A Million Falcons Went Missing. Here’s How They Were Found

Most birds of prey are loners. They might form huge flocks during migration, but for the rest of the year, they stick to themselves. The red-footed falcon is different. This kestrel-size bird frequently travels and roosts in large groups across Eastern Europe and Central Asia. It even nests in colonies, with hundreds of pairs of slate gray males and buffy-red females all living together in what Hungarian ornithologist Péter Palatitz calls “super-busy cities.” Within these avian metropolises, the falcons fight for nests, steal from each other, mate outside their partnerships, and leave eggs for others to raise. For scientists interested in how birds behave, “this system is a heaven,” says Palatitz, who has studied the falcons for 20 years.

These raptors don’t build their own cities. Instead, they occupy the abandoned nests of the rook, a relative of crows. But rooks have long been seen as agricultural pests and were so thoroughly persecuted in the 1980s and ’90s that their population crashed. The red-footed falcons, with nowhere to nest, plummeted to a quarter of their former numbers. In 2006, Palatitz launched a plan to reverse that decline by placing thousands of nest boxes throughout Hungary. The falcons responded enthusiastically. Over the next decade, their numbers doubled.

As the falcons rebounded, Palatitz took the opportunity to answer some long-standing questions about these little-studied creatures. For example, he knew that they winter in Africa but not their route or specific destination—key information for understanding how the species spends half its life. So, between 2009 and 2015, Palatitz and his team fitted 28 individuals with satellite transmitters. The devices revealed that the birds, which weigh just four to seven ounces, can cross the Mediterranean and the Sahara in a nonstop five-day flight. A week later, they end their 6,000-mile trek in southern Africa, where they stay for months.

But in resolving one mystery, Palatitz unearthed another. The tracking data hinted that in March, before returning north, the red-footed falcons all pass through the same small stretch of central Angola. Why? Some of the team thought this was a coincidence, but Palatitz argued that the birds were gathering at a huge roosting site. He bet a beer that he was right, and began making plans to visit Angola.

Traveling in Angola can be risky, as more than 14,000 acres of land are still contaminated with mines—a legacy of the country’s nearly three decades of civil war. For years, Palatitz couldn’t get permission to go outside the capital, Luanda. But in late 2018, he was introduced to José “Zeca” Agostinho, an Angolan who had spent decades doing de-mining work, including in Huambo Province, where the falcons seemed to be congregating. Agostinho lined up the right paperwork, and “our 10-year dreams came together in three months,” Palatitz says. By March 2019, the team was on the road to Huambo. And on their second day of searching, Palatitz won his beer.

The team came across a site where falcons streamed in from all directions, blackening the sky. Some darted around at eye level. Others wheeled overhead. They perched shoulder to shoulder on every available branch. As he watched them, Palatitz started crying. It was like being “in a new dimension,” he says, “like I’m not part of the Earth but I’m more part of the sky.”

Palatitz knew the falcons were sociable, but he had completely underestimated just how sociable they could be. In the summer, the birds are spread across thousands of miles from Hungary to Kazakhstan. But for six weeks in February and March, every last one passes through this tiny, 1.5-square-mile region of central Angola, which the team now calls “Falcopolis.”

True to their scientific name, Falco vespertinus—“falcon of the evening”—the birds begin to gather as sunlight dims. For over an hour, hundreds of thousands of them swirl above the trees and hover in place as they look for perches. “You can actually feel the wind from their wings on your face,” Agostinho tells me. Their droppings whitewash the underlying grass and fill the air with an ammonia-like scent. Their slate and red feathers blaze in the sunset, and he says that when they finally land, mere inches apart, “it’s like the trees are blossoming.”

No one knows exactly how many red-footed falcons congregate at Falcopolis. “Estimating them in the sky is impossible,” Palatitz says. Instead, his team is trying to count the birds by measuring the area over which they roost and the carrying capacity of those trees. If successful, the team will have an unprecedented way of counting a species that, in the summer, is scattered over a vast and largely unmonitored area. The red-footed falcon population has been estimated at up to 400,000 individuals. At Falcopolis, “I think I’ve seen one million birds in the air,” Palatitz says.

What compels these falcons to gather in such preposterous numbers? And why do they come to that particular part of Angola? “We don’t know,” Palatitz says. But he has some guesses. Falcopolis is on a peninsula surrounded by rivers and is easy to find from the air, he explains. Its climate is temperate and agreeable. It’s got plenty of large roosting trees. Human presence may have helped the falcons by suppressing mammalian competitors and predators. And since agriculture isn’t practiced intensively, there are still plenty of insects around. In particular, every March winged termites burst from the ground, swarming so densely that they look like static on an old television set.

(World’s Largest Falcon Faces a Threat It Can’t Flee: Climate Change.)

Gorging on the termite bonanza, the falcons increase their weight by 20 to 30 percent, gaining the fat they need to return to their breeding grounds, against the Sahara’s headwinds. And Palatitz suspects that their communal nature might help them find the unpredictable swarms. Every night, the falcons regurgitate pellets full of undigested termite heads, which might allow the birds to see who among them is successfully hunting—and thus worth following to increase their own luck. This hypothesis is one of many ideas that Palatitz now wants to test. By collecting blood samples from the falcons, he hopes to figure out how they avoid a species-wide epidemic despite bringing in pathogens from across the world. And by tagging more individuals with GPS transmitters, he is trying to understand how their migratory behavior changes over time.

By migrating, the red-footed falcons exploit the riches of two hemispheres. But their versatility also creates vulnerability—a bird that depends on several nations is susceptible to threats in any one. In Angola, hunting is a problem. The civil war decimated the country’s native mammals and livestock, depriving many communities of protein. The falcons offer an alternative, and boys use flashlights to flush the birds out before killing them with slingshots and sticks. By surveying local markets, Agostinho at one point estimated that tens of thousands of falcons were being killed annually. And though hunting wild animals has been largely prohibited, regulations have been unevenly enforced and assumed by many to apply only to big game. The falcons’ habitat is also at risk. Pesticides, which are increasingly used, could devastate the termite swarms the falcons need. All of Falcopolis’s trees could easily be cut for firewood or burned to clear space for agricultural land.

Conversely, Falcopolis’s small size also means that a small number of communities will determine the birds’ fate, and that Palatitz’s team knows where to concentrate its efforts. Agostinho, who coordinates with national authorities and now leads a conservation nonprofit called Orbis Angola, has been raising awareness about the falcons at surrounding schools and churches, and with the local soba—influential traditional leaders. The teams have set up a research camp to document the locals’ knowledge about the birds and enlist their help with banding and conservation measures. They’re also talking with donors about supplying people with gas stoves or solar cookers to reduce their need for firewood.

Meanwhile, news of Falcopolis is spreading quickly. At a recent conference, Angola’s president described it as a national treasure. The Ministry of the Environment went to the site, marking the first high-level governmental visit to the area in decades. A six-foot-tall falcon statue now stands in the main square of the nearest municipality, Mungo. And Palatitz’s team has started bringing international volunteers to Falcopolis, where Agostinho is training locals to guide future tourists.

These efforts are already paying off. When Agostinho first visited Mungo, he found falcons on sale in the market. “That’s gone completely,” he says. Perhaps more important, locals are increasingly venturing out of their homes at night to see the birds for themselves. And as they become invested, they’re coming up with their own ways of protecting the birds.

Earlier this year, five 12-year-old boys told Agostinho that they had formed a soccer team, the Mungo Falcons. They would use their matches as opportunities to educate similarly aged kids—the demographic most likely to hunt the birds—about protecting the raptors. They’d play for the falcons; they just needed a ball. So Agostinho bought this new generation of ambassadors their first one.

Red-footed falcons, like other spectacular migrants, show how connected our planet is—and needs to be. Their success depends on wild resources as disparate as rook nests in Europe and termite swarms in Africa. And their future will hinge upon equally far-flung feats of human grace, from nest boxes in Hungary to soccer balls in Angola.

(Inside a Sheikh's Plan to Protect the World's Fastest Animal.)