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12 Fascinating Facts About Crows

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Crows often get a bad rap. In many Western cultures, they've historically been associated with death, disease, and bad omens, reviled as crop-stealers by farmers, and condemned as nuisances by city dwellers. But the birds are fascinating creatures, adaptable and brainy to an extent that's almost scary. Here are a few facts about the corvids that might surprise you.

1. ALL CROWS AND RAVENS BELONG TO THE SAME GENUS.

Members of the Corvus genus can be found on every continent except Antarctica and South America (although other close relatives live there). To date, scientists have named 40 species. Colloquially, some of them are referred to as ravens while others are called crows or jackdaws.

Historically, the name raven has been given to several of the big-bodied Corvus birds with shaggy feathers on their necks. Mid-sized members of the genus are usually called crows, while the very smallest species go by the name jackdaws. There's also a large-beaked outlier known as the rook, which was named after the unusual sound it makes. But pervasive as these labels may be, they're not scientific and do not reflect the latest research. Despite its informal name, the so-called Australian raven is more closely akin to the Torresian crow than it is to the common raven.

In the U.S., when people talk about crows and ravens, they're usually referring to the American crow (Corvus brachyrhynchos) and the common raven (Corvus corax). Telling them apart can be tough, but it is possible for eagle-eyed birders. One big indicator is size: The common raven is much larger, about the size of a red-tailed hawk. It also has a more wedge-shaped tail. As Kevin J. McGowan of the Cornell Lab of Ornithology writes on his crow FAQ page, ravens soar longer than crows, and you can see through their wing feathers as they fly (among other differences). And the birds' calls are substantially different. "American crows make the familiar caw-caw, but also have a large repertoire of rattles, clicks, and even clear bell-like notes," McGowan writes, whereas common ravens have "a deep, reverberating croaking or gronk-gronk. Only occasionally will a raven make a call similar to a crow's caw, but even then it is so deep as to be fairly easily distinguished from a real crow."

You can hear crow vocalizations here and raven vocalizations here.

2. OLDER SIBLINGS CAN HELP THEIR PARENTS RAISE NEWBORN CHICKS.

Like a lot of intelligent animals, most crows are quite social. For instance, American crows spend most of the year living in pairs (they usually mate for life) or small family groups. During the winter months, they'll congregate with hundreds or even thousands of their peers to sleep together at night in a sprawling communal unit called a roost.

Come nesting season, a mated pair of crows might be lucky enough to receive chick-rearing help. Juvenile birds are frequently seen defending their parents' nest from predators. Other services they can provide include bringing food to mom and dad, or feeding their younger siblings directly. One study found that 80 percent of American crow nests surveyed had a helping hand. And some birds become regular nest assistants, providing aid to their parents for over half a decade.

3. WHEN A CROW DIES, ITS NEIGHBORS MAY THROW A FUNERAL.

The sight of a dead crow tends to attract a mob of a hundred or more live ones. During this ritual, the live crows almost never touch the dead one, which rules scavenging out as a motive. Why do they do this? Some studies suggest that the mass gathering is part of a survival strategy: The birds are learning about threats and seem hesitant to revisit any spot where they've encountered a dead crow, even if food is plentiful there.

4. THEY'VE CAUSED BLACKOUTS IN JAPAN.

Since the 1990s, crows have experienced a population boom in Japan, where—not coincidentally—delicious garbage is more plentiful than ever before. This is bad news for power companies. Urban crows like to nest on electric transformers and will often use wire hangers or fiberoptic cables as building materials for their nests. The result was an epidemic of crow-caused blackouts in major cities around Japan: Between 2006 and 2008, the corvids stole almost 1400 fiberoptic cables from Tokyo power providers, and according to the Chubu electric company, crows are responsible for around 100 power failures per year in their facilities alone.

To fight back, Chubu started installing artificial "love nests" in 2004. Made with non-conductive resin, the nests are placed on company towers high above the power lines, where the birds are unlikely to cause any trouble. The strategy seems to be working: 67 percent of the faux nests are currently in use, making life a lot easier for Chubu employees.

5. PROPORTIONALLY, THE BRAINS OF SOME CROWS ARE BIGGER THAN YOURS.

According to McGowan, crows are "smarter than many undergraduates, but probably not as smart as ravens."

Crows are so smart and so good at improvising that some zoologists admiringly call them "feathered apes." And yet, from a primate's perspective, crow brains might look puny. The New Caledonian crow, for example, has a brain that weighs just 0.26 ounces. But relative to its body size, that brain is huge, accounting for 2.7 percent of the bird's overall weight. By comparison, an adult human's three-pound brain represents 1.9 percent of their body weight.

Of all the living birds, crows, ravens, and parrots have the biggest brain-to-body size ratios. And in lab experiments, these avians show a degree of cognition that puts them on par with the great apes. In fact, research has shown that they have a much higher density of neurons in their forebrains than primates do. The amount of neurons in this region is thought to correlate with a given animal's intelligence. Theoretically, having more neurons translates to better cognitive reasoning. Thus, it looks like crows, ravens, and parrots have enviable minds indeed.

6. CROWS HAVE REGIONAL DIALECTS—WHICH THEY CAN DELIBERATELY CHANGE.

Apart from the famous caw, caw noise, crows emit a number of other sounds. Each one sends out a different message; for example, cawing can be used as a territorial warning—or a way for crows to signal their location to relatives.

This avian language isn't homogeneous; two different populations of crows may have slight differences. As ornithologist John M. Marzluff and author Tony Angell noted in their 2005 book In the Company of Crows and Ravens, the calls these birds use "vary regionally, like human dialects that can vary from valley to valley." And there's more: If a crow changes its social group, the bird will try to fit in by talking like the popular guys. "When crows join a new flock," Marzluff and Angell wrote, "they learn the flock's dialect by mimicking the calls of dominant flock members."

7. CERTAIN CROWS KNOW HOW TO READ TRAFFIC LIGHTS.

In Japan, carrion crows (Corvus corone) use cars like oversized kitchen appliances. The birds have learned to take walnuts—a favorite treat—over to road intersections, where they put the hard-shelled snacks down onto the pavement. The crow then waits for a passing vehicle to smash the nut, after which it will swoop down and eat the delicious interior.

It's a risky trick, but the crows aren't usually run over because (unlike some people) they've figured out what traffic lights mean. Carrion crows wait until the light turns red before flying down to place the un-cracked nut on the road. The second the light goes green, the crow takes off to watch the nut get run over from afar; it will even wait for the next red to scoop up the nut's insides.

This behavior isn't limited to just one corvid species: American crows have been observed doing the same thing in California.

8. THEY CAN RECOGNIZE YOUR FACE—AND HOLD A GRUDGE.

You don't want a crow for an enemy. In 2011, a team from the University of Washington published a remarkable study about the brainpower of local crows. The researchers' goal was to figure out how well the birds could identify human faces. So—in the name of science—they went out and bought two Halloween masks: One resembled a caveman, the other looked like Dick Cheney. It was decided that the caveman getup would be used to threaten the birds, while the Cheney mask was relegated to control status.

At the five sites, a scientist donned the caveman mask before catching and banding some wild crows. Getting trapped is never a fun experience, and upon their release, the ex-captives loudly "scolded" their assailant with a threatening caw. Seeing this, other birds who had been sitting nearby joined in the fray, swooping down to harass the neanderthalic visitor. Over a period of several years, both masks were regularly worn by team members on strolls through all five test spots. Without fail, the caveman mask was greeted by angry scolds and dive-bomb attacks from crows—including many who'd never been captured or banded—while the birds largely ignored the Dick Cheney mask.

Amazingly, the caveman disguise continued to provoke a hostile response five years into the experiment—even though the team had stopped trapping crows after those first few site visits. And some of the birds who antagonized the mask-wearer weren't even alive back when the whole thing started. The younger crows couldn't possibly have seen the imitation caveman grab an acquaintance of theirs—but they scolded it anyway. Clearly, the grudge had been passed on; birds were still attacking the mask as recently as 2013.

The moral of this story? Mind your manners around crows. Because if you mistreat them, they won't forget you and neither will their friends—or the next generation.

9. NEW CALEDONIAN CROWS MAKE AND USE TOOLS.

Lots of non-human animals, including chimpanzees and orangutans, create useful implements which help them survive in the wild. The New Caledonian crow (Corvus moneduloides) is one of only two species on the planet that can craft its own hooks in the wild. The other is called Homo sapiens. The South Pacific avian uses the hooks—which are made from pliable twigs that the crows bend using their beaks and feet into a J-shape—to extract insects from tight crevices.

Another surprising attribute is this species' weirdly shaped maw. Unlike virtually all other birds, the New Caledonian crow has a bill that does not curve downwards. For years, the quirk went unexplained, but scientists now think that the avian's unique beak evolved to help it grasp tools more easily, as well as to better see what the tool is doing.

The New Caledonian crow isn't the only implement expert in the corvid family. In 2016, scientists at the University of St. Andrews demonstrated that the ultra-rare Hawaiian crow, or ‘Alalā (Corvus hawaiiensis), is similarly adept at using and modifying tools.

10. THE BIRDS FIGHT OFF PREDATORS BY GANGING UP ON THEM.

Crows have to deal with a menagerie of predators, such as hawks, owls, coyotes, and raccoons. To ward them off, the corvids exploit the fact that there can be strength in numbers. Upon seeing a would-be attacker, crows are known to gather en masse, with some groups consisting of a dozen birds or more. Individual crows then swoop down to deliver passing blows with their beaks, often inflicting serious bodily injury in the process. If all goes well, the target will back off—though it may kill a few of the dive-bombers before they retreat. Of course, corvids are by no means the only avians that mob would-be attackers. Swallows, chickadees, and even hummingbirds have all been documented doing this. In fact, crows are sometimes at the receiving end of mob violence as smaller songbirds often feel threatened by them and lash out collectively.

11. CORVIDS UNDERSTAND A THING OR TWO ABOUT IMPULSE CONTROL.

A 2014 study shows that at least some corvids can resist the urge for instant gratification—if you make it worth their while. The research was led by University of Göttingen graduate student Friederike Hillemann, whose team assembled five common ravens and seven carrion crows. Through careful note-taking, the scientists figured out what the favorite meal items of all 12 animals were. Then the experiment began.

With an outstretched hand, one of the researchers gave each of their birds a morsel of food. Then, the animals were shown a different piece of grub. The corvids were made to understand that if they liked the second option better, they could swap snacks—but only if they were willing to sit patiently for a certain period of time first. If a bird ate the original treat during that stretch, it forfeited the chance to trade it for a new one.

Hillemann's results showed that the crows and ravens didn't mind waiting around for an improved snack option. As such, a bird with a piece of bread was content to sit quietly if it knew that some fried pork fat would eventually be gained in the trade-off. However, if that same bird's second choice was another piece of bread, sitting tight would be pointless. So understandably, corvids who were put in this kind of situation tended to go ahead and eat whatever they'd been given. Why wait for more of the same?

12. YOU CAN CALL A GROUP OF CROWS A MURDER, BUT SOME SCIENTISTS WOULD RATHER YOU DIDN'T.

According to the Oxford English Dictionary (OED), the correct term for a group of crows is a murder, an expression bird-watchers and poets have been using since at least the 15th century, which the OED speculates may allude "to the crow's traditional association with violent death, or … to its harsh and raucous cry." But maybe it's time to come up with a replacement. McGowan hates the phrase "murder of crows." To him, it only feeds the public's negative outlook on the animals. "These birds aren't a gang of nasty villains," he wrote in the book Birdology. "These birds are just birds." McGowan would also have you know that American crows rank among "the most family-oriented birds in the world."

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Pig Island: Sun, Sand, and Swine Await You in the Bahamas
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When most people visit the Bahamas, they’re thinking about a vacation filled with sun, sand, and swimming—not swine. But you can get all four of those things if you visit Big Major Cay.

Big Major Cay, also now known as “Pig Island” for obvious reasons, is part of the Exuma Cays in the Bahamas. Exuma includes private islands owned by Johnny Depp, Tyler Perry, Faith Hill and Tim McGraw, and David Copperfield. Despite all of the local star power, the real attraction seems to be the family of feral pigs that has established Big Major Cay as their own. It’s hard to say how many are there—some reports say it’s a family of eight, while others say the numbers are up to 40. However big the band of roaming pigs is, none of them are shy: Their chief means of survival seems to be to swim right up to boats and beg for food, which the charmed tourists are happy to provide (although there are guidelines about the best way of feeding the pigs).

No one knows exactly how the pigs got there, but there are plenty of theories. Among them: 1) A nearby resort purposely released them more than a decade ago, hoping to attract tourists. 2) Sailors dropped them off on the island, intending to dine on pork once they were able to dock for a longer of period of time. For one reason or another, the sailors never returned. 3) They’re descendants of domesticated pigs from a nearby island. When residents complained about the original domesticated pigs, their owners solved the problem by dropping them off at Big Major Cay, which was uninhabited. 4) The pigs survived a shipwreck. The ship’s passengers did not.

The purposeful tourist trap theory is probably the least likely—VICE reports that the James Bond movie Thunderball was shot on a neighboring island in the 1960s, and the swimming swine were there then.

Though multiple articles reference how “adorable” the pigs are, don’t be fooled. One captain warns, “They’ll eat anything and everything—including fingers.”

Here they are in action in a video from National Geographic:

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13 Secrets From the Ravenmaster at the Tower of London
Christine Colby
Christine Colby

Christopher Skaife is a Yeoman Warder at the Tower of London, an ancient fortress that has been used as a jail, royal residence, and more. There are 37 Yeoman Warders, popularly known as Beefeaters, but Skaife has what might be the coolest title of them all: He is the Ravenmaster. His job is to maintain the health and safety of the flock of ravens (also called an “unkindness” or a “conspiracy”) that live within the Tower walls. According to a foreboding legend with many variations, if there aren’t at least six ravens living within the Tower, both the Tower and the monarchy will fall. (No pressure, Chris!)

Skaife has worked at the Tower for 11 years, and has many stories to tell. Recently, Mental Floss visited him to learn more about his life in service of the ravens.

1. MILITARY SERVICE IS REQUIRED.

All Yeoman Warders must have at least 22 years of military service to qualify for the position and have earned a good-conduct medal. Skaife served for 24 years—he was a machine-gun specialist and is an expert in survival and interrogation resistance. He is also a qualified falconer.

Skaife started out as a regular Yeoman Warder who had no particular experience with birds. The Ravenmaster at the time "saw something in him," Skaife says, and introduced him to the ravens, who apparently liked him—and the rest is history. He did, however, have to complete a five-year apprenticeship with the previous Ravenmaster.

2. HE LIVES ON-SITE.

The Tower of London photographed at night
Christine Colby

As tradition going back 700 years, all Yeoman Warders and their families live within the Tower walls. Right now about 150 people, including a doctor and a chaplain, claim the Tower of London as their home address.

3. BUT HE’S HAD TO MOVE.

Skaife used to live next to the Bloody Tower, but had to move to a different apartment within the grounds because his first one was “too haunted.” He doesn’t really believe in ghosts, he says, but does put stock in “echoes of the past.” He once spoke to a little girl who was sitting near the raven cages, and when he turned around, she had disappeared. He also claims that things in his apartment inexplicably move around, particularly Christmas-related items.

4. THE RAVENS ENJOY SOME UNUSUAL SNACKS.

The Ravenmaster at the Tower of London bending down to feed one of his ravens
Christine Colby

The birds are fed nuts, berries, fruit, mice, rats, chicken, and blood-soaked biscuits. (“And what they nick off the tourists,” Skaife says.) He has also seen a raven attack and kill a pigeon in three minutes.

5. THEY GET A LULLABY.

Each evening, Skaife whistles a special tone to call the ravens to bed—they’re tucked into spacious, airy cages to protect them from predators such as foxes.

6. THERE’S A DIVA.

One of the ravens doesn’t join the others in their nighttime lodgings. Merlina, the star raven, is a bit friendlier to humans but doesn’t get on with the rest of the birds. She has her own private box inside the Queen’s House, which she reaches by climbing a tiny ladder.

7. ONE OF THEM HAS EARNED THE NICKNAME “THE BLACK WIDOW.”

Ravens normally pair off for life, but one of the birds at the Tower, Munin, has managed to get her first two mates killed. With both, she lured them high atop the White Tower, higher than they were capable of flying down from, since their wings are kept trimmed. Husband #1 fell to his death. The second one had better luck coasting down on his wings, but went too far and fell into the Thames, where he drowned. Munin is now partnered with a much younger male.

8. THERE IS A SECRET PUB INSIDE THE TOWER.

Only the Yeoman Warders, their families, and invited guests can go inside a secret pub on the Tower grounds. Naturally, the Yeoman Warder’s Club offers Beefeater Bitter beer and Beefeater gin. It’s lavishly decorated in police and military memorabilia, such as patches from U.S. police departments. There is also an area by the bar where a section of the wall has been dug into and encased in glass, showing items found in an archaeological excavation of the moat, such as soldiers’ discarded clay pipes, a cannonball, and some mouse skeletons.

9. … AND A SECRET HAND.

The Byward Tower, which was built in the 13th century by King Henry III, is now used as the main entrance to the Tower for visitors. It has a secret glass brick set into the wall that most people don’t notice. When you peer inside, you’ll see it contains a human hand (presumably fake). It was put in there at some point as a bit of a joke to scare children, but ended up being walled in from the other side, so is now in there permanently.

10. HE HAS A SIDE PROJECT.

Skaife considers himself primarily a storyteller, and loves sharing tales of what he calls “Victorian melodrama.” In addition to his work at the Tower, he also runs Grave Matters, a Facebook page and a blog, as a collaboration with medical historian and writer Dr. Lindsey Fitzharris. Together they post about the history of executions, torture, and punishment.

11. THE TOWER IS MUPPET-FAMOUS.

2013’s Muppets Most Wanted was the first major film to shoot inside the Tower walls. At the Yeoman Warder’s Club, you can still sit in the same booth the Muppets occupied while they were in the pub.

12. IF YOU VISIT, KEEP AN EYE ON YOUR MONEY.

Ravens are very clever and known for stealing things from tourists, especially coins. They will strut around with the coin in their beak and then bury it, while trying to hide the site from the other birds.

13. … AND ON YOUR EYES.

Skaife, who’s covered in scars from raven bites, says, “They don’t like humans at all unless they’re dying or dead. Although they do love eyes.” He once had a Twitter follower, who is an organ donor, offer his eyes to the ravens after his death. Skaife declined.

This story first ran in 2015.

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