Although cultures around the world may regard the crow as a scavenger, bad omen, or simply a nuisance, this bad reputation might overshadow what could be regarded as the crow’s most striking characteristic – its intelligence. New research indicates that crows are among the brightest animals in the world. NATURE’s A Murder of Crows brings you these so-called feathered apes, as you have never seen them before. Buy the DVD. This film premiered October 24, 2010.

American Crow in Ontario, Canada. Photo by J.P. Moczulski © 2009 A Murder of Crows, Inc.

Crows are members of the Corvidae family, which also includes ravens, magpies, and blue jays. Loud, rambunctious, and very intelligent, crows are most often associated with a long history of fear and loathing. They are considered pests by farmers trying to protect their crops and seedlings. Many people fear them simply because of their black feathers, which are often associating them with death. But research demonstrated in A Murder of Crows proves crows are actually very social and caring creatures, and also among the smartest animals on the planet.

Where do crows live?
Crows live all over the world, except for Antarctica.

What do they eat?
Crows are predators and scavengers, which means that they will eat practically anything. Their diet consists of various road-kill, insects, frogs, snakes, mice, corn, human fast food, even eggs and nestlings of other birds. An adult crow needs about 11 ounces of food daily.

How many species are there?
There are about 40 or so species in the Corvus genus. These range from pigeon-sized birds to ravens, which can be as much as 24-27 inches long.

Social Environment
Crows are very social and have a tight-knit family. They roost in huge numbers (in the thousands) to protect themselves from enemies like red-tailed hawks, horned-owls, and raccoons. Crows also use at least 250 different calls. The distress call brings other crows to their aid, as crows will defend unrelated crows. Crows mate for life.

Close Relatives
The Corvus genus includes the common American crow, ravens, rooks, and other variations, and the wider family (Corvidae) includes jays, magpies, nutcrackers, and other birds.

Crows and West Nile Virus
Crows are susceptible to West Nile virus, and their deaths are used as early indicators of potential human disease in an area. West Nile Virus has killed 45% of American crows since 1999, though they’re still listed as Least Concern species by the International Union for Conservation of Nature.

What’s a murder of crows?
A group of crows is called a “murder.” There are several different explanations for the origin of this term, mostly based on old folk tales and superstitions.

For instance, there is a folktale that crows will gather and decide the capital fate of another crow.

Many view the appearance of crows as an omen of death because ravens and crows are scavengers and are generally associated with dead bodies, battlefields, and cemeteries, and they’re thought to circle in large numbers above sites where animals or people are expected to soon die.

But the term “murder of crows” mostly reflects a time when groupings of many animals had colorful and poetic names. Other fun examples of “group” names include: an ostentation of peacocks, a parliament of owls, a knot frogs, and a skulk of foxes.

Crows live everywhere in the world except Antarctica and are a part of myths and legends in many cultures. Their reputation in the stories varies from comical to frightening, godlike or wise, bringers of light and bringers of death, though a “murder” of crows refers to a flock of crows, and not to anything murderous, at all. They may be all these things, but what we are learning is that they are especially smart.

New research has shown that they are among the most intelligent animals on the planet. They use tools as only elephants and chimpanzees do, and recognize 250 distinct calls. One particular talent they have been discovered to possess is the ability to recognize individual human faces and pick them out of a crowd up to two years later – a trick that might make even Hitchcock shiver with fright.

They thrive wherever people live and have used their great intelligence to adapt again and again to a constantly changing world. Some memorize garbage truck routes, and follow the feast from day to day. Others drop nuts in the road and wait for passing cars to crack them open. And some build their nests from items we throw away – like wire clothes hangers.

These are social birds that mate for life and raise their young for up to five years. And they learn from each other’s misfortunes. When one is killed in a farmer’s field, it’s not uncommon for them to change entire migratory patterns so that no crows fly over that field for as long as two years.

These birds might have a scary reputation, but what may prove to be the scariest thing about them is how much they know about us, and how little we know about them!

A Murder of Crows premieres Sunday, October 24 at 8:00 PM.

Filmmaker Susan Fleming describes the awe-inspiring sight of a massive crow roost and explains with infrared imagery how crows retain heat during the night.

NATURE’s Ravens explores how these all-black creatures acquired their dual and contradictory images — as birds of both life and death.

Long recognized as one of the most intelligent birds, the raven also has a less than savory image throughout history as a scavenger that does not discriminate between humans and animals.

Ingenious and versatile, ravens are members of the crow family, which includes jays and magpies. They are found everywhere in the northern hemisphere and adapt to very different terrain, from deserts to mountains — a feat requiring high intelligence.

They learn to find food even in the harshest conditions, such as the dead of winter in Yellowstone National Park. As scavengers, ravens know how and when to take advantage of other animals to help them cadge a meal they couldn’t otherwise reach. In Yellowstone, bison that don’t survive the harsh winter attract coyotes, whose sharp teeth and strong jaws rip open the tough, frozen hides — making the meat accessible to watchful ravens. They also have been seen following wild wolf packs to a kill; some stories even have ravens flying ahead of the wolves to lead them to prey.

To order a copy of Ravens, please visit the NATURE Shop.

Online content for Ravens was originally published December 2001.

Generally, birds don’t get credit for being smart animals. Just think of the way the expression “bird-brained” is used. But corvids, which include magpies, crows, and ravens in particular, flutter in the face of this negative stereotype. Their behavior is often so clever, cunning, fun-loving, smart, and witty that it has motivated researchers to try to explain why. In fact, some scientists consider these black-feathered scavengers’ position on the intelligence spectrum to be on par with canids such as wolves, coyotes, and dogs, and have conducted experiments to try to quantify the raven’s brainpower.

In NATURE’s Ravens we see zoologist Bernd Heinrich of the University of Vermont work with ravens to see whether they could learn to distinguish between strings bearing food and strings bearing rocks and modify their behavior based on their understanding. The ravens performed well, even when the level of difficulty was increased by crossing the strings.

Heinrich has also used anecdotal evidence to point to raven cognitive intelligence. For example, the researcher flushed a bird off a frozen chunk of suet and observed upon inspection that the raven used its beak to carve a precise groove around the fat, allowing it to carry off a large chunk at once instead of several small morsels to eat one at a time. Heinrich commented that “the raven not only had thought ahead, but also had acted on that thought and shown intelligence.”

A central question that presents itself is whether the raven’s sharp behavior indicates complex cognitive processes associated with human learning. Johannes Fritz and Kurt Kotrschal of the University of Vienna, Austria, attempted to provide an answer with an experiment similar to Heinrich’s. Ravens were asked to perform a task — opening a box to get a reward — and then teach the behavior to their fellow birds. According to Henry Gee of Nature Magazine Online, while the birds’ performance indicates a high learning level, the results are inconclusive because it’s impossible to tell how the ravens learn: is it by a complex form of “imitative learning” or by a lesser process known as “stimulus enhancement”?

Gee suggests that while ravens might learn by stimulus enhancement, which means that a learner raven might simply come to link the act of opening a box with getting a reward, it seems likely that the corvids engage in imitative learning, which Gee states is “considered to be the most demanding category of social learning, because it requires the learner to translate what it sees (sensory input) into its own actions (motor output).”

How then can one account for corvids’ seemingly complex decision-making skills? After all, birds don’t have a cerebral cortex, so at one time their actions were considered robotic in nature. But in the 1960s, neurologist Stanley Cobb found that birds have a part in the forebrain, called the hyperstraiatum, that allows them to perform synonymous functions, and that ravens have among the largest brains of any birds as well as a relatively high number of brain cells. Natural history author Candace Savage writes: “Crows, ravens, magpies, and jays are not just feathered machines, rigidly programmed by their genetics. Instead, they are beings that, within the constraints of their molecular inheritance, make complex decisions and show every sign of enjoying a rich awareness.”

Beyond explaining how and why ravens act as they do, it’s how this innate intelligence manifests itself in behavior that makes these birds fascinating to observe. As seen on NATURE, ravens achieve mastery and possess manipulative powers over other creatures in their domain, often letting others do work for them. For example, ravens will call wolves and coyotes to prospective meals so they can expose the carcass and make the meat accessible to the birds. In addition, ravens will show their true scavenger colors by waiting for other birds with specialized foraging skills to make a catch and then cunningly seize the defeated prey for themselves.

Not all raven behavior is so devilish; some is merely mischievous and even good-natured. On NATURE, we are treated to a raven frolicking in the snow as well as the domesticated pet raven named Loki soothingly and majestically flying alongside her owner’s vehicle. Seeing how affectionate and keen these birds are, it’s easy to understand why one might want to keep a pet raven. As Loki’s owner, Rose Buck, says, “Loki’s bright, clever, very intelligent, and mischievous. Sometimes, he can be an absolute pain, but I wouldn’t be without him. He’s just great.”

Though it might be tempting to run right out to your local pet store to buy a raven, they aren’t available and, more importantly, are federally protected in the United States; it’s illegal to buy or even hold a raven (unless one has a difficult-to-obtain permit). However, many people successfully raise orphaned, nestling crows under 3-4 weeks old to the point where they are able to eat independently, and then release the birds when they are approximately eight weeks old. Information on diet and care of orphaned ravens, as well as a wealth of other material, can be found on the American Society of Crows and Ravens Web site.