Nesting peregrine falcons close Teton climbing routeby Kelsey Dayton
— May 27, 2014
The silhouette of a peregrine falcon is distinctive. There are the trademark pointed wings of a bird of prey in motion with powerful quick beats followed by a glide.
It’s body is small, weighing only one or two pounds. Yet it is ferocious when threatened and will take on a golden eagle or an unintentionally-intrusive climber.
For the fourth year in a row the popular climbing area, Baxter’s Pinnacle in Grand Teton National Park, closed this spring to accommodate a pair of nesting peregrine falcons. It’s a reminder of the bird’s power and ferocity (you don’t want to encounter one of these birds while in a climbing). Closing the climb protects humans as well as the birds that can swoop dangerously close to them. And the necessity to close the climb is a sign of the bird’s incredible resilience, making a robust comeback after reaching the brink of extinction.
Decades ago the birds almost went extinct due to the introduction of DDT — “dichlorodiphenyltrichloroethane,” the insecticide blamed for, among other things, thinning the shells of the birds, destroying chicks before they could hatch. Steve Cain, senior wildlife biologist in Grand Teton National Park, said falcons — at the top of their food chain — ate insects, birds and fish that ingested DDT. By the mid-1960s there were almost no peregrines left in the Yellowstone ecosystem, said Cain.
The decline of the peregrines was statewide, according to Bob Oakleaf, a recently retired non-game coordinator with Wyoming Game and Fish.
“It wasn’t noticeable. They just disappeared,” he said.
The species’ adaptability allowed it to reproduce in captivity, which allowed the population to rebound faster than most believed possible. They were removed from the endangered species list in 1999.
“The tail end of (the reintroduction process) really exploded,” Oakleaf said.
There are more than 100 locations in the state where peregrines nest today. While there isn’t early data to compare whether those areas are the same as before the animals died off, it is likely the birds returned to reoccupy the places they once thrived, Oakleaf said.
Cain arrived in Grand Teton in 1989 as the park was finishing its hacking operations for the falcons. Hacking is a way to reintroduce birds to the wild by building a plywood box set on a cliff by helicopter. The boxes are built to supply the birds food without human contact and in the falcon’s natural environment. When the chicks reached fledging age, one side of the box was opened, allowing the birds to fledge on their own but return to the hack site for food until they gained enough hunting experience to adequately feed themselves.
It was an amazing testament to the bird’s ability to adapt even without parents to model behavior, Cain said. There were two hacking sites in Grand Teton National Park: one in Death Canyon, and one in Webb Canyon.
Cain remembers monitoring the birds.
“It was always a totally awesome experience to go back to the site and settle in for several hours for observation, and then all of a sudden one appears,” he said. “It’s fantastic.”
By 1989 there was one wild nesting pair in the park. In 1991 a second pair made its home in Webb Canyon. There were three pairs in the late 1990s and in 2011 the pair near Baxter’s Pinnacle was discovered after the birds began diving at climbers ascending Baxter’s near a nest.
“They are fearless,” Cain said. “They are one of the most exquisite avian predators for their flying ability.”
As predators they are also an important part of the ecosystem. The park is now home to four known nesting pairs, the ones in Webb and Garnet Canyons, the pair at Baxter’s and one in the John D. Rockefeller Parkway, said John Stephenson, wildlife biologist with Grand Teton National Park. Areas of Garnet Canyon, also a popular spot for climbers, have been closed at times to protect the birds’ nests. While the falcons return to the same area to nest, they sometimes move to different sides of the canyon. Recently, they haven’t settled in areas of Garnet Canyon that warrant closures, he said.
These four territories are monitored by park staff to track which sites are occupied and how many young fledge. The birds lay one to four eggs. Biologists can tell if the birds are incubating eggs, but not how many, Stephenson said. Eggs hatch near the end of May or early June, and the young fledge in mid- or late July. The Baxter’s pair has fledged a chick every year other than in 2012, since the nest was discovered in 2011, Stephenson said.
Four pairs is considered a success and a stable population in the park, but the park could likely support one or two more pairs, Cain said.
Peregrine falcons make their nests on cliff ledges where they can prey on other birds and protect their young from predators like Great Horned owls. The migratory birds head to South America or the Gulf Coast during the winter and return to Wyoming in April.
While there is always worry about the bird’s future, the birds are resilient. Cain said that with seasonal closures in nesting areas the birds no longer face unnatural threats.
Baxter’s Pinnacle is expected to reopen in August. It could open earlier if the nest fails this year and no chicks fledge.
— “Peaks to Plains” is a blog focusing on Wyoming’s outdoors and communities. Kelsey Dayton is a freelancer and the editor of Outdoors Unlimited, the magazine of the Outdoor Writers Association of America. She has worked as a reporter for the Gillette News-Record, Jackson Hole News&Guide and the Casper Star Tribune. Contact Kelsey at [email protected] Follow her on twitter: @Kelsey_Dayton
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