know when I am going to be knee-, thigh-, or even chest-deep in marsh water. I've even had the pleasure of surveying by kayak!

Today, the marsh seems to be lowering. Last week I was tip-toeing through a channel with my pack above my head. Now crystal-clear puddles are surrounded by thick mud. I am stationed in Yuma, Arizona to survey two big habitat creation projects: Yuma East Wetlands on the north-east edge of town, and Laguna Division Conservation Area about 20 miles up river, straddling the California-Arizona border. Yuma East is older, with some nice big cottonwood stands, plenty of bird-life and even a resident bobcat. LDCA is brand new, a baby habitat growing up fast. In 2011, the tamarisk sea was bulldozed and re-graded to create winding channels, varied slopes for ecotones, and larger bowls of open water for wintering ducks and future recreational fishing. Water delivery and control systems were constructed to direct water in what are called “pulses”, from Imperial Dam at the north end and back to the grid through Laguna Dam at the south. The next season, marsh plants and tiny saplings were planted by these crazy machines that look like 4-driver tuktuks with a harvester on the back, but instead of harvesting, it inserts baby trees into the ground. With this new technology, the painstaking process of hand-planting trees has been reduced to 10% of the time and energy once necessary.

Black Phoebe nest built against the wall of a water delivery canal, LDCA.

By the time I arrived early in April 2016, the marsh areas were fully grown and humming with the sewing-machine songs of Marsh Wrens, witchity-witchity of Common Yellow-throats, hilarious guffawing of Yellow-headed Blackbirds, and terrifying growling of Great and Snowy egrets, White-faced Ibis, and Black-crowned Night Herons. Cormorants were sunbathing and an osprey was fishing from dead snags left purposefully by the dozer crews. A beaver slapped the water in warning and fish darted in the shallows. The trees are still young, some just reaching above my head. They were arranged in sweeping rows with willows lining the waterways, cottonwoods above them, and mesquite and desert riparian grasses on the drier islands. As I weave between the glowing deciduous leaves, the air is relatively quiet, except for the bombs going off in the hills to the east. On the other side of Mittry Lake lies Yuma Proving Ground, and often my “flyovers” category could include all manner of mechanical birds, not to mention paratroopers floating on the horizon. In the midst of current global affairs, I feel a sense of bittersweet privilege, certain that the explosions are practice and not intended for me. It makes my heart go out to all those for whom that certainty is not reality. 

The current lack of birds in the young “forest” is not in the least disheartening, though! In fact, all that photosynthesizing lends an excitement to the air, I can almost taste the potential in the wafting pollen. This liminal habitat may be quiet now, but in a few years I can envision a winding row of towering cottonwoods ringing with Yellow Warblers and willow thickets so dense only small creatures seeking shelter can enter. If Yuma East Wetlands can be used as a gauge, the future is hopeful. Just across the highway from downtown, you can be transported into a wildlife wonderland. Bobcats, mule deer, Gambel's quail, legions of lizards, even a few rattlesnakes dart among the well-crafted shrubland and forest plots. Marshy ponds harbor rails and herons, and flocks of thousands of migrating swallows roost among cattails for the night. The magic is only interrupted by winks of human design – concrete canals slicing through cottonwood groves or sputtering irrigation tubes winding around mesquites and ground-squirrel burrows. This sort of cyborg nature seems slightly disingenuous – wilderness on life-support – until you witness the results in blossoming biodiversity.

As I sneak along the drying mud in LDCA, eyes scanning the ground for nighthawks, I see millions of mammal and heron tracks – the collective treading of animals over the past three years laid upon one another, never fully washed away by the gently rising and falling water levels. Signs that wildlife are already filtering in to this new opportunity. A barely-audible flickering tickles my right ear, and in my peripheral vision I catch the frantic flapping of a female Lesser Nighthawk. Her Oscar-worthy performance of broken wings and seizures momentarily draws my attention away from her two speckled eggs, laid directly on the sand. Their camouflage is impeccable, and if it weren't for the nighthawks' undying parental devotion, I would worry about accidentally stepping on them. The nocturnal birds spend all day shading their precious investments on exposed gravel bars, even bringing water from nearby sources in their breast feathers to sprinkle on eggs that could go from developing to sunny-side up in sizzling ground temperatures – sometimes up to 20 degrees hotter than Yuma's average triple-digit highs. I take a quick snapshot of the eggs and move on, careful not to leave a dead-end scent trail. Within seconds, the mother is back on her “nest” – more conceptual than practical, but it must work often enough!

 Lesser Nighthawk's meticulously crafted nest.

Water is life on earth, but it is no more painstakingly obvious than in the desert. Parched by sun and wind, any bit of water effects the plants and animals for miles around. The humidity created by deciduous transpiration effects valley temperatures and weather patterns. A hundred miles upstream, the Colorado is fed by the Bill Williams River, one of the last remaining stands of riparian forest. It is now a Wildlife Refuge, and harbors thirty-four species of butterfly – eleven of which were historically common throughout the river system, but are now only found there. Even elusive creatures that spend most of their time on the dry ridges – bighorn sheep, mountain lion, and ravens – come down to the valleys and springs to fill their gullets with life-saving liquid.

Dams and irrigation have created a lot of opportunity for humans in the forms of agriculture, development, and energy. It's heartening to know that its possible to give back a little to the other residents of this verdant desert corridor. It takes a lot of work but it is proving to be worth every drop. I can't wait to come back in a few years and see the habitats all grown up!

 Great Horned Owl... or desert penguin?

This essay was originally written for the Great Basin Bird Observatory blog, which you can read here: http://gbbofieldnotes.blogspot.com/