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Whether crows, ravens, and other “corvids” are making multipart tools like hooked sticks to reach grubs, solving geometry puzzles made famous by Aesop, or nudging a clueless hedgehog across a highway before it becomes roadkill, they have long impressed scientists with their intelligence and creativity.

Now the birds can add one more feather to their brainiac claims: Research unveiled on Thursday in Science finds that crows know what they know and can ponder the content of their own minds, a manifestation of higher intelligence and analytical thought long believed the sole province of humans and a few other higher mammals.

A second study, also in Science, looked in unprecedented detail at the neuroanatomy of pigeons and barn owls, finding hints to the basis of their intelligence that likely applies to corvids’, too.


“Together, the two papers show that intelligence/consciousness are grounded in connectivity and activity patterns of neurons” in the most neuron-dense part of the bird brain, called the pallium, neurobiologist Suzana Herculano-Houzel of Vanderbilt University, who wrote an analysis of the studies for Science, told STAT. “Brains can appear diverse, and at the same time share profound similarities. The extent to which similar properties present themselves might be simply a matter of scale: how many neurons are available to work.”

Understanding the minds of nonhuman animals promises to shed light on the origins of such cognitive abilities as, in this case, knowing and analyzing the contents of one’s own brain. That’s how people solve challenges and make discoveries — what do I know? what if I look at it this way? — and it’s a pillar of higher intelligence. Knowing what you know is also a form of consciousness, and the discovery that more and more nonhumans seem to have it raises tricky questions about how we treat them.


“It has been a good week for bird brains!” said crow expert John Marzluff of the University of Washington, who was not involved in the new studies. In particular, the discovery that crows know what they know will not surprise avian scientists, “who have increasingly demonstrated the cognitive abilities of birds, … but they will be relieved! This research is groundbreaking.”

To test whether crows know and can analyze the contents of their brains, neurobiologist Andreas Nieder of the University of Tübingen in Germany trained two birds to peck a red or a blue target on a panel, depending whether they saw a faint light. Nieder kept varying the “rule,” with the birds told which color meant what — red = saw it, or blue = saw it — only after the flash. That required the crows, Glenn and Ozzy, to keep monitoring their brains; they had a second or two to figure out what they had seen and tell Nieder by choosing the corresponding target.

While the crows were solving these tasks, the researchers were tracking the activity of hundreds of their neurons. (Crows’ brains have 1.5 billion neurons, as many as some monkey species.)

When the crows reported having seen a faint light, sensory neurons were active between the flash and the birds pecking the color that meant, yes, I saw that. If the crows did not perceive the very same faint stimulus, the nerve cells remained silent, and the bird pecked, no, I didn’t see anything. Ozzy and Glenn’s brain activity systematically changed depending on whether or not they had perceived the dim flash.

During the delay, many neurons responded according to the crows’ impending report, rather than to the brightness of the light. “A population of neurons contained information about the crows’ subjective experience throughout the trial,” the scientists wrote.

The birds were aware of what they subjectively perceived, flash or no flash, correctly reporting what their sensory neurons recorded, Nieder told STAT. “I think it demonstrates convincingly that crows and probably other advanced birds have sensory awareness, in the sense that they have specific subjective experiences that they can communicate,” he said. “Besides crows, this kind of neurobiological evidence for sensory consciousness only exists in humans and macaque monkeys.”

The study shows that neurons in the most complex part of the crows’ brain, the pallium, “do have activity that represents not what was shown to them, but what they later report,” said Herculano-Houzel. Neurons “represent what the animals next report to have seen — whether or not that is what they were shown,” she said. The neurons figure this out, so to speak, during the time lapse between when Nieder tells the birds the rule and when they peck the target to indicate their answer.

“That’s exactly what one would expect from neurons that participated in building the thoughts that we later report,” she said, suggesting that corvids “are as cognitively capable as monkeys and even great apes.”

A second study looked in unprecedented detail at the neuroanatomy of pigeons and barn owls, finding hints to the basis of their intelligence that likely applies to corvids’, too. Scientists have long known that crows and ravens have unusually large forebrains, but unlike mammals’ forebrains — the neocortex — corvids’ do not have the six connected layers thought to produce higher intelligence. But theirs do have “connectivity patterns … reminiscent of the neocortex,” scientists led by Martin Stacho of Ruhr-University in Germany reported.

Specifically, the pigeons’ and owls’ neurons meet at right angles, forming computational circuits organized in columns. “The avian version of this connectivity blueprint could conceivably generate computational properties reminiscent of the [mammalian] neocortex,” they write. “[S]imilar microcircuits … achieve largely identical cognitive outcomes from seemingly vastly different forebrains.” That is, evolution invented connected, circuit-laden brain structure at least twice.

“In theory, any brain that has a large number of neurons connected into associative circuitry … could be expected to add flexibility and complexity to behavior,” said Herculano-Houzel. “That is my favorite operational definition of intelligence: behavioral flexibility.”

That enables pigeons to home, count, and be as trainable as monkeys. But for sheer smarts we’re still in the corvid camp. A 2014 study showed that New Caledonian crows, rooks, and European jays can solve an Aesop’s Fable challenge, dropping stones into a water-filled tube to bring a floating bit of food within reach, something kids generally can’t do until age 7. These birds were the first nonhuman animals to solve the task.

  • Just recently purchsed a crow “call” for my husband to call the crows to our back yard. They are rewarded with treats and they respond to call by swarming our backyard. Although a bit scarey at first it is now just as much friendship and entertainment. A connection with Mother Earth and her beautiful creations!

  • Thank you, dear Sharon Begley for this material. I’d like to inform you that my collegues in Biology Department, Moscow State University – Zoya Zorina and Anna Smirnova ([email protected], [email protected], [email protected]) work for many years in the area of crow intellect or reasoning ability. Their work demonstrated that these birds are able to solve the cognitive tasks which even monkeys fail to solve (but apes – can). It would be great if you will have the possibility to make the paper about their work. Best, thank you again, Inga Poletaeva

  • It is becoming more clear that real intelligence quotient is measured in terms of connecting things of several domains, experiences and perspectives as opposed to the number of credentials one possesses. My working definition of intelligence is the creative power to connect things of diverse aspects. Example Given: Artificial General Intelligence. Even artificial super intelligence is associated with connectivity and thus an internet mechanism of diverse entities. In linking AI invention with the invisible animal-aided model mentioned Revelation 4:6-8, l have helped the doubting world to understand how AI operates and how it is going to take us through and thus, removing the unwarranted fear and suspicions surrounding AI innovation (Chanda Chansonso:2020).

  • Crows are even smarter than people think. When competing for a pile of seeds with a bunch of squirrels, I’ve seen them pluck a single hair from the squirrel’s tail to distract him. The squirrel turns around and the crow gets the seeds. That’s at least as smart as a fifth grader.

    I’ve also seen crows visit my deck for a water bowl I set out in a drought. Not just for water, but they bring dry bread from the bakery dumpster two miles away, to dip it in the water and soften it.

    I’ve also seen them bury a sunflower seed in a potted plant. To hide the seed from the squirrels and get the seed later, right? Wrong — they come back later when it’s sprouted and eat the shoots. It seems to me like they’re farming. They don’t just bury the seed in the dry dirt, they bury them in the potted plants that they know we are watering.

    • I ve seen crows doing the same you mention: using my cats’ water bowl to soften some dried stuff they wanted to eat.

      I think humans have had for too long a exagerated good impression of their own superiority. It is probably related to the idea of soul and God, but it for too long hindered and slowed down the research not only of animal intelligence, but mainly of human mental diseases and their treatment.

      Because of this in the ’80 I was starting to think that the developments in computers was a good indirect way to also accept and study without prejudice how the human brain works.

  • I have long been intrigued by birds, especially crows and the intelligence one can discern in their eye contact. (1) I used to rise before 6 a.m. to swim in my condo complex daily. My laps also included the side stroke and back stroke, which I enjoyed because I could hear the crows call and watch them flying overhead to group up with others nearby. Before I finished my laps, they would part from the meet-up, then fly back over head. Members of the crow group would peer down as I swam. Occasionally one would look down and caw. Then one day, I hadn’t watched any news yet and was swimming on my side when the crows flew overhead. For the first and only time, they ‘paused’ and flew in a circle 3x overhead, taking moments to peer down at this strange human, until the leader cawed loudly thrice and they flew off. I could tell you exactly what day that was because later I took my neighborhood walk of several miles and passed a neighborhood store. I was stunned to see the morning newspaper in the coin operated paper bin. Headlines shouted that Princess Diana had been killed in the accident overnight. I have never seen crows fly like that since, and having moved away, am not likely to again. I know they had no idea about global events, but it was odd that it was such a memorable day. (2) More than a decade later, I worked in an office with a view of a small lake surrounded by trees along the south side of the parking lot. Many varieties of birds were often spotted, Mexican Eagles, wild parrots, Coopers Hawks, Crows, Blue Herons, Egrets, Bald Eagles and more. One stressful morning, a group of 5 crows flew in and landed in an oak tree directly outside my office window. My desk was aligned against the window with about 8′ between me and the feathered visitors. As they picked their acorns, cracked them against the trunk and chomped on them, the lead crow peered at me, then turned to his sidekick and (in short caws), seemed to laugh, motion it’s head my way as if to say, hey, they keep these humans locked up in cages, too! Those two seemed to share a laugh, gazed at me with reddish eyes, then the others joined in the cawfest. Just before departing, the lead crow peered at me, cawed loudly and they flew off. (Sadly, 4 days later the bldg. mgmt. cut down the oaks by the office windows.) For the rest of the duration of my job, I would often see them out and about. On rare occasions, if the crows spotted me, one might give 2 caws (I always imagined them remarking, look, that one escaped!). Whenever I remember that incident and my original befuddlement, I have to laugh out loud. Fascinating creatures.

  • they have gathered here strangely, out of the blue (it mentions this in the bible)…… are we to be joyous or concerned? 55 yrs. have never seen this.
    God be with His chosen people. In Jesus’ name…. amen

  • I have witnessed Raven gatherings… Numerous Ravens that are not normally here where I live will come and they gather. More than 50 birds. Not often. How do they know to all come to one place? I assume it is mental telepathy.

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