In 1833, a young Charles Darwin met an animal in the Falkland Islands that he couldn’t explain: a large, social, strangely inquisitive bird of prey that looked and acted like a cross between an eagle and a raven. Birds of this species were “tame and curious,” Darwin wrote, and they seemed to be studying him: they stared intently at human visitors with wide, dark eyes, and he watched in amazement as they stole hats, compasses, and other items from the crew of the HMS Beagle.
Sealers and whalers who frequented the Falklands were well acquainted with the birds and their antics. Some called them “flying devils” or “flying monkeys,” and one marooned sailor declared them “the most mischievous of all the feathered creation.” Darwin was intrigued by them, and couldn’t understand why they were confined to a remote corner of the globe. “This bird,” he mused, “doubtless for some good reason, has chosen these islands for its metropolis.”
The mystery of the Falklands’ flying monkeys lies at the heart of my book A Most Remarkable Creature, which follows these unusual birds—now called striated caracaras (Phalcoboenus australis)—and their nearest relatives into the deep past to answer Darwin’s question. The journey often reminded me that even if animals are known to science, they aren’t necessarily known by science: the 10 living species of caracaras are poorly studied compared to their counterparts in the Northern Hemisphere. They range in size from that of a jay to that of a red-tailed hawk, and at least one can be found in every part of South America, from the high deserts of the Andes to the Amazon rainforests. Most are versatile scavengers and opportunists, and Darwin couldn’t figure out exactly what they were: caracaras’ hooked beaks and strong talons marked them as predators, but their behavior reminded him of crows and their kin—“a tribe of birds widely distributed over the rest of the world, but entirely absent from South America.”
The movement of continents wasn’t discovered until decades after Darwin’s death, but if he’d known about it, he likely would have seen that the caracaras—and the missing crows—were a reflection of South America’s geologic history. It had been a giant island for tens of millions of years, joining hands with North America only in the relatively recent past. After the Cretaceous extinction killed three-quarters of our planet’s plant and animal species 66 million years ago, South America’s isolated survivors pursued their own evolutionary paths, along with new arrivals who blew in on the wind or crossed an ephemeral land bridge from a warm, forested Antarctica. These immigrants included the ancestors of caracaras, which are neither eagles nor crows: they’re an ancient lineage of falcons, more closely related to parrots than to other birds of prey. Many uniquely South American animals died out after humans reached the continent thousands of years ago, but the caracaras have survived and learned to live with us.
Despite these achievements, western ornithologists have often given caracaras short shrift. A pair of venerable raptor specialists dismissed them as “a rather unimpressive lot” as recently as the 1960s, and even Darwin called them “false eagles” who “ill become so high a rank.” Amerindian cultures, however, have celebrated them: a Toba legend from northern Argentina credits southern crested caracaras (Caracara plancus) with teaching humans the secrets of fire and medicine, and the Incas reserved the privilege of wearing the feathers of mountain caracaras (Phalcoboenus megalopterus) for the emperor alone. In 1889, the South American–born writer and naturalist William Henry Hudson argued that small caracaras called chimangos (Phalcoboenus chimango), common on his family’s farm in the Pampas, had been unjustly neglected by science. “A species so cosmopolitan in its habits,” he protested, “would have a whole volume to itself in England. Being only a poor foreigner, it has had no more than a few unfriendly paragraphs bestowed upon it.”
More than a century later, scientists are beginning to agree. Researchers in Argentina have shown that chimangos can swiftly teach one another to recognize and exploit unfamiliar new resources—including garbage bags and pizza boxes—while captive striated caracaras show a fondness for puzzles and games that suggests a grasp of abstract concepts such as colors, shapes, numbers, and names. And in tropical French Guiana, studies of red-throated caracaras (Ibycter americanus) have revealed a bird of prey like no other: they live in family groups that resemble troops of monkeys, drive wasps from their nests to feed on their larvae, and may even use millipedes’ defensive secretions to repel mosquitos and other parasites. There’s much still to learn about these striking birds, but caracaras’ boldness, flexibility, and insight may point toward the evolutionary origins of birds’ increasingly recognized intelligence—and the enduring value of a curious mind.
Clarification (March 2): The original version of this article contained an outdated scientific name for southern crested caracaras, which has been corrected. The Scientist regrets any confusion.