Scientists tested crows on their ability to recognize “geometric regularity,” a skill previously assumed to be unique to humans

Sarah Kuta – Daily CorrespondentApril 14, 2025

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Crows are arguably among the smartest creatures on the planet, possessing some cognitive abilities that rival those of 5- to 7-year-old human children. Now, a new study adds basic geometry to the list of subjects these brainy birds seem to be able to master.

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In a paper published in the journal Science Advances last week, researchers report that carrion crows can recognize “geometric regularity,” meaning they may discern traits like length of sides, parallel lines, right angles and symmetry. In the study, they could tell the difference between shapes like stars, crescents and squares, as well as between squares and irregular figures with four sides.

Researchers once thought this ability was unique to humans. But the findings suggest that’s not true—and they hint at the possibility that other species may be capable of similar feats, too.

“The crows show a sort of intuitive, strictly perceptual recognition of geometric properties,” says Giorgio Vallortigara, a neuroscientist at the University of Trento in Italy who was not involved with the work, to Scientific American’s Gayoung Lee.

To test the birds’ mathematical abilities, scientists in Germany placed two male carrion crows (Corvus corone) in front of a digital screen in a laboratory. They displayed six shapes on the screen, then trained the birds to peck at the outlier—the one that looked different from all the others. Whenever the birds chose correctly, researchers rewarded them with a tasty snack, either a mealworm or a bird seed pellet.Report This Ad

At first, the researchers made the outliers obvious—such as one flower amid five crescents, reports NPR’s Nell Greenfieldboyce. But as the birds got more comfortable with the task at hand, the team made the experiment increasingly challenging. They showed the crows similar-looking squares, parallelograms and other irregular four-sided figures.

Even as the game got more difficult, the crows could still pick out the outlier. They continued correctly pecking at the outlier, even after the scientists stopped giving them treats.

Why would crows need to be able to tell shapes apart? Researchers don’t know for sure. But they suspect this ability may help them with navigation and orientation as they fly around, they write in the paper. The birds may also have developed this ability to help them forage for food or identify other individual crows—including mates—based on their facial features.

“All these capabilities, at the end of the day, from a biological point of view, have evolved because they provide a survival advantage or a reproductive advantage,” study senior author Andreas Nieder, a neurophysiologist at the University of Tübingen in Germany, tells Scientific American.Report This Ad

In the future, researchers hope to investigate which areas of the birds’ brains are helping them excel at geometry. Birds don’t have a cerebral cortex—at least, not in the same way that humans do. But for us, that part of the brain is responsible for thinking and other complex functions. Crows still have these abilities, so the researchers posit there must be something else going on inside their heads.

“Obviously, evolution found two different ways of giving rise to behaviorally flexible animals,” Nieder says to Scientific American.

The team also hopes future research will probe the “geometric regularity” abilities of other species. In the past, researchers have run similar experiments with baboons. But even after extensive training, the primates didn’t seem to share our mathematical understanding.

Still, scientists say it’s unlikely that humans and crows are the only animals with this ability. “It’s just now opening this field of investigation,” Nieder tells NPR.Report This Ad

Crows are the whiz kids of the animal kingdom. Past research has found that they can vocally count up to four, distinguish between human voices and faces, and grasp a pattern-forming concept thought to be unique to humans. Some species can build tools for future use, while others are likely aware of their own body size.

These and other examples of animals’ intelligence are upending the long-held notion that humans are the only species capable of high-level cognitive functioning.

“Humans do not have a monopoly on skills such as numerical thinking, abstraction, tool manufacture and planning ahead,” Heather Williams, a biologist at Williams College, told CNN’s Scottie Andrew last year. “No one should be surprised that crows are ‘smart.’”

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• Tim Eisele
• // April 16, 2025
• https://www.outdoornews.com/2025/04/16/commentary-no-season-needed-on-sandhill-cranes-in-wisconsin/

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The proposal for a hunting season on sandhill cranes, like all hunting seasons, should be made based on biological information and sociological concerns.

To paint people who oppose a hunting season as anti-hunters or as those without an interest in hunting, is dead wrong. I hunt, am from a family with a history of hunting, and I oppose opening a season on sandhill cranes in Wisconsin.

I don’t believe a season on sandhill cranes is right for Wisconsin. I realize other states with big populations of sandhill cranes, such as Nebraska, also have declined to have a season on sandhills. So not opening a hunting season on this unique bird is not unusual.

If the reason for a hunting season is solely based on crop damage, there is a seed additive, called Avipel, that farmers can use to treat their corn and help deter cranes from eating tender young shoots.

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To further help farmers, Gov. Tony Evers has proposed adding $3.7 million each year to the new state budget for an abatement assistance program for corn producers. It will help to reimburse producers for the purchase of the seed treatment that discourages sandhill cranes from eating the seed.

This is just a start. Hopefully, in the future research will come up with additional ways to deter sandhill cranes from damaging other crops, such as potatoes.

The Wisconsin Legislative Council Study Committee on Sandhill Cranes should have recommended updating the agricultural damage law to allow farmers to get reimbursed for damage caused by sandhill cranes.

Currently the law requires a species to be hunted in order to pay crop damage to farmers. By adding cranes, without requiring that a species be hunted, would have helped farmers throughout the state much more than a limited hunting season in the fall when damage takes place in the spring.

Even that law has an inconsistency because it allows damage from mountain lions to be paid out, yet mountain lions are not legally hunted in Wisconsin. This was another opportunity for the legislative study committee to REALLY study the problem and come up with alternate solutions.

There are other alternatives to help farmers – one that is on this spring’s Conservation Congress April 14 agenda, that of issuing a conservation stamp to help pay for ag damage caused by cranes.

This would allow all citizens to contribute to help pay farmers for crop damages. And, indeed, wildlife belongs to ALL citizens, as noted in the North American Model of Wildlife Management. Everyone should be involved in funding damage to crops that everyone consumes.

Wisconsin is not ready for a sandhill crane hunting season.

Why not? Because sandhill cranes are special. They have long been considered a non-game bird. They have not been hunted for decades. To many citizens, they are a harbinger, just as are robins, of the arrival of spring.

Just because the federal government allows states in the Mississippi Flyway to hold a season on sandhill cranes, does that mean that Wisconsin has to participate?

Would such a season pass the smell test?

Precedent shows that years ago other states in the Mississippi Flyway held an early season on teal, but Wisconsin held off because it was considered an important breeding ground for blue-winged and green-winged teal. What is hunted in one state is not always appropriate for every other state.

Human attitude surveys show that citizens have legitimate concerns. A study conducted by the UW Survey Center in 2024 found only 17% of state residents would support a sandhill crane season, while 48% opposed it.

To say that all hunters support a crane season is misleading. In 2017, the Conservation Congress asked a question about beginning a crane season and it won, but just barely by 300 votes: 2,349 voting yes and 2,049 voting no. It was rejected in 18 counties.

Although open to the public, anyone who has attended the spring Conservation Congress meetings realizes that most of the people who attend are hunters, trappers, and anglers.

What is not needed is a season on sandhill cranes.

What is needed is to bring hunters and non-hunters together so that both carry their fair share of funding for natural resources management, not further divide them.

In Wisconsin, natural resources management is funded by license sales. If you don’t have a hunting, fishing, or trapping license in your pocket or purse, you are not the major funder for wildlife management, fisheries management, and conservation law enforcement.

We need non-hunters to have some skin in the game. I’d point to Minnesota’s 3⁄8 of 1% on the sales tax that helps to continue natural resources funding in that state.

Wisconsin needs hunters and non-hunters to work together to support natural resources. A sandhill crane season will only cause a larger divide between both groups.

Tim Eisele, of Madison, is a freelance outdoor writer/photographer and a third-generation Wisconsin hunter whose love has always been waterfowl hunting.