Wednesday, February 13, 2019

California Waters: Frogs of the Frozen Reaches ---Guest Post---

Part III, and III.

More than an experiment

Sierra Nevada Yellow-legged Frog (Rana sierrae).
Photo courtesy Gary Nafis
In the 1990s, researchers embarked on an ambitious plan to restore Mountain Yellow-legged Frogs to California’s highest lakes.

The Mountain Yellow-legged Frog (now split into two species) was once the most numerous vertebrate in the Sierra Nevada Mountains. The steep streams that pour off the Sierra Nevada’s slopes are a barrier to fish movement, so frogs thrived in the empty niche. Early surveyors said the lakeshores were so thick with frogs that it was impossible to avoid stepping on them as you walked.

But sometime around the 1960s their populations began to crash. Basins which historically had been full of the frogs now held few, often none at all. Soon they were gone from 95% of their former range.

Topography keeps the Sierras wild,
but we still find ways to impact its wildlife.
Theories proliferated as to what was behind the decline. A few researchers suggested that increased UV radiation from the weakened ozone layer could be the issue, while others found a correlation between struggling frog populations and vehicular pollution. Some hypothesized that a novel disease had hit the frogs. Pesticide exposure may have been a factor, as the worst-hit populations were downwind of the intensively farmed Central Valley.

By the nineties the bulk of researchers had coalesced around one primary theory: introduced trout were eating the frogs to extinction.


Surveying a deserted landscape

Flash forward to May 2018. I had spent ten days surveying the deserts of eastern California and was ready to move on to the forests that form the backbone of the state. With my father I traveled through the San Bernardino Mountains, the San Gabriels, the Tehachapis, Breckenridge, and up into the southern Sierras.

Sierran Chorus Frog (Pseudacris sierrae).
Frogs were in short supply. On most hikes I was lucky to encounter a single chorus frog or toad. Only once did I find a Southern Mountain Yellow-legged Frog (Rana muscosa). As I described in my first article, it was tucked away in a remote high-elevation stream in the San Gabriel Mountains, part of a population down to its last dozen or so frogs. Nowhere else did I even cross the path of a ranid (true frog).

Before the trip I had known this would be a likely result. Southern Mountain Yellow-legged Frogs are basically gone from these elevations. Despite low expectations, I still went through something of a mourning process as we hiked pristine streams and gorgeous meadows yet found nary a frog jumping into the water. My father and I had to content ourselves with several lizard species, salamanders in the wettest spots, and the occasional Mountain Garter Snake.

Mountain Garter Snakes (Thamnophis elegans elegans) are
often associated with Mountain Yellow-legged Frogs, but now
only chorus frogs survive in this snake’s meadow.
When White fishermen first arrived in California, they met an entirely different disappointment - the fishless lakes and streams of the Sierra Nevada. Their response was to introduce trout to the waters. These rainbow and brook trout survived by competing with frogs for food and even eating the tadpoles themselves. At first fish were only introduced to the most accessible lakes, but in the 1950s the Department of Fish and Wildlife began employing helicopters to plant trout in remote waterways. As sport fish thrived, frogs disappeared. By the end of the twentieth century, 90% of Mountain Yellow-legged frog habitat was inundated with predatory trout.

One step forward, two steps back

Dr. Vance Vredenburg was one of many biologists who saw the dots connect between trout and the frog declines. As the habitat was still intact, he suggested that removing trout could allow frogs to recover. In 1996 he chose the 10,000-foot-high Sixty Lakes Basin as a place to test the theory. Though Southern Mountain Yellow-legged Frogs had been extirpated from many trout-filled lakes in the basin, populations remained in the ponds where fish were absent.

Dr. Vredenburg’s research team used gill nets to extract fish from five more of the basin’s lakes. Once the fish were gone, the frogs returned. Even lakes that still contained trout began to harbor frogs so long as they were adjacent to fishless lakes. Similar studies in other basins confirmed the theory. Conservationists excited by the results began to remove fish from high-elevation lakes across the Sierras.

Sixty Lakes Basin became one of the most vibrant Mountain Yellow-legged Frog metapopulations in the Sierras.  

Frogs killed by chytrid in Milestone Basin.
Photo from Voyles et al. "Pathophysiology in Mountain
Yellow-Legged Frogs during a Chytridiomycosis Outbreak".
That is, until August 2004, when a frog-killing fungal disease called chytridiomycosis (chytrid) entered the basin’s waters and spread from one lake to another. Dr. Vredenburg watched disaster unfold in front of him. “When I witnessed the die-off of mountain yellow-legged frogs from this chytrid fungus, I saw literally tens of thousands of dead frogs littering the shorelines of these beautiful pristine lakes.” As published in “Dynamics of an emerging disease drive large-scale amphibian population extinctions”, the fungus eliminated 98% of the yellow-legged frogs in Sixty Lakes Basin. Twenty-seven of its 33 populations were wiped out in the first five years alone. Sister projects in Milestone Basin and Barrett Lakes Basin suffered the same fate.

This story repeated itself across the Sierras, and testing suggests that chytrid had been responsible for previous Mountain Yellow-legged Frog declines. In fact, the disease has become an existential threat to frogs across the globe, famously causing the extinction of Costa Rica’s Golden Toad and dozens of other species.

An epidemic spreads through Sixty Lakes Basin: Green depicts healthy frog lakes, yellow infected frog lakes, and black the lakes where frogs have disappeared.
Figure courtesy of Vance Vredenburg.

Scientists believe that chytrid originated with a non-lethal strain of the fungus native to the Korean peninsula. That strain can exist in local frogs without killing them, but around 100 years ago it mutated into deadly forms that were then spread globally by international trade and the Korean War. Infected amphibians from pet markets now drive its global spread, while wading birds, fishermen, hikers, and even researchers may accidentally move the disease locally to one new waterway after another.

Sierra Nevada Yellow-legged Frogs have disappeared from this
Yosemite meadow, but may be reintroduced if trout are eliminated.
I began with a narrative of trout, and then flipped to fungus. Which one drove the Mountain Yellow-legged Frogs to near-extinction?

It is likely that both are responsible. Trout decimate frog populations, and so does chytrid. The combination is nearly insurmountable. Air pollution, pesticide exposure, and climate change may also weaken the frogs’ resilience. And when development and high-impact recreation have eliminated many connecting populations, the isolated survivors in-between are that much more susceptible to extinction events.

Yosemite Toads will frequent this lake later in the season.
The two Mountain Yellow-legged Frog species, Sierra Nevada Yellow-legged Frog and Southern Mountain Yellow-legged Frog, are not the only Sierran frogs to suffer. The Yosemite Toad (Anaxyrus canorus) has also been listed as an endangered species. Strangely, it is not as susceptible to trout predation nor chytrid infection, so scientists continue to investigate the reasons for its decline. The Foothill Yellow-legged Frog (Rana boylii) has nearly disappeared from the Sierras, only hanging on in a few places in the lower elevations. It was brought down by a mix of dams, habitat fragmentation, and introduced predators. And the California Red-legged Frog (Rana draytonii) has been reduced to a dozen tiny populations spread out here and there in the northern foothills.

Ways forward in a beautiful land

Grizzlies are gone from California, but we saw two brown-phase
Black Bears recently emerged from hibernation.
In the final week we made it up to the northern Sierras. The streams, lakes, waterfalls, meadows, trees, cliffs, everything were gorgeous beyond compare. Yet just as in the southern Sierras, the frogs were gone. Even when I hiked through perfect-looking habitat, such as one beautiful flooded meadow bisected by a stream, I was distressed to see huge trout dashing through the waters. Sierra Nevada Yellow-legged Frogs and Yosemite Toads still have viable populations at 9,000 feet and above, but those lakes were snowed over. Across three days in the northern Sierras, the Sierran Chorus Frog was the only frog species I saw.

My poor luck does not tell the whole story. Scientists have noted that some frogs are developing a degree of resistance to the chytrid fungus. And highly complex mid-elevation meadow systems, those with a combination of streams, ponds, flooded meadow and forest habitat, may result in frog populations more resilient to infection than the isolated high-elevation lakes.

This mid-elevation marsh, photographed from a distance due to its
protected status, supports populations of Sierra Nevada
Yellow-legged Frog and Yosemite Toad.
Unfortunately, recreational impact and trout introductions have left healthy mid-elevation meadow systems in short supply. But a combination of meadow restoration, fish removal, and the development of fungal resistance may one day allow prime habitat to become viable across the Sierra Nevada. In Yosemite Park there has already been a documented increase in mountain yellow-legged frog populations, leading Roland Knapp of UCSB to affirm that, "given sufficient time and the availability of intact habitat, the frogs can recover despite the human-caused challenges they face."

Given the availability of intact habitat.

It is striking that wildlife suffer from human impact even in one of California’s most pristine ecosystems. But while remoteness does not protect the frogs completely, it does allow a pathway to hope. Through all they’ve endured, the habitat is still there, and as long as the habitat is still there the frogs can come back. Reintroductions are in process with several species and have already shown some success. These waterways may one day be filled with frogs again.


Frog diversity at the northern borders

Our time in the Sierras was disappointing, but luck shifted as we made our way north to Shasta. Shasta Lake is a manmade reservoir created in 1945 by the construction of Shasta Dam, which flooded nearly 30,000 acres of Winnemem Wintu homeland and prime wildlife habitat. Thankfully, the unique rock systems of the area support so many rivers and creeks in close proximity that even with the dam, amphibian diversity remains robust.

Arriving at the meandering roads that track the lake’s arms, my father and I soon encountered a Boreal Toad (Bufo boreas boreas) under a rock. Just a couple feet away we lifted another rock to find a Striped Racer (Masticophis lateralis). Nice start!

Foothill Yellow-legged Frog.
We stopped the car at the first likely-looking stream and started hiking. A splash around the bend alerted us to a frog’s presence. Ears pricked, I followed the sound to a secluded pool where a Foothill Yellow-legged Frog floated in the waters. After nearly a week without seeing a ranid, the sighting brought significant joy.

As we made our way from stream to stream, additional searches revealed Shasta Black Salamander (Aneides iecanus), Oregon Ensatina (Ensatina eschscholtzii oregonensis) and Coastal Giant Salamander (Dicamptodon tenebrosus) in good numbers in the sheltered canyons. Forest Alligator Lizard (Elgaria multicarinata multicarinata) and Northwestern Fence Lizard (Sceloporus occidentalis occidentalis) roamed the sunny spots on the side of the road.

Shasta Lake’s limestone outcrops are also home to three species of Shasta Salamander (Hydromantes sp.), ancient cave-lovers found nowhere else on Earth. Shasta Salamanders are at the center of an effort to prevent a planned $1.4 billion expansion of the Shasta Dam, a move that would destroy 3,000 more acres of their habitat and flood much of the Winnemem Wintu’s remaining historic lands.

At night I hiked out of the campground and found Sierran Chorus Frogs calling in numbers from the lake shore. Millipedes meandered across the forest floor and toads hunted on the roads. The quiet darkness rewarded me with a Ringtail sniffing around an abandoned campsite, the first I’d ever encountered in the wild and my most exciting mammal sighting of the trip. Later I spotted it again, this time making its way through the forest understory. The disappointments of the Sierras had disappeared.



Which is not to say that the Shasta system does not have its own concerns. While Foothill Yellow-legged Frogs are more common in Shasta County, the dams have still cut into their numbers. 

My camera couldn’t capture the real-life beauty of this
Shasta Black Salamander. Matt and I found it near
Whiskeytown Lake before the burn.
And California’s worst-ever fire season burned hundreds of thousands of acres just months after I visited. The Carr Fire devastated Whiskeytown Lake, where I had previously found Foothill Yellow-legged Frog and 14 other herp species. Reptiles and amphibians can adapt to normal burns, but the size and intensity of modern fires eradicates entire populations. And because roads, dams, and development leave areas isolated, sometimes there is nothing left to recolonize the spots that were lost.

The joy of finding tailed frogs is that they frequent
the most gorgeous natural landscapes in the Pacific Northwest
One particularly sensitive local resident is the Coast Tailed Frog (Ascaphus truei). Uniquely adapted to clear, cold, fast-flowing waters in old-growth forest, it can’t tolerate logging, road construction, or fires, all of which fill its habitat with sediment. Canopy loss is also a problem for the frogs when the reduction in tree cover leads to an increase in water temperature.

Some distance north of Shasta my father and I embarked on a five-mile hike with the requisite elements – old unlogged forest and fast streams. Underneath a waterfall at the turnaround point I uncovered two Coast Tailed Frogs side-by-side in a rocky pool.

California’s northernmost counties are also home to the Cascades Frog (Rana cascadae), which fills the same montane niche that the Sierra Nevada Yellow-legged Frog holds a bit to the south. A unique population of Cascades Frog is going extinct in the Lassen region of northeastern California, and no one is certain why. Drought, the introduction of trout, pesticide exposure, and disease all may contribute to the problem. The other California population, residing in remote regions of the Trinity Alps and Siskiyou Mountains, is more robust but also in trouble. Cascades Frogs are doing better to the north in Oregon and Washington’s Cascade Mountains, though declines have been noted there as well.

Only a few miles from the tailed frogs’ waterfall, we encountered a lone Cascades Frog at the edge of a woodland pond.


The last stragglers

The Northern Leopard Frog (Lithobates pipens) once lived along California’s eastern border, but is now extirpated from the state. The grassy meadows it frequented were prime targets for ranchers. Their livestock gnawed down the grassland, leading to a drying out of the soil that the leopard frogs couldn’t survive. Development, pesticides, pollution, and the introduction of bullfrogs also played a role.

One of dozens of bullfrogs spotted in one of the last two western
Nevada strongholds for the Northern Leopard Frog.
At the beginning of our trip my friend Matt and I had crossed into western Nevada, where two populations of the species remain. We visited a site where leopard frogs eek out an existence on recovered ranchland. Unfortunately, even that population is inundated with predatory bullfrogs.  A preserve manager described various control methods to us, but the bullfrogs appear resilient to extermination.

At least 20-30 frogs must have jumped from the banks as we walked. Only one or two of the jumpers were leopard frogs, the rest invasive bullfrogs that threaten their existence in Nevada just as they helped wipe them out in California. Naturalists associated with the preserve are attempting to relocate some frogs to new sites where bullfrogs are absent.

Conservationists press on. The Washington Department of Fish and Wildlife has undertaken a Northern Leopard Frog Reintroduction Recovery Project in Washington state. Through habitat enhancement, head-starting, and bullfrog reduction, they hope to bring a robustness to their leopard frog populations so that they avoid the fate of California and Nevada’s frogs.

Such efforts can only succeed where habitat survives. That is the ultimate issue. When habitat persists, frogs may one day recover. When habitat is bulldozed, planted over, dammed, drained, or built upon…what hope is left?

References:

Thomson, Robert C. California Amphibian and Reptile Species of Special Concern. University of California Press. Kindle Edition.

Nafis, Gary. California Herps: A guide to the reptiles and amphibians of California. http://www.californiaherps.com/

“Pesticides and amphibian population declines in California, USA”, paper published in Environmental Toxicology and Chemistryby DW Sparling

“Effects of nonnative fish and habitat characteristics on lentic herpetofauna in Yosemite National Park, USA”, paper published in Biological Conservationby Roland Knapp

“Reversing introduced species effects: Experimental removal of introduced fish leads to rapid recovery of a declining frog”, paper published in Proceedings of the National Academy of the Sciencesby Vance Vredenburg

“Removal of nonnative fish results in population expansion of a declining amphibian (mountain yellow-legged frog, Rana muscosa)”, paper published in Biological Conservationby Knapp, Boliano, and Vredenburg

“Dynamics of an emerging disease drive large-scale amphibian population extinctions”, paper published in Proceedings of the National Academy of the Sciencesby Vredenburg, Knapp, Tunstall and Briggs.

“Recent Asian origin of chytrid fungi causing global amphibian declines”, paper published in Scienceby Simon O’Hanlon et al.

“Ground Zero of Amphibian 'Apocalypse' Finally Found”, article published in National Geographicby Michael Greshko

"Large-scale recovery of an endangered amphibian despite ongoing exposure to multiple stressors”, paper published in Proceedings of the National Academy of the Sciencesby Knapp et al.

“Opportunities and Constraints of Sierra Nevada Meadow Restoration”, a University of San Franciso Master’s Thesis by Allie Sennett

“Preliminary Restoration of Mountain Yellow-legged Frogs Environmental Assessment”, report for the Department of the Interior

“Disease and climate effects on individuals drive post‐reintroduction population dynamics of an endangered amphibian”, paper published in Disease Ecologyby Maxwell Joseph and Roland Knapp

“Tiny salamanders could stand in the way of massive dam raising project”, article published in the Redding Record Searchlightby Damon Arthur

I want to thank Vance Vredenburg for the use of a figure and photo from his research. Quotes from Vredenburg and Knapp were taken from “Scientists try to save this frog species from being wiped out by fungus”, an article by Public Radio International.

Much thanks again to Shanti Mathias for editing the piece and making suggestions.

Saturday, February 9, 2019

The King Cobras of Northeast Thailand — Researching Lives and Threats --- Guest Post ---

Across the globe there is a tendency for people to view snakes in a negative light, a fear born of unfamiliarity. It is difficult to imagine a scenario where snakes are protected from threats, like habitat loss and persecution, without countering innate anti-snake bias. As we learn about snakes, we can present them in more relatable ways.

Questions concerning snakes are bountiful everywhere, but especially in Southeast Asia. Many species across the region have scant natural history information and remain taxonomically ambiguous. Even the most charismatic snake species lack widespread work that would help us understand their populations and threats they face.

We at the Sakaearat Conservation and Snake Education Team (find us on Instagram!) are exploring the lives of snakes (king cobras, green pit vipers, green cat-eyed snakes, Burmese pythons and kraits) with the goal of understanding their habitat and space requirements. The longest running project involves perhaps the best ambassador for Southeast Asian snakes — the king cobra. They are instantly recognizable, strikingly beautiful, and (perhaps surprisingly to some people) infrequently appear in hospital snakebite records. Despite their charisma and wide-distribution, almost all the modern work on the ecology of king cobras has been limited to the western Ghats in India.

We are working in Thailand's northeast province of Nakhon Ratchasima, in the Sakaerat Biosphere Reserve. The reserve presents an opportunity to study king cobras in a number of habitats. The core of the reserve is protected old growth forest and seasonally burnt dry dipterocarp forest. Surrounding the oldest forests are plantations, attempting to restore a larger area to a forested state. Beyond the reforestation area is a mix of agriculture and small villages. Typical crops for the region are rice, sugar cane and corn, often interspersed with orchards. Straight through the middle of agricultural land, and bordering the forest is a four-lane highway connecting the Northeast to Bangkok. This complex landscape of competing interests and land-use is where our king cobras live, and where the team follows their every move.

King cobras are elusive, presenting a myriad of problems when studying them. Because of the difficulty recapturing kings, we turned to radio-telemetry. Kings of sufficient size and health have radio-transmitters implanted, allowing a signal to be detected and followed. Every day the team heads out, into forest, fields and streambeds to record the kings’ locations. 


After years of tracking, we are gaining a glimpse into king cobra life. We have documented the huge areas they span, over 700 ha (~2.7 square miles) for the adult males. While there is some indication that they prefer the safety (or food) of the forest, they are willing to traverse highways and fields, especially while searching for mates. A dangerous habit given how king cobras are one of the most feared snake species in the region. The pattern of tracked king cobra mortalities in unprotected areas suggest that the fear is leading to persecution.

Our inability to use systematic trapping prevents any conclusions on whether the persecution and accidental deaths in unprotected areas are undermining the king cobra population. But the trend of finding dead kings outside the protected area, together with seeing few instances of natural deaths, is worrying.

How do we prevent further king cobra deaths? A larger protected area could be a solution, but this would be costly, unjustly displace people, and does not tackle the underlying cause. From the mortalities we have witnessed, we believe tackling the negative perceptions and fear surrounding king cobras is important. The lack of human envenomations by king cobras can help convince people king cobras are more threatened than threat. Also, efforts to limit the incidental deaths from road mortalities, pollution and wildlife traps are required. Reducing road mortalities will require better crossing systems, but may also be reduced via education if road-users are deliberately targeting snakes. Both pollution and wildlife trapping will require larger scale changes in society’s attitudes, but can be integrated into local education efforts.

Our tracking of king cobras and other snake species, provides the information we need to conserve them in an ever-changing landscape. One pattern is becoming clear for king cobras, conservation cannot stop at the boundary of protected areas. It needs to tackle underlying prejudices against snakes and appreciate the importance of habitat connectivity.

Papers from SCSET on king cobras: 

Marshall, B. M., Strine, C. T., Jones, M. D., Theodorou, A., Amber, E., Waengsothorn, S., … Goode, M. (2018). Hits Close to Home: Repeated Persecution of King Cobras (Ophiophagus hannah) in Northeastern Thailand.Tropical Conservation Science, 11, 194008291881840. https://doi.org/10.1177/1940082918818401

Marshall, B. M., Strine, C. T., Jones, M. D., Artchawakom, T., Silva, I., Suwanwaree, P., & Goode, M. (2018). Space fit for a king: spatial ecology of king cobras (Ophiophagus hannah) in Sakaerat Biosphere Reserve, Northeastern Thailand. Amphibia-Reptilia.https://doi.org/10.1163/15685381-18000008

Strine, C. T., Silva, I., Crane, M., Nadolski, B., Artchawakom, T., Goode, M., & Suwanwaree, P. (2014). Mortality of a wild king cobra, Ophiophagus hannahCantor, 1836 (Serpentes: Elapidae) from Northeast Thailand after ingesting a plastic bag. Asian Herpetological Research, 5(4), 284–286. https://doi.org/10.3724/SP.J.1245.2014.00284




About the author: 

Benjamin Marshall is a researcher at the Suranaree University of Technology, where he focuses on the analysis of radio-telemetry data. Also keen to communicate research, Ben co-hosts a fortnightly Herpetological podcast that looks at recent research findings.

The Sakaerat Conservation and Snake Education Team was set-up by Dr Colin Strine and is currently being led by Doctoral student Max Jones.

Monday, January 21, 2019

Maybe Sparrow

Maybe sparrow you should wait
The hawks alight till morning
You'll never pass beyond the gate
If you don't hear my warning
Notes are hung so effortless
With the rise and fall of sparrow's breast
It's a drowning dive and back to the chorus
La di da di da di da
—Neko Case

            We walked in two expanding arcs, twelve people out on a blonde, grassy slope extending as far as the eye could see in either direction. To the north, the blue horizon outlined the Davis Mountains, named for our country’s second greatest traitor. To the south, dark trees and buildings mark the town of Marfa, West Texas capital of art and pretention. Black grama and other exuberant grasses abound, every few feet another kind, another patch, all with its own version of fruiting structures; some curly, others wispy, some downright spiny and sticking into my socks.  We spread out into a wide circle, like the scientists trying to work out the dimensions of the flying saucer in The Thing From Another World. At its apex we’ve erected a 60 foot long, ten foot high net with fine filament, fine enough to get repeatedly tangled with tumbleweed. 
            Sebastian, a tall, immediately likeable Peruvian, lifts and waves his staff and we begin closing the circle, walking deliberately toward the net. It takes a few minutes, each volunteer walking, waving their sticks, tapping them on the ground and through the grass. Birds flush and we stop. A single bird rising in a chaotic flutter, making a characteristic twittering, is a chestnut-collared longspur, on winter vacation from the bleak prairies of North Dakota. Fatter birds rising together, wheeling, peeping, are horned larks. We continue. A single bird flies a low trajectory parallel with the grass. 
            “Bird!” Denis calls out. We stop. We track its flight across 50 yards, it dips, lands in the grass. “Down!” she says. We continue. We flush about five more birds until we cinch the circle to the size of a backyard basketball court. 
            “Ok, let’s go slow everyone!” Sebastian calls.  “Everyone! I can see the birds.”
            I’m standing next to him, so I look down. In the mixed gravel-dirt and grasses, a lizard scuttles across the dirt. But it’s December, and just above freezing. It was no lizard.
            “Let’s flush them one at time into the net,” he directs, “Really slow, one at a time. Listos.” The volunteers are a mix of gringos who speak only English, Mexican Americans who speak Spanish and English, Mexican students from Chihuahua who speak Spanish and English, and the principal investigator, a blonde woman named Mieke Titulaer who lives in Mexico and is teaching her newborn to speak Spanish, English, and Dutch. The commands switch idiosyncratically from English to Spanish and sometimes I can’t tell what’s going on. We walk forward.
            A little brown bird—a little brown job—bursts from the grass, flies like a grasshopper and careens toward the net. Fabiola and Denis toss Frisbees. The bird ducks the soft toys, plows into the net. Denis runs out and gathers the bird from the filament, bags it. We walk forward. Another bird flushes and is captured by Fabiola. We continue.
            A bird flushes and heads away from the net. Everyone yells “Bird!” It’s heading my way. I raise my sticks and Kimberly, a student from Chihuahua, starts doing jumping jacks. The bird dives down between us. We take a few steps back and then move toward the clump of prickly pear cactus where it dropped. The cactus grows from a raised mound of gravel and dirt with large holes—the characteristic burrows of a banner-tailed kangaroo rat, the largest rodent of its kind in the area, a white-tipped, cheek-pouched, big-footed creature and indicator of excellent grasslands. We search for the bird, beating with our sticks, and I start to wonder if it actually went down a burrow. Then the bird darts out of the clump, runs like a mouse, we chase it. It flies low and away behind us. A miss. We continue.
            The circle is the size of a small house. We know there are at least three more birds in front. Then one, two, five birds are up at the same time, and then the net has seven dangling little birds. There is a melee as all volunteers with bird handling experience try to get them all secured. Now thisis the kind of birding I can get in to. This wasn’t your typical, coward’s birding, standing freezing your ass off at six in the morning in the cold, walking around with a bunch of nerds glassing a sapsucker on a tree. This was running around, chasing things.  Flushing, beating, flanking. This was heroic birding. This was like herping.
Five minutes later we’re back at the vehicles, and eclectic cloth bird bags are bouncing from a line tied across the back door of the SUV. Fabiola and Denis break out the equipment. The birds will be measured, weighed, banded, and some will get a tiny backpack tied between their wings that will tell Fabiola where they go from now until March.
I was out helping Fabiola with her research project, part of a trans-national effort to study the ecology of rare birds intimately tied to grasslands. Incorporating researchers and volunteers from Mexico, the United States, and Canada, it is an ambitious project, standardizing effort and methods across an enormous swath of North America, from Chihuahua and Durango to west Texas, from Colorado and Montana to Alberta and Manitoba. Formerly, a suite of birds ranged throughout that vast region, and the grassland stretched unbroken from the windswept foot of the northern Rockies to the honey-colored plains of the Mexican Plateau. Short-eared owls, burrowing owls, ferruginous hawks, Swainson’s hawks, northern harriers, prairie falcons, aplomado falcons, horned larks, larkspurs, pipits, and a dozen kinds of sparrows occupied the grassland. The Dixon Water Foundation property north of Marfa, where we now captured birds, has been visited by all of them. 
    The most highly coveted, from a birder’s perspective, is a sparrow. Two of the volunteers were on a birding tour of Texas and volunteered today so they could see it. They stood around at lunchtime talking about birds they recently “had”—that peculiar figure of speech birders use, as if seeing a bird was the same thing as ordering a Rueben sandwich. The reason the bird is so highly regarded has nothing to do with its attractiveness, although, for a sparrow it is quite dapper. And it may not be all that rare. It’s just hard to “have.” You could walk these grasslands all day, where there are probably hundreds, and never see it. Or you might catch a glimpse but there would be no way to confirm it. They don’t tend to perch or flush. They prefer running along the ground like a mouse. They belong to a group of grass-running sparrows—along with Henslow’s, LeConte’s, Botteri’s, and Nelson’s, all of which are coincidentally named after people—that are maddeningly difficult to get a good look at. And we had them in hand. They have the typical tabby-patterned back of most sparrows, but with a handsome, tan face, and thick black streaks contrasting with a plain white chest and belly. Its song is a sweet up and down whistle, quiet and nearly the pitch of an insect, followed by a pleasant downward trill. Itwas named for Spencer Fullerton Baird, the 19th century Smithsonian curator and, namesake also for a sandpiper, tapir, and ratsnake. 
Baird’s sparrows winter in shortgrass prairie and desert grasslands from Durango and Chihuahua to west Texas and southern Arizona, and around March they at last lift themselves from the ground to fly direct to their breeding range in shortgrass prairies of Montana, North Dakota, Manitoba, and Alberta. They take part in that peculiar shell game of migratory birds. When they leave the Marfa area, these same grasslands, now apparently unfit for their use, are happily occupied by Cassin’s sparrows, which use them for breeding. Likewise, the breeding range of Baird’s sparrows, which becomes a snowfield in winter, is perfectly suitable for wintering American tree sparrows, which arrive from breeding grounds further north.
All of these grassland birds were formerly much more common. Fabiola wanted to determine their ecological requirements, especially their overwintering biology, and to understand what is contributing to their decline. Baird’s sparrows have experienced a 77% decline since 1966. 
Fabiola and I talked about this while moving the nets after capturing several Baird’s and grasshopper sparrows, which have also declined significantly in recent decades. 
“You say you’re studying the birds to understand their requirements, when I think we know why they’re declining.”
“Yes,” she agreed, “They don’t have any place to go. It’s like everything else. They can’t survive if you let a grassland turn into a creosote flat. They can’t survive if you turn a grassland into center-pivot agriculture.”
Fire suppression and overgrazing has led to shrub encroachment, turning formerly diverse desert grasslands like those near Marfa into shrub deserts like the sea of creosote and mesquite up near Ft. Stockton and Midland. Unsustainable irrigation—the mining of fossil aquifers—has destroyed more of the bird’s wintering and breeding habitat. Birds are now restricted to tiny remnants of a once vast ecosystem that included grass-running sparrows, banner-tailed kangaroo rats, black-tailed prairie dogs, prairie rattlesnakes, massasaugas, horned lizards, pronghorn, and bison. 
In small reserves, and on forgotten, neglected ranches, prairie remnants remain. The Janos grassland in Chihuahua, where members of the team join Mexican collaborators for training, has almost the entire cast of characters, including bison, and was recently the location of the first black-footed ferret reintroduction in Mexico. The grasslands in west Texas are missing bison for the most part, could use more prairie dogs, and would welcome the arrival of ferrets. Ranchers opposed a recent effort to reintroduce the ferret on a private ranch in the Texas Panhandle—you might say that the position was hypocritical, given the usual stance of Texas ranchers regarding the rights of private landowners. 
The grasslands and their birds, mammals, and reptiles will therefore remain fragmented, degraded, incomplete, declining, and fought over, for the foreseeable future. 
Maybe one day we’ll integrate grassland management on a large scale, and these early trans-national research projects will be remembered as the obvious template for cooperation. Ranchers will trade their cows for bison, prairie dogs will lose their nuisance mystique (show me evidence cows step in their holes and injured themselves), ferrets and wolves will return, barbed wire fences will fall, and fire will be thought of as a management tool instead of disaster. The Janos grassland in Chihuahua will be linked by an archipelago of restored shrublands to the Marfa and Marathon grasslands in Texas, with free movement allowed between.  Maybe sparrows will return.
But for now we had more birds to catch. We walked out into the diverse grassland, on to the next circle. 

Sunday, January 13, 2019

On the Border with Black Bears

 By Sean Graham       

      The sun was going down so I hustled back up the trail to avoid hiking out at night. Walls of yellowish-pink igneous rock stood vertical on either side of the trail, thickets of shrubby vegetation lined the arroyo leading up a couple of miles to Casa Grande, the picturesque mesa of Big Bend National Park. I passed an older man heading back up the trail, and he said something like, “You’re really pushing it!” I hiked this trail every weekend, doing standardized surveys, and people always wanted to know what I was doing holding a notebook, and many mistook me for a park ranger. After the hike down, I was free to put on the afterburners and “push it” on the return hike. I rounded a corner with a blind spot behind it, like entering a room in a strange house.
            A loud grunting stopped me in my tracks. I looked up from the trail and saw a small bear standing in the middle of the trail, his nose snorting. The hair on his back went up, he wheeled, and I watched him haul his cute little ass across the arroyo. The whole thing lasted no longer than a second and startled me witless. I continued up the trail, watching the little bear scramble halfway up a brushy hill. 
            Then I saw mama.
            A large female bear was down in the arroyo fifty feet away. She was sniffing the air, looking agitated. I walked backwards the other way, up the trail, talking softly to her. 
            “It’s ok mama. You’re a good mama bear. I didn’t do anything. I’m walking away.” I walked up the trail and was about to turn around and resume my earlier pace and get the hell out of there when I thought about the heavy-set man behind me. I just spooked a baby bear and managed to separate it from its mother. If the man walked right into mama, things could get bad. I stood next to a large boulder and waited. I watched her continue searching for her youngster, sniffing the air. Looking at me, sniffing my way. The baby climbed up to the ridgeline. The man appeared and rounded the corner. I got his attention, and waved him over, silently. 
            “Look.”
            “Oh goodness a bear!”
            I explained what happened and we admired the bears for a minute. Then I shook his hand and walked back to my car. 
            I’m a big fan of bears, and not just because they’re cute and charismatic, and not because of all of their ecological benefits. It’s because they’re potentially dangerous. It’s because of their swagger. Having to change your plans because of the presence of another, much larger animal that can kill you is one of the great things about places like Big Bend. It wouldn’t be the same without them.
            By the 1940s and the establishment of Big Bend National Park in Texas, black bears were largely extinct in the state. Bears, along with wolves, were poisoned, trapped, and shot out; the same old story for most of our large, potentially dangerous mammalian carnivores.
            Then in 1985, a bear was seen in the park, and sightings increased year by year, so that by the time I first visited Big Bend ten years later, they were reestablished. The origin of these bears was out across miles of desert flats, across the winding, grey-watered Rio Grande, out past the desert cliffs, up in the mountains of Mexico. 
Bears, like many mammals, have an instinctual tendency to leave their parent’s territory when they approach maturity. This is encouraged by the mother, who, after lovingly nurturing their young for months, essentially kick them out of the house. Juvenile mammals wander until they find vacant habitat. I saw a young bear wandering in the desert—in the bare, low creosote out near Terlingua, Texas. Out looking for greener pastures. 
This repopulation is happening all over the country due to species protection and the declining popularity of hunting: jaguars, mountain lions, wolverines, fishers, and wolves are all rebuilding their numbers and juveniles are dispersing, reoccupied territory where they have not been seen in decades.
Progress reestablishing many wildlife populations relies on natural dispersal and connectivity between the U.S. and Mexico. A wall erected as a political ploy will block their way.

                                                                      ****

 We arrived at the headquarters of the CEMEX El Carmen office in northern Mexico after a 12 hour drive. CEMEX is the largest cement corporation in the world, and offsets its environmental impacts with proactive conservation programs. The El Carmen Project is its crown jewel: the company purchased, restored, and protects a 208,381 hectare preserve across the river from Big Bend. Together with adjacent preserves in Mexico and Texas, the region represents one of the largest protected areas in the world. We have the privilege of surveying the preserve for amphibians and reptiles.
We turned in at the bunkhouse. In the middle of the night my colleague Tomas woke us up.
“Guys, it’s a bear!”
Tomas was jealous of all my recent bear sightings. He had never seen one.
Now a large black bear was rummaging through our stuff in the bed of my truck. We had brought all our food indoors, but realized we left out a few granola bars. We opened a window and hissed at it, yelled at it, swore at it.  It dropped from the truck without a sound—remarkably stealthy for such a big animal—and walked away. Ten minutes later, it was back. We shooed it away again, and went out with headlamps to bring in the rest of our stuff. Dogs started barking. The bear didn’t return. 
Tomas had a very unusual first-bear experience. The bears of the Chisos Mountains are remarkably well behaved, and not a single bear-human mishap has occurred since their return in 1985. The park established a network of bear-proof boxes throughout the park, including at remote backcountry sites, and does a great job of educating the public, preventing nuisance bears. 
  We saw several more bears that week, including seven in one afternoon driving across the grassy foothills of the Carmens. We searched an oak canyon, finding small lizards perched on the rocky cliffs, where black-capped vireos—an endangered species in the U.S.—were common and twittered nervously, about one every hundred yards. A big commotion, crashing in the brush, an amorphous black shape in the shadows. A huge fresh turd in the wash where the commotion began. 
We were having good luck, searching canyons by day, driving roads by night, and found many rare snakes, representing new records for Mexico. We tended to celebrate after days like this. And celebrating in Mexico means endless Tecates and copious tequila.
 I was in and out of a swirling, syrupy sleep. An incredible racket woke me. I assumed it was the wind slamming shut the front door. It went on smashing like that for a minute, but I didn’t want to get up. I didn’t know if I could get up. My spinning head came to life, focused on the sound. It was more of a wrenching sound. I thought somebody was screwing around trying to get one of the windows closed. But it went on for another full minute. I was right about to get up and start yelling when I heard Tomas.
“It’s a bear!”
“What the hell?” I called out. My brain wasn’t working right, but now a small dollop of fear dripped into my inebriated delirium.
I stumbled into the kitchen. Tomas was standing there looking at the window near the sink. The sound was incredible. It sounded like a linebacker trying to push a car door open the wrong way. Like the raucous squawking of a pterosaur. Like a piston at an industrial plant. Like an enormous bear trying to tear its way into a house. 
All the windows and doors were reinforced with metal latticework. The bear was attempting to rip open a weak spot to get inside. Tomas started hissing, yelling at the bear. 
It looked like he had everything under control, and I could barely stand up, so I crashed out again. 
The wrenching sound came back 30 minutes later. El Oso Negro had returned. After more shooing and shouting, he finally went away.
Black bears are extremely common in the Carmens, possibly exhibiting higher population densities here than any other place in North America. Bears can be active year-round in the Carmens because of the many kinds of oaks; a good mast of acorns is always coming into season. Given their densities here, it’s obvious how the black bear returned to Texas. 
And more are on the way. 
You may wonder why I would mention a story of marauding bears in Mexico crossing the border into Texas. Isn’t this just more fodder for those who favor a strong border, and a big, beautiful wall? What kind of argument is this? Well, anyone who would use this as an exemplar for border security would only be using senseless fearmongering. The chances of a black bear attacking you are vanishingly small, even when ornery and habituated to humans. Anyone who is more scared of bears than getting into car accidents or getting gunned down by their fellow Americans has clearly succumbed to irrationality. Anyone who doesn’t respect the beauty and courage of these bears, who cross dozens of miles of inhospitable desert to find a better place to live, doesn’t have enough measurable empathy and humanity. The bears enrich our local flora and fauna and contribute to biological productivity. And, there’s the economic incentive: bears consistently top the list of things national park visitors want to see, and the parks are an enormous economic boon for nearby rural towns. Big Bend is a classic example, and the migrant black bears a case in point. 
You might recognize some parallels between the bears and other timely issues. I stand by the metaphor.