BLACKTAIL POND — In a sagebrush-dotted field not far from where a grizzly bear fed on a bison carcass only two weeks earlier, Dave Haines settled in behind a spotting scope pointed at the forested hillside to the north.
“Blacktail has two tree nests and a great ground squirrel population — probably the best in the park,” he said without glancing up.
The tree nests he referred to were made by golden eagles, a raptor whose presence in Yellowstone National Park went unstudied until the creation of the Yellowstone Raptor Initiative in 2011 (see related story on A1). The big birds — which can weigh up to 14 pounds, measure almost 3 feet long with a wingspan of more than 6 feet — don’t usually nest in trees. They prefer cliffs with expansive views overlooking their hunting area. But it appears that in Yellowstone, at least, the birds are willing to make exceptions when the conditions warrant.
Spotting raptors nesting in trees is no easy task.
“The hours these guys put in, if it wasn’t for them we wouldn’t know the eagles were here,” said Doug Smith, Yellowstone’s senior wildlife biologist, in praising the work of Haines and others involved in the study.
Although the birds have never been tagged for tracking, their nests have been screened for important data.
“I pulled seven to eight marmot skulls out of this nest,” Haines said. “Three out of five years they’ve fledged chicks. It’s probably the most productive golden eagle area.”
Smith, who was straining to see this year’s eaglets in the tree canopy, could only shake his head at the encyclopedic knowledge Haines was carrying around in his bushy-haired head.
“In case you haven’t noticed, Dave is a raptorholic,” Smith joked.
The 39-year-old Haines admits to being a bit obsessive at times about the variety of birds that he’s studied — everything from peregrine falcons to ravens. Golden eagles are his latest passion.
“When you’re at the top of the food chain, there’s a lot going on,” he said.
His fixation has also been driven by the people involved in the work. He first got engrossed with the reintroduction of peregrine falcons after they had been listed as an endangered species following a large die-off thanks to human use of the pesticide DDT, which thinned the birds’ eggshells.
“I was influenced by heroes who were faced with a species in peril (peregrine falcon) and went above and beyond to participate in one of the few wildlife success stories,” he wrote in an email. “I stand on their shoulders and never forget the opportunities they have given me. Basically they were cool dudes who I wanted to be like.”
Now Haines is considered one of the “best golden eagle catchers” around, according to Smith.
As a species, golden eagles haven’t received near the attention of bald eagles, possibly because the bald eagle was adopted as a symbol for America. Thanks to the banning of DDT, bald eagles — like peregrines — have made a strong comeback after severe declines that left them on the edge of extinction. Smith said bald eagles are now so numerous in Yellowstone National Park that they’ve become a predator on the young of some fragile bird species, including trumpeter swans and the largest isolated loon population in the Northwest.
Unlike their cousins, golden eagles are more often associated with the desert, grasslands or tundra regions — none of which Yellowstone has. So their presence in the park has become an area of great interest to researchers like Haines, Smith and others.
“I think it’s safe to say they are associated with rocky dry habitats,” Smith said. With palms up he gestured to the surrounding landscape of snowcapped and forested mountains and noted, “This isn’t that. It just doesn’t fit.”
Which may explain why a pair of goldens that occupy a “flagship golden eagle territory” in the northeast corner of the park seem to have a hard time reproducing, despite all of the nest building and courtship behavior Haines has observed. Usually a mating pair will have several nests in its territories. Nest building is part of the pair’s bonding process.
“I feel comfortable calling this a nonbreeding territory this year,” Haines said.
Until this small cadre of scientists sought funding to study raptors, there was little baseline data in the park, although osprey, bald eagles and peregrine falcons were studied. Smith noted that one of the first and few recorded sightings of a golden eagle in Yellowstone was made by former President Theodore Roosevelt.
During a 1903 visit to the park, Roosevelt wrote to his friend and fellow conservationist Dr. C. Hart Merriam that he had seen a golden eagle attack a band of elk driving them “in their fright” toward him.
“It separated a weak yearling from the herd and then hovered around his head — almost striking at it but evidently unable to quite make up its mind to the attack; finally it left and flew away,” Roosevelt wrote.
In general, Haines said flying is so energy consumptive that golden eagles will wait for ideal conditions before launching to ensure they don’t have to flap a lot.
“On the right day they can fly for two hours and not flap once,” he said.
With spotting scopes set up within view of a park road, it was a given that tourists would soon stop at the spot to see what the raptor crew was looking at through their large spotting scopes — a grizzly bear or possibly a wolf?
“I say birdwatching and they almost always leave,” Smith said. “One out of 20 will be a birdwatcher.”
“Most won’t even get out of the car,” Haines said. “They just drive off.”
But for Haines the pull of the graceful airborne predators is as strong as a summer afternoon updraft.
“Every now and then you’ll show people a nest with chicks and it’s a jaw-dropping experience,” he said.
Certainly for Smith and Haines golden eagles are topflight.
“You talk about iconic bird species, golden eagles are it,” Smith said. “It’s that mystery. They’re not as visible as bald eagles.”