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OUTSIDE PINEDALE – Josh Hemenway sat in the frigid dark of the southwest Wyoming prairie hoping to witness something few people had ever seen.

The odds were not in his favor. Sage grouse, the object of his query, spook easily and are unpredictable. Hemenway wore dark clothes and crouched low to the ground. The chicken-sized birds are wary of anything tall.

Coyotes howled and yelped in the distance, phantom sounds carrying through the darkness. A bird rustled to the left.

Another faint sound, possibly clucking, came from somewhere closer.

The patch of dirt where Hemenway trained his binoculars was empty as the sun crested the horizon over the Wind River Range. Clouds changed from grays to pinks and oranges and then to white. Still he waited.

That’s the problem with trying to witness a strange phenomenon. It is by definition hard to find.

What made the biologist keep his chilly vigil?

The chance to see sage grouse eating dirt. Very specific dirt.

Such specific dirt, in fact, the birds seem to flock from miles away to peck at golf ball-sized holes in the ground. It is a pilgrimage of sorts, a daily or weekly journey hundreds of birds follow for reasons no one understands.

Hemenway and his fellow biologist at the Bureau of Land Management’s Pinedale office discovered the ritual two years ago and have been trying to decipher its significance ever since.

Because while the journey itself may interesting to only the geekiest of wildlife biologists, the implications could have much broader appeal. Government, nonprofit and industrial groups have spent many millions of dollars working to conserve sage grouse in the West.

A key to that goal, the biologists argue, is better understanding the grouse themselves.


Hemenway and fellow BLM biologist, Dale Woolwine, stumbled on evidence of dirt eating while driving fence lines looking for dead birds. Sage grouse spend most of their lives on the high plains sage brush steppe, where the tallest point on the landscape is an old bush or rock. They’re not used to fences, wires or poles.

“They don’t fly really high,” Hemenway said. “They don’t see the wires. When they hit, they’re gruesome incidents.”

To prevent some collisions, the two biologists hang reflectors on the wires.

Near one particularly lethal section of barbed wire about 20 miles southeast of Pinedale, the biologists found a snowy area pounded down by hundreds of sage grouse tracks. In the middle of the tracks were small holes – no bigger than golf balls and no deeper than a few inches – that had been pecked into the earth.

Several miles down the fence line, another site appeared.

The biologists saw hundreds, if not thousands, of grouse tracks, droppings and a handful of holes dug into the ground. It looked like the remnants of a drunken, early-morning party – the partiers nowhere to be found.

“When we found the second site in the same day, we thought, ‘What the hell is going on?’” Woolwine said.

They found only one passing reference to dirt eating – or geophagy -- in scientific literature from a 1950s, Wyoming Game and Fish-funded study. But another biologist in the Jackson area reported seeing something similar on the National Elk Refuge years before.

It was strange enough to at least look for more sites, the biologists figured. During the next two years, they searched the desert and set camera traps to video the events.

Not only did they find others, they documented more than 20 similar sites in the prairie outside Pinedale.


Camera traps and video footage show the same pattern at each site. Birds arrive between 7 and 7:30 a.m. and usually leave by 10 a.m. from mid-November through February.

The birds don’t court each other with flamboyant displays of feathers and sound like they do in the spring mating season. These encounters are reserved for only one thing: dirt eating.

With every bit of information the biologists learn, they find more questions.

The dirt eating sites are all in low places with disturbances to the ground such as roads, edges of old reservoirs and eroded drainages. Very preliminary soil test results show the holes might contain slightly elevated levels of sodium, but both Hemenway and Woolwine are quick to say the results are early and far from conclusive.

What scientists don’t know is much more extensive.

Where are the birds coming from? How often to the same ones appear on a site? Do they only arrive in the winter? What do they do with the dirt? Because, unlike other birds, sage grouse don’t have gizzards that require gravel for digestion.

The exposed areas make the earth-colored birds more susceptible to predators. What could they need so badly to risk death?

To begin answering the questions, Woolwine and Hemenway began working with other sage grouse biologists and conservation groups. Looped into the study, one way or another, are Wyoming Wildlife Consultants, Sublette County Conservation District and the U.S. Forest Service.

Biologists are trapping sage grouse and attaching a kind of GPS fanny pack to the birds to track their movements.

All of this comes at a time when sage grouse are at the center of a multi-state controversy. The U.S. Fish and Wildlife Service has said it will decide by the end of September whether sage grouse deserve a spot on the endangered species list. A rider in a recent national budget bill forbids the service from spending money on a ruling this year should it decide to list the bird.

But that only delays the inevitable, says sage grouse advocates. Listing the birds could have serious impacts on Wyoming’s energy and agricultural industries.

In the meantime, Gov. Matt Mead recently announced a five-year reassessment of his sage grouse policies. BLM agencies are in the midst of preparing their resource management plans.

The more people know, the better they can prepare, Hemenway said.

“If we find these spots, we can ask, ‘How do we manage for these locations?’ Do we want to put a gravel pit on top of one when we know 100 birds use it regularly in the winter time? Maybe not,” Hemenway said. “Let’s move things around and get some kind of buffer in there.”

Sage grouse numbers in southwest Wyoming and across the state are trending up right now, said Tom Christiansen, Game and Fish’s sage grouse coordinator. Last year’s wet spring increased survival for adults and chicks.

Dirt eating is interesting, Christiansen said, and biologists should try to better understand the phenomenon. But he cautions placing too much importance on it before it has been thoroughly researched.

Woolwine and Hemenway agree.

It took more than a decade to arrive at the current science protecting the areas where sage grouse mate, Woolwine said. If this turns out to be something critical to sage grouse, it will take many more years of study.


Back in the desert, the clucking grew louder. One male grouse appeared silhouetted on the hill.

Hemenway waited in the same place by the fence where he and Woolwine realized they found something interesting years before. Since then, the men had never seen the ritual. They had only watched videos before this early February morning.

As doubts the birds would appear grew, a flock swooped in from the west and landed near the site.

“They’re coming,” Hemenway whispered, hunching forward, binoculars pressed to his eyes.

Another group came from the east, and another from the south. Most landed around the area in the sage brush, then walked slowly to a spot no larger than a hotel room.

As Hemenway crept closer, three more grouse whipped by his head.

Just as the videos showed, the birds puffed and jostled, focused only on pecking at the small holes. Dozens gathered at a time. About 70 joined before they began scattering once again.

Coyotes continued howling their deadly reminder.

And as suddenly as the grouse appeared, they left. In their wake remained a matted down patch of snow and mud with four little holes dug into the dirt.

As Hemenway and other biologists search for reasons why, they hope to fill gaps in knowledge that could potentially be critical to the bird, and to Wyoming’s future.

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Reach Assistant Content Director Christine Peterson at 307-746-3121 or Follow her on Twitter @PetersonOutside.




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