28/07/2020

World’s Largest Falcon Faces A Threat It Can’t Flee: Climate Change

National Geographic - Text Douglas Main | Photographs Kiliii Yüyan

Scientists are working to better understand gyrfalcons, the only raptors that stay year-round in the Arctic, the fastest-warming region on Earth.
A gyrfalcon soars over the cliffs and tundra of Alaska’s Seward Peninsula. The birds are especially vulnerable to climate change because many stay year-round in the Arctic, the fastest-warming region on Earth.

The gyrfalcon is the world’s largest falcon, and one of the fastest: During long flights, it can surpass speeds of 80 miles per hour. Weighing more than three pounds, with a wingspan of four feet or more, it can take down prey twice its size.

It’s also the only Arctic raptor that doesn’t need to head south for the winter, staying behind instead to hunt prey in a frigid, dark landscape. “Any organism that can live in such a hostile environment has my respect,” says Travis Booms, a raptor biologist with the Alaska Department of Fish and Game.

But the gyrfalcon faces a challenge it cannot flee or take down: The Arctic is warming more than twice as fast as the rest of the planet, and biologists consider gyrfalcons one of the region’s most vulnerable species, in part because they’re ultra-specialized to survive in the cold. While many species are shifting their ranges toward the cooler poles as temperatures climb, the gyrfalcon can’t go any farther north. Though they’re not currently classified as threatened with extinction, recent research in Alaska suggests there’s cause for concern.

“The population is stable for now but may possibly be declining,” Booms says, though it’s unclear by just how much. “There are some pretty clear threats on the horizon.” He is part of a long-term study in the Seward Peninsula, in western Alaska—home to 70 to 80 nesting pairs of gyrfalcons, or about one-tenth of the state’s total population—to understand how the birds are adapting to climate change.

Source: IUCN

Photographer Kiliii Yüyan accompanied researchers visiting gyrfalcon nests on the peninsula in June 2019. His photos provide an unprecedented glimpse of the birds in their natural habitat, where they are very difficult to find and observe. He was drawn to the project by the birds’ beauty and their role as top predators in the Arctic, he says, as well as to the importance of the research.

Gyrfalcons and golden eagles compete for nesting spots on cliffs across vast, uninhabited stretches of the Arctic. This former eagle’s nest sits on a bluff over a river on the Seward Peninsula. The region is uniquely suitable for gyrfalcon research because its network of roads allows researchers easier access.

Left: These gyrfalcon chicks are about 25 days old and ready to be banded by biologists so they can be identified in the future. The researchers must hike for miles and rappel down cliffs to band the chicks and take measurements and blood samples.
Right: The youngsters are not immune to swarms of mosquitoes that arise during the heat of the summer. Scientists worry that avian diseases like West Nile virus, spread by mosquitoes, could migrate north as the area warms.

“We frankly still know so little about gyrfalcons,” he says, including how they manage to survive the winter and where they go then.

“I wanted to give people a close glimpse of this beautiful animal. There are so few images of gyrfalcons out there,” Yüyan says. “What does a gyrfalcon, aerial queen of the Arctic, look like in its own domain?”

Aeries, canaries

The Seward Peninsula is an ideal place to study gyrfalcons because it has a robust network of roads, a rarity in the Arctic. These extend from the small town of Nome and run within hiking distance of several gyrfalcon nesting sites, or aeries, perched high on rocky cliffs that rise above vast, uninhabited stretches of tundra.

Since 2014, the Peregrine Fund, an organization devoted to raptor conservation and research, has been studying the peninsula’s gyrfalcons in tandem with Booms and the Alaska Department of Fish and Game, which has been studying raptors there for 20 years.

Each summer, a team of researchers visits some 20 gyrfalcon nests on the peninsula at three different times: in May, when the eggs have been laid; in June, when chicks are about 25 days old; and in mid-July, after the chicks have fledged.

It’s not easy work. An average day requires hours of hiking through difficult terrain, crossing rivers, climbing and descending cliffs, and enduring swarms of mosquitoes. The June tour—when they take blood samples and measurements from the chicks, and place leg bands on them—is particularly difficult. The parents aren’t exactly pleased with the human visitors.

“It’s somewhat intimidating rappelling down a cliff toward a nest and having these large birds swooping at you [while] constantly screaming,” says Devin Johnson, a doctoral student at the University of Alaska Fairbanks who’s writing his dissertation on the links between gyrfalcons’ diet and reproductive success. (The researchers’ remote cameras show the birds quickly return to the nest and to a sense of normalcy after they leave.)

Data gathered from these field visits will illuminate how gyrfalcons are reacting to environmental changes in the area. These include more intense spring storms—which can kill nestlings—and the growth of new bushes and small trees across the tundra, which gives their prey more places to hide. The scientists have also begun sampling the raptors’ blood for diseases such avian malaria and West Nile virus, to which gyrfalcons are likely more vulnerable than other raptors.

“If environmental change is occurring, it will be manifested in the biology of gyrfalcons,” says David Anderson, who runs the Peregrine Fund’s gyrfalcon research program. “We use them as a canary in the coal mine.”

Young gyrfalcons high up in a cliffside nest devour prey delivered by their mother. A camera trap placed by the Peregrine Fund biologists helps researchers to monitor the chicks and see what they eat.
Four million photos

Learning more about gyrfalcons’ diet is an important part of the project because the birds prey almost exclusively on other animals that, like themselves, are specially adapted to live in the cold north. And like gyrfalcons, their prey are increasingly vulnerable in the warming Arctic, says Mike Henderson, a raptor biologist with the Peregrine Fund who manages the research program in the field.

Motion-activated cameras the researchers place at the nests every May capture photos of all the prey gyrfalcons bring back. Since 2014, the project has accrued more than four million photos of prey items—including ptarmigans, ground squirrels, lemmings, and songbirds. “We currently have more gyrfalcon diet photos than anyone in the world,” Henderson says.

Left: Feathers litter the ground alongside wildflowers growing near a gyrfalcon aerie. The raptors specialize in hunting ptarmigans, chicken-like ground birds, as well as ground squirrels, lemmings, and songbirds.
Right: This gyrfalcon, in Nome, Alaska, is cared for by local falconer John Earthman. "They're very engaging birds, highly intelligent," Earthman says. Many raptors used by falconers are caught “on the wing” after fledging in late summer or fall and released in the spring.

Their research shows the diet of gyrfalcons is more varied than previously thought. But as to whether their diet has already changed due to climate conditions, “it’s something we’re looking into—we really need a longer-term data set to know for sure,” Johnson says.

Hunters and guides

Though gyrfalcon populations appear stable globally, Booms says “there are some indications the species may be declining locally in western Alaska and the Yukon Territory.” The southernmost population being studied appears to be doing the worst, he says. The declines may be due in part to difficulty finding prey and more intense spring storms. But he says it’s too early to make definitive conclusions.

Michael Henderson, who manages the Peregrine Fund's gyrfalcon research project, cradles a recently banded juvenile gyrfalcon at a nest site.
The uncertainty is yet another reason why it’s important to monitor Alaska’s birds, to get baseline data before the area warms even more, Booms says.

Furthermore, a small number of gyrfalcons are legally taken from the wild each year for use in falconry, in which people train the raptors to help them hunt. Between about one and five are taken from nests in the state each year, in a highly regulated fashion, Booms says.

Gyrfalcons are not only valued hunters but they’re also spiritual guides for many Indigenous Arctic people. And that’s personal for Yüyan, because his ancestors are Nanai, Native people in the Siberia region.

“Some of the most powerful [spirit helpers] are falcons,” he says, including gyrfalcons. He says he wants to help people understand that the Arctic is more than a big expanse of ice. “It’s the last vast wilderness we have, with so much incredible life and Indigenous culture. If we don’t know what’s out there, we just assume there’s nothing. And keeping the Arctic exotic will doom it to exploitation.”

A female white gyrfalcon soars through the air near Nome. In certain areas, 10 percent of gyrfalcons have such bright white coloration. “Gyrfalcons, especially the ghostly white-morph birds, are so stunning visually,” says photographer Kiliii Yüyan. “Their size and ferocity intrigue me. They have an intensity and awareness that reminds me that wild creatures have a vastly different perspective than humans.”

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