鈥婨ditor's Note: Members of the crow family, known as the corvids, are among the smartest birds in the world. Some are capable of using tools, playing tricks, teaching each other new things, even holding 鈥渇unerals.鈥� And yet there鈥檚 still much we don鈥檛 know about these fascinating, sometimes confounding creatures. What鈥檚 going on inside the mind of a corvid? Three leading scientists are finding answers.

John Marzluff | American Crows (below)

Tim Shields | Common Ravens

Nicky Clayton | Eurasian Jays  

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The crows in your neighborhood know your block better than you do. They know the garbage truck routes. They know which kids drop animal crackers and which ones throw rocks. They , and they might even play with the friendly ones. If you feed them, they probably not only recognize you but your car as well, and they might just leave you trinkets in return. These birds live their lives intertwined with ours, carefully observing us even as most of us barely take note of them. That鈥檚 how they survive, and they鈥檙e good at it: In recent decades the American Crow has taken over our suburbs, and even moved into the hearts of our big cities. As we鈥檝e reshaped the landscape, we鈥檝e created an ideal environment for an animal that is canny and perceptive enough to exploit our riches.

Exactly how the crow mind recognizes the opportunities we unwittingly provide is mostly an open question, says University of Washington wildlife biologist John Marzluff, who has studied corvids and their behavior for more than 35 years. He鈥檚 collected countless stories over the decades about crows鈥� complex social lives, including how they play, deceive each other, hold 鈥渇unerals鈥� around their dead, and seemingly learn from one another鈥攅ven banding together to mob humans who have somehow wronged one of their own. Marzluff has a knack for figuring out how to quantify these intriguing behaviors in rigorous scientific experiments. By testing how the birds remember, communicate, and learn, his team is gaining insights into why crows are so street-smart and how they manage to thrive in our world. 鈥淏eing open to possibility is important, so that you don鈥檛 miss really interesting new things that nobody thought these birds could do,鈥� Marzluff says.

For the past several years he has been spying on crows鈥� thoughts to figure out what makes them tick. On a December morning a few of us are gathered in the small-animal neuroimaging lab in the University of Washington Medical Center to see a wild crow鈥檚 brain at work. Marzluff and graduate student Loma Pendergraft are testing how the crow processes the sight of food and the feeding calls of other birds.

The subject hops restlessly from perch to perch in a cage as Pendergraft plays a recording of wild crows in the midst of eating. A chorus of hoarse caws, fast double-caws, croaks, and barks fills the room; it鈥檚 as if we鈥檙e suddenly in the middle of a cornfield in summer.

But what is it like for this fidgety crow? These are his roost mates鈥� voices on the recording. Does he recognize them? Is his mouth watering as he anticipates the hunks of bread they鈥檙e cawing about?

Five minutes ago the bird was injected with a short-lived radioactive compound. As he listens, this tracer accumulates in the most active areas of his brain. In another few minutes, he鈥檒l be anesthetized and scanned using positron emission tomography (PET), which detects the radiation and maps out the parts of his brain that were most responsive to the recording. Marzluff鈥檚 team will combine this scan with those from 14  other American Crows. Just as in humans, different networks in crow brains regulate different thoughts and behaviors; although not much is yet known about how bird neuroanatomy connects to bird behavior, some regions of the brain seem roughly similar to mammalian areas that handle functions like memory, fear, vision, and reasoning. Whichever ones the compound concentrates in will suggest what all that cawing means to a crow: maybe a general alert, a food鈥檚-over-here signal, or possibly a warning for other birds to back off.

On the scanner monitor, the crow鈥檚 head looks monstrous鈥攁 chisel-like beak, huge bulbous eyeballs, and just a few hazy blobs indicating where brain action has taken place. The team won鈥檛 know which exact areas were busiest until later, after data analysis accounts for the background metabolic activity. But the crow鈥檚 work is done. Marzluff pulls the anesthesia mask away from its beak. Soon the crow鈥檚 eyelids begin to flutter. Pendergraft holds the groggy bird quietly in his lap for a few moments, making sure he doesn鈥檛 hurt himself flopping around. The crow is sleek and beautiful, his jet-black plumage glossy even in this harsh light. His long black toes, each armed with an impressive curved black talon, hang limp below Pendergraft鈥檚 hands.

The crow is waking up to a ring of people staring at him鈥攓uite likely the strangest experience of his life. But he does not struggle or squawk. He is still, and his black eyes are bright, watching us watching him. Watching.

Marzluff got hooked on corvids in graduate school, studying how mated pairs of Pinyon Jays in the mountains of northern Arizona recognize each other鈥檚 voices. These birds鈥� complex societies include dozens of large interrelated families, with dominance hierarchies and ruling lineages.

As he finished his Ph.D., Marzluff learned that famed behavioral ecologist Bernd Heinrich had begun working with wild ravens. I gotta get in on this, he thought, and he and his wife, Colleen, promptly moved to a one-room cabin in western Maine to begin working with Heinrich. (It was small enough that they could put another log on the fire without getting out of bed.) They spent the next three years huddled in blinds, watching ravens and other forest creatures feeding on the dead animals they left as bait. 鈥淚t was really rich,鈥� Marzluff says. 鈥淩eally primal.鈥�

A dead horse or moose in the winter is a meat bonanza, quickly claimed and defended by whichever raven pair inhabits that territory. If a wandering raven spots it, too, the Marzluffs learned, it鈥檒l enlist backup. 鈥淭he pair will kick your tail if you鈥檙e alone, so it pays to go back to the roost and recruit others,鈥� Marzluff says. Once a bird brings a minimum of nine allies, the territorial pair backs down.

Marzluff next moved to Idaho, spending seven years at the Snake River Birds of Prey National Conservation Area, advising the U.S. military on how its tank training exercises affected big raptors. He also got involved in a project to build captive populations of the Hawaiian Crow, which is extinct in the wild, by perfecting egg-hatching and chick-rearing techniques in close relatives: the American Crow, the Black-billed Magpie, and the Common Raven, which acted as surrogates for the island species. There are now 114 Hawaiian Crows in captivity, and some are being reintroduced to their former habitat this year.

Meanwhile, he kept thinking about the fascinating behavior he鈥檇 seen in wild birds鈥攖he way the animals organized their social groups, the groans and croaks and whispers that seemed so much like language. When Marzluff hired on at the University of Washington as an assistant professor in 1997, he could begin to explore the behavior of corvids in greater depth, by connecting lab-based experiments with tests of wild birds in action. American Crows were an obvious choice: There are plenty of them around Seattle, they鈥檙e easy to work with鈥攁nd they do interesting things.

All corvids have relatively big brains for their size. But while a seed storer like a Pinyon Jay or a nutcracker has a huge hippocampus鈥攁 region involved in memory鈥攃rows and ravens are more like primates. They have exceptionally large forebrains, the domain of  analytical thought, higher-level sensory processing, and flexible behavior. (Marzluff calls them flying monkeys.)

Experiments in the 1990s and early 2000s demonstrated that mammals ranging from monkeys to sheep could recognize individual human faces. People had often claimed that crows could recognize them, too, but Marzluff decided to actually test it.

As they trapped and banded crows around the University of Washington鈥檚 Seattle campus, he and his collaborators wore a latex caveman mask. When they later returned to those locations, either maskless or wearing a Dick Cheney mask the crows had never seen before, the birds ignored them. But anybody showing up in a caveman mask would spark a crowpocalypse. It wasn鈥檛 just the trapped birds that responded; apparently others had witnessed the abduction and remembered it. Whole gangs of crows followed the evildoer, scolding and dive-bombing. The birds knew that caveman face, and they didn鈥檛 like it one bit.

It was an impressive demonstration, says Heinrich, Marzluff鈥檚 former post-doc adviser: 鈥淗e put it on the map. The rest of us just took it for granted.鈥�

Every so often Marzluff鈥檚 group retests the birds. It鈥檚 been 10 years, and not only have the crows not forgotten, the knowledge keeps spreading. When a crow sees other birds mobbing, it joins in, learning and remembering the identity of the villain. Each time, more birds mob and scold. Nearly all of the birds originally trapped by the caveman are likely dead by now, yet the legend of Seattle鈥檚 Great Crow Satan still grows.

Brain-imaging follow-up revealed that faces associated with threats activated brain circuitry that鈥檚 analogous to well-known fear learning loops in mammals. Since these are some of the first behavioral imaging studies in wild birds, we don鈥檛 really know what it all means, cautions crow expert Kevin McGowan, a behavioral ecologist at the Cornell Lab of Ornithology. 鈥淚t鈥檚 new, and it鈥檚 cool, but it鈥檚 like everything else: We need to get a bunch more data before we can see what the picture is.鈥�

Recently, Marzluff鈥檚 graduate student Kaeli Swift turned to another corvid oddity. When crows see a corpse of one of their own species, they often gather around the dead bird, cawing noisily and then silently departing. Is it grief? Fear? A corvid Irish wake?

To find out, Swift fed wild crows in the same spot for three days. (It turns out they have a particular .) Next she staged one of three scary scenarios to instigate a gathering: a masked volunteer holding an evidently dead crow (actually a stuffed specimen); a masked volunteer standing near a lifelike taxidermy Red-tailed Hawk (a dangerous crow predator); or a masked volunteer near both the hawk and the crow. In all cases, crows formed mobs of a dozen or so angry, raucous birds.

The following three days, the birds were measurably slower to approach the place for handouts. Many of them also remembered the masks associated with the dead crow. When someone wearing one of those masks showed up weeks later with no taxidermy props, the crows scolded and sometimes mobbed. In the paper she published with Marzluff last fall, Swift proposed that 鈥渇unerals鈥� are a teachable moment, in which the birds collectively make an association between potential danger and a particular spot or predator.

These experiments help to show why crows are so successful. They need only one experience to form a long-lasting memory of who can be trusted and who can鈥檛鈥攅ssential knowledge when you鈥檙e dealing with humans who might either feed you or shoot you. Crows also share information, allowing individuals to adapt to rapid environmental changes much faster than if they learned on their own.

The studies also get to the questions that any observant person begins to ask when watching a crow: What in the world is that bird doing, and why? Despite establishing a global reputation for his research, Marzluff hasn鈥檛 lost touch with that moment of wonder. 鈥淗e just has fun,鈥� says Willamette University biologist David Craig, who collaborated with Marzluff on the caveman mask study. 鈥淚t鈥檚 a blast to spend field time with him. He鈥檚 maintained a curiosity-driven research agenda at the highest level.鈥�

It鈥檚 a damp, gloomy evening in December, and the University of Washington Bothell campus is boiling with crows. They litter the grassy hill. They choke the tennis courts. Crows alight on the buildings and crows perch in the nearby Douglas firs. Many just stand patiently in the drizzle, like commuters in black trench coats waiting for the bus. Once it鈥檚 completely dark, they鈥檒l join roughly 10,000 other crows in the winter roost in the wetlands just beyond.

Marzluff and I walk down to the roost. Every one of the hundreds of trees is festooned with crows, their black silhouettes sharp against the pale branches. It鈥檚 eerie, like a portal to an elfin realm. 鈥淚t鈥檚 a great natural spectacle,鈥� says Marzluff. 鈥淚 think it鈥檚 the coolest thing ever.鈥�

The American Crow is what urban ecologists call an 鈥渆xploiter鈥濃€攁 species that not only tolerates humans but flourishes alongside us. It is far from the only one, as Marzluff has shown. A pioneer in urban ecology鈥攖he study of life in areas where we live, work, and play鈥攈e launched a long-term project in 1998 to explore how land use and development affect birds.

His team monitored more than two dozen locales in the city, in the suburbs, and in forested areas, some of which were slated for development. Four times every breeding season, they鈥檇 count birds, monitor nests, and tag fledglings. By 2010 they had , documenting more than 55,000 individual birds from 111 species.

The upshot, as Marzluff describes in his latest book, Welcome to Subirdia (2014), is this: Although some species disappeared as forests were converted to suburbs, many did quite well. Seattle suburbs host 30 bird species to the forests鈥� 20, including Song Sparrows, American Goldfinches, Anna鈥檚 Hummingbirds, and Pileated Woodpeckers. Many birds lived longer and reproduced better in the suburbs than in the forests. It鈥檚 not that surprising, Marzluff says. Low-density suburbs include a diversity of habitats, from woodsy lots to shrubby gardens to open areas. Plus, we supply birds with seed and suet, set up nest boxes, and eliminate many natural predators.

Marzluff does not soft-pedal the damage that development does to wild places or the threats faced by 鈥渁voider鈥� species like Pacific Wrens and Swainson鈥檚 Thrushes. In the study, some of these birds basically vanished from all but the forested reserves.

But the study suggests that we could treat backyards more seriously as . We can replace lawns with native vegetation, and provide food. We can mark windows so birds don鈥檛 fly into them, and keep cats indoors. We can maintain dead trees for birds to nest in, or set out nesting boxes. It鈥檚 more than feel-goodism. Bigger suburban bird populations will have better chances to survive the monumental threat of climate change.

From Marzluff鈥檚 point of view, these two lines of research connect via conservation. The only wild animals that many of us see regularly are pigeons and crows, but conserving species requires sacrifices that people won鈥檛 make unless they believe that wild animals are worth protecting. That鈥檚 one big reason Marzluff has written four books about corvids, partnering with illustrators to create appealing, accessible works. Backyard birds鈥攍ike the perplexing, amusing, exasperating crow鈥攃an open people鈥檚 minds. Changing people鈥檚 attitudes and spurring them to create bird-friendly yards or take other personal action is harder than just preserving one piece of land, Marzluff admits. 鈥淏ut it鈥檚 a better long-term strategy.鈥�

We鈥檙e standing on the side of a four-lane highway on the outer fringe of Seattle, and it鈥檚 not exactly a breathtaking wilderness. There鈥檚 a big gravel lot, a recycling yard, and an RV self-storage facility in view. But there鈥檚 also a creek, grass here and there, and a few clusters of conifers鈥攁 mixed landscape, the kind that Marzluff鈥檚 research suggests can be bird heaven.

This morning Marzluff will release nine crows used for Pendergraft鈥檚 experiment here, where they were trapped two months ago. He lifts a dog crate out of his car and sets it down on the gravel. He opens the door and steps back. Nothing happens.

He leans over, peers through the airholes: 鈥淗ey, you鈥檙e free!鈥�

A moment later, a crow bursts out, flying fast with deep strokes of its powerful wings. It banks, heading west toward a thicket of bare trees a few hundred yards away. The bird lands in an upper branch and shuffles its feathers and tail, as if to shake off the indignities of the dog carrier and the humans who have been poking and prodding it for weeks.

The rest of the birds, six of them in a second crate, follow one by one, exploding out of the crates and then coasting in to land near the first bird. As we watch, a few other crows join them. It鈥檚 hard not to imagine that our bad reputation is now spreading, that Marzluff鈥檚 crows are telling their wild friends: You鈥檒l never believe what those crazy people over there did to me.

In any case, for us humans below, it seems obvious that something must be going on between these birds, some form of communication that we haven鈥檛 yet even begun to crack. They know us so well, but we have much to learn about them.

Within 10 minutes, all the crows are gone.