Tracing Gold: Disappearing Eagles in the West Desert
Thursday , August 28, 2014 - 12:19 PM
Eric Chabot and Dave Buchanan stand on the edge of a cliff in a barren corner of the West Desert. Already, they’ve run into a snag. The original idea was for Chabot and Buchanan to rappel off the top, stop half-way down, grab a pair of angry golden eagles out of their cliff face nest, coax the birds into large bags while avoiding flailing two-inch talons, then rappel the rest of the way with the bag o’ bird to a temporary lab site in the boulder field below. But that isn’t going to work.
Chabot and Buchanan are field technicians with HawkWatch International. Their trip to one Utah’s most remote stretches is part of a research project to track golden eagles and find out why one of the living symbols of the desert is disappearing.
But on top of the cliff, there isn’t anything sturdy enough for an anchor. There is nothing but small shrubs, grass and football-sized boulders.
After double-checking their options, they decide to tie the rope to a rock small enough to pick up with one hand. They then bury the anchor with enough debris to counter the weight of a free-hanging climber. Twenty minutes later, Chabot pulls against the cloth webbing that snakes out from under the three-foot tall stack of rocks and the tower holds still.
Well, the tower holds fairly still.
For an extra bit of security, Buchanan agrees to sit on the tower as Chabot rappels solo down to the nest.
Chabot throws his rope off the cliff, and moments later he is suspended in the mid-day sun. Fifteen feet down, he stops at a shallow hole in the cliff face where two juvenile golden eagles stare out at him. While only seven weeks old, the birds are already over seven pounds each and not thrilled with the visitor.
With long leather gloves, Chabot reaches for the closest eagle and hugs it to his chest as he slips a falconing hood over the bird’s head.
Leaning back on his rope, Chabot yells back to his coworker and safety weight.
“This other one’s not too psyched that I’m here,” calls Chabot. “He might try to jump.”
At this age, the birds haven’t fledged yet, meaning they aren’t able to fly. If the bird jumps, it could get injured in the fall or lost in the boulder field below.
With only enough gear for one bird, Chabot clings to the hooded eagle and takes the bag he was going to use and spreads it over the second bird. Under the dark of the bag, eagle No. 2 will stay calm until Buchanan can reach the nest. With his right hand on the rope, and a massive coffee-colored eagle tucked under his left arm, Chabot begins his final descent.
In 2009, HawkWatch, a conservation focused non-profit based out of Salt Lake City, and the Department of Defense were looking at nesting raptors in the West Desert and questioning why the numbers of the birds were going down.
Despite their position at the top of the food chain, there is no shortage of threats to the golden eagle.
“Lately we’ve had eagles colliding with wind turbines,” said Steve Slater, conservation science director for HawkWatch International and the leader of the golden eagle project. “We have unsafe powerline poles where they can get electrocuted. In the winter time they can go along roadsides and feed on winter deer kills that have been hit by vehicles, and once they’ve fed, they can get into trouble because they have a hard time getting off the ground and get hit by the next car.”
For Slater and the other biologists on the project, the work comes down to one major question.
“Specifically,” Slater said, “what threats are they facing that are man-made that we can hopefully help correct based on the data that we get back?”
From the start of the research project, there has always been one threat that topped all others: cheatgrass.
In other words, a bird with a seven-foot wingspan and the talon strength to take down a deer is being defeated by those annoying little seeds that poke in your socks when you walk through the desert.
“It is bad,” Eugene Schupp said. “It is one of the biggest challenges we face in managing lands in the western U.S.”
Schupp is an ecology professor at Utah State University who studies landscapes decimated by cheatgrass.
“Some people have given up hope,” Schupp said. “There are people who advocate to just live with it. I’ve always been a fairly optimistic person so I don’t give up and there are many of us who don’t give up.”
Cheatgrass first showed up in Utah in the late 1800s. The invasive grass is native to Eurasia and was unintentionally brought to the United States with livestock feed. In the shrublands and sagebrush steppes of the west, the grass took root where native plants were beaten down by livestock.
Unlike the native grasses, cheatgrass dries out very early in the summer and creates a long, extended fire season.
“If we don’t have a very good dense strong understory,” Schupp said, “It frees up a lot of resources for cheatgrass to come in and cheatgrass promotes more fire, and more fire, and more fire. With added fire it starts killing off even those grasses that survived the first fire.”
Ecosystems that once saw fire every 30 to 100 years are now experiencing multiple fires each decade. In the end, what once was a landscape with a rich mixture of shrubs, sage and grasses, is now a field of dried up purple cheatgrass, which doesn’t bode well for eagles’ primary food source.
Golden eagles will eat a wide variety of mid-sized animals, but their main entree in Utah is jackrabbit. Unlike some species of rabbits, jackrabbits don’t dig a burrow, but instead depend on shrubs for shelter.
When the cheatgrass comes in, the fire comes in. When the fire comes in, the shrubs die off. When the shrubs die-off, the jackrabbits are gone. And when the jackrabbits are gone, the golden eagles starve.
These connections from the eagle to the grass means that researchers looking at raptors are actually looking at a whole lot more than a couple dozen birds.
“We focus on birds of prey in general as indicators of what happening on the landscape.” Slater said. ”They are dependent on really large landscape and it takes really large landscape changes for them to start to suffer ... they really do some kind of the sampling of the environment for us.”
Scientists refer to this as an “indicator species.” The well-being of certain species can indicate how healthy the ecosystem is as a whole.
Bird in Hand
When Eric Chabot and Dave Buchanan reach the ground, the real work with the eagles begins. Steve Slater and fellow HawkWatch biologist Shawn Hawks join the rappellers to examine the birds.
One person works to contain the wings and talons while the others attach an ankle tag and measure the bird’s size and weight.
The glamour of holding a wild eagle is counteracted with the smell of defecation and half-eaten rabbit parts that the birds had been nesting in for weeks.
Each young eagle weighs in at around 3.5 kilograms, or just under eight pounds. The year before, few of the 19 eagles caught were above 3 kilograms. This increase in weight goes along with an increase in the number of rabbits that the biologists have observed.
“This year, we had a little bit of a bump up,” Slater said. “Not like what we’d like to see historically with just a bumper crop year for jackrabbits, but it has been a warmer spring and there’s been more rabbits out here that we’ve been flushing.”
When the measurements are complete, each eagle is fitted with a small GPS unit. With the help of a makeshift backpack, biologists attached the thumb-sized solar-powered device between the eagle’s wings.
With the measurements complete, Chabot holds the bird to the sky and the eagle flaps its massive wings. Biologists perform this check to make sure that the transmitter won’t limit the bird’s movement.
These eagles will be living on their own in a matter of weeks, and when they’re five-years-old they will begin raising young of their own. The nesting habits of golden eagles are fairly well understood by scientists, but little is know about those years in between.
“This first three, four years of their life is a real risky period where they get into a lot of trouble.” Slater said. “Just leaving the nest, the story’s not over for them.”
Slater and his colleagues hope to find out what is happening to the eagles in that adolescent dark zone. The transmitters record 14 points a day, giving biologists a picture of where the birds are as they move around North America and what kind of trouble they may be getting into. If any of the eagles die with the transmitter running, Slater and his team can track down the bird and figure out if it died from natural causes, power lines, automobiles, changing environments or any number of other challenges.
“I still get nervous every time I download the data,” Slater said.
He recalls the story of one eagle that he tracked as it moved through Idaho. Each time he looked at the data, the bird’s path got closer and closer to a clump of wind turbines visible on Google Earth. At the last moment, the eagle turned south and avoided danger.
Not all birds are so lucky.
Back in the Nest
With transmitters attached, Chabot climbs to the top of the cliff to return the birds to their nest. The rest of the crew packs up and makes their way back across the desert. They’ll be driving to Nevada and working their way south to more nest sites.
In the shade of the nest, the solar transmitters power off, but they’ll turn on when the young eagles take their first flight over the shrubs, salt flats and cheatgrass below.
Weeks later, the transmitters came online, and Slater went to his computer to check the first movements. One signal showed an eagle exploring the hills around its desert home.
The second signal was 300 meters from the nest and not moving. Someone went back out to pick up the stationary transmitter.
“We don’t really know what happened,” Slater said. “It was just feathers at that point.”
Of the 24 eagles that HawkWatch worked with this summer, three of the birds didn’t make it.
Biologists have to take the bad with the good. Each year some birds don’t make it and the long list of threats to the golden eagle is still there.
However, in recent years, the golden eagle has been added to the Utah state list of sensitive species and HawkWatch has helped form a Utah eagle working group with other non-profit, federal and state agencies.
“All of these people are meeting to talk about eagle issues and what we can do,” Slater said.
For Eugene Schupp, the tidal wave of cheatgrass and the changing desert ecosystem remains a struggle, but not one without hope.
“I do like a challenge. I like solving puzzles, and this is an ecological puzzle,” Schupp said. “I don’t think it does anybody any good to be pessimistic….I might be dead before its figured out, but I think we can solve it.”