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
19th 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.
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.
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/
