Texas Parks & Wildlife Magazine   

Archives

Confessions of a Raven Maniac

Surviving on stealth, teamwork and a knack for acting, ravens are the con men of the bird world.

By Penelope Warren

“What’s your favorite bird?”

It’s one of those questions birders hear with predictable regularity. I’ve gone through an equally predictable sequence of stock answers, beginning with the obvious, “Oh, well, it’s impossible to choose just one,” progressing through “The newest bird on my life list,” to an admission of the bald truth: “I’m a raven maniac.” Non-birders will respond with a frown and “Oh, those big black things?” puzzled that the answer isn’t “painted buntings” or “mockingbirds” or something else stunningly beautiful or musical. Most other birders will pause, nod, acknowledging the choice even if they don’t share it. Every now and then, though, one gets a gleam in his eye, grins, and admits, “Oh, yeah. Me, too.”

The fact is ravens are special. The common raven is one of the most widely distributed of all birds and one of the most successful. It originated in the Old World, ranging across the breadth of Europe, a narrow strip of North Africa and most of Asia. From there it crossed into North America via the Bering land bridge, possibly scavenging the remains of mammoth and bison hunted by the humans who made the trek. Ravens spread south to Central America and east to the Atlantic, adapting to tundra and desert and everything in between, splitting into new species and subspecies as they went.

Today, Texas is home to both the original common raven (Corvus corax) and a later, strictly American branch of the family, the Chihuahuan raven (Corvus cryptoleucus) that developed in the New World after the initial migration. The common can be found in Big Bend and on the Edwards Plateau, while the Chihuahuan’s range overlaps and extends north into the Panhandle and south along the Rio Grande. The common is a bird of wild places, favoring mountains and forests. The Chihuahan is altogether more gregarious. A bird of grasslands and desert scrub, it happily winters in and around cities, taking advantage of landfills and exploiting even the litter tossed onto parking lots, poking into burger wrappers and corn chip bags for the last tasty crumbs.

Legend has always ascribed extraordinary powers to ravens. In Celtic myth, the war goddess Morrigan takes the form of a raven. A matched pair named Hugin (thought) and Munin (memory) were said to sit on the Norse god Odin’s shoulders and whisper news of the world into his ears. Western Native American nations saw Raven as both a creator spirit and a trickster, while others associated him with dark magic; in Cherokee, a ka’alana ayeliski, or raven-caller, is a two-heart, a shape shifter, a stealer of souls. Perhaps the most famous raven of all is Edgar Allan Poe’s incurably pessimistic bird, who “once upon a midnight dreary” stalks into the parlor of a grieving lover and croaks “Nevermore” in answer to each of his despairing questions.

Part of the raven’s mystique is sheer physical presence. Both Texas species are glossy black, with shaggy hackle feathers at the throat and wedge-shaped tails. Both have large, heavy bills adorned with bristles and an aristocratic Roman arch. At 22 to 27 inches long and up to 3.6 pounds, with a wingspread of about 4 feet, the common raven is larger than any other American songbird — yes, you read that right; songbird, even if it’s more Philip Glass than Mozart — and consistently larger than any but the high-end raptors such as eagles and great grey owls. The smaller Chihuahuan checks in at 19.5 inches, not as overbearing, but still a match, millimeter for millimeter, for a red-tailed or Swainson’s hawk. Perhaps most distinctive, both boast high-domed skulls that house brains as large, in relationship to their bodies, as those of chimpanzees. And recent research has begun to show that ravens use those brains in sometimes remarkable ways.

Scientists have long associated intelligence with two major factors. One is the ratio between brain size and total body mass. The bigger the brain in proportion to the body, the more intelligent the brain’s owner tends to be. This measure holds true with humans and non-human primates such as chimpanzees and gorillas; with the cetaceans (dolphins and whales); with elephants; and, among birds, with the parrot and corvid families. Besides several species of crows, the latter includes jays, magpies, nutcrackers and, of course, ravens.

Until very recently, the common wisdom among ornithologists was that all birds came equipped at hatching with a set of stereotypical responses to stimuli, with very little room for learning or originality. Mammalian brains — ours, chimpanzees’, whales’ and elephants’— are composed of two kinds of cells. The more “primitive” parts of our brain, which keep us breathing and digesting without having to think about it, are composed of bundles of neurons. The neocortex, which deals with abstract thought, creativity and problem solving, forms an overlay of flat cells in convoluted layers — the “gray matter.” Avian brains, in contrast, are smooth and appear to be made up of the same type of fiber bundles as the lower sections of the mammalian brain. Scattered through the bird forebrain, though, are clumps of gray matter.

Despite their very different architecture, we now know, the internal connections within bird and mammal brains are quite similar, including the pathways for processing visual information and vocal learning. This brings us back to the importance of relative size. Not all birds are potential Phi Beta Kappas — just the ones with big brains for their body mass and the lofty craniums to house them.

Several researchers have undertaken to test the extent of raven intelligence. One of the most prominent, Bernd Heinrich of the University of Vermont, devised an elegant experiment to test for insight, the ability to predict the results of an action. He suspended pieces of meat by long strings from a perch. One raven in the flock Heinrich was studying solved the problem by pulling the string up a few inches with his bill, grasping the loop with the talons of one foot, then hauling up another few inches of cord and holding that down until he arrived at the bait. Another bird took a more direct approach, pulling the string along parallel to the perch until the snack was within reach. Other birds either imitated the first two or devised strategies of their own. This set of experiments has recently been repeated at the Konrad Lorenz Institute in Grünau, Austria, where European ravens have proven just as inventive as their American cousins.

A big brain, though, is only part of the equation. The other factor that favors the development of intelligence is a complex, usually hierarchical, social context. Among both common and Chihuahuan ravens, immature birds form flocks that feed and roost together. Intricate status relationships develop among them, established by gender-specific displays. The would-be dominant male struts casually along the ground with his head and bill held high, his head and neck feathers puffed out. Long belly feathers droop over his skinny legs like an incongruous pair of tattered pants. The female fluffs out her neck feathers, flares her wings and makes a series of tok-tok-tok calls known as “knocking.” Ravens are unusual in that the dominant male and dominant female do not necessarily become a “Bill and Hill” power couple. Each may well choose a mate further down the social scale.

At sexual maturity, around the age of three, pairs split off from the group to claim territories that they will vigorously defend against interlopers. At the end of nesting season, Chihuahuans gather again into large flocks, to winter with other pairs and their offspring. Common ravens, though, maintain their solitary territories year round, defending carcasses and other food sources from flocks of youngsters and other strangers.

The lifelong pair bond is established well before young ravens are ready to mate and set up housekeeping on their own. A courting male tempts his prospective bride’s palate with choice morsels of grubs and bugs, the raven equivalent of a box of chocolates or maybe a three-martini lunch. She preens him, and he returns the favor. Both species of ravens perform spectacular courtship flights comprised of swoops, corkscrews, barrel rolls and plummeting dives with wings held close to the body, falcon fashion. Courting and mated pairs also fly serenely together, wingtip to wingtip. I have seen a pair of Chihuahuan ravens execute a graceful pas de deux, flying within inches of each other, separating only to skim the flowing air of a high thermal as it carried them upward, then glide down again, calling to each other. Common ravens may also lock talons while tumbling through the sky, one bird flying upside down beneath the other, fierce and tender at once, like eagles.

The precision that brings paired ravens together, talon matched for talon and wing for wing, can also be deadly in the high air. Ravens may fold their wings and drop like falcons in the sheer exuberance of play or to impress a partner, but they may also kill like falcons, striking their prey from above and bearing it to earth. On the ground, bonded pairs make formidable hunting teams. Ravens have been observed chasing squirrels and even young seals toward a waiting partner, who blocked escape and made the kill. Raven partners are also accomplished bandits and stick-up artists. One of a pair will distract a feeding hawk or fox, while the other darts in from behind and steals its dinner. On Wreda Island in the Baltic Sea, a raven was observed dragging a wing to feign injury, luring a swan off her nest while its partner snatched an egg. Butch and Sundance, move over.

Raven cooperation also extends to other species. Biologists assume, but 10,000 years later have no way to prove, that ravens followed Ice Age hunters across the Beringia land bridge, feeding on the offal discarded by the humans. Ravens’ relationship with wolves, on the other hand, is well attested. Ravens follow hunting packs and share their kills. In turn, ravens, whose formidable bills cannot tear through moose or deer hide, will call wolves to open a carcass and allow both species to feast together. The Lakota call them “wolf birds,” recognizing the kinship.

Ravens have fascinated humans for millennia because we see ourselves in them. Ravens are devoted partners and parents. Less admirably, they are also accomplished liars and thieves. They are opportunists, living by their wits. Yet ravens will share resources not just with their own, but with other species. (We humans are still working on that one.) They make us uncomfortable, inhabiting the uneasy intersection between life and death. Yet they are survivors, making their homes in deserts and on pack ice, where a black predator on white snow breaks all the rules and still succeeds.

Clever survivors that we are ourselves, we admire that. Maybe, if we’re honest, we even envy it a little.

back to top ^