Bird Brains: A Summary of Corvid Intelligence

Stephanie Guo | Assistant Editor

Corvids, or the family of birds that includes such species as crows, ravens, magpies, and jays, are ubiquitous in our towns and cities. On any given day in Austin, you might be able to hear the piercing screeches of blue jays or the harsh caws of American crows (not to be confused with grackles, which are part of an entirely different bird family and can be distinguished from corvids by their bright yellow eyes). If you’re especially lucky, you may even see a raven flying overhead. Opinions on these birds, most notably crows, range from regarding them as a nuisance that should be eliminated, to loving them enough to create entire blogs dedicated to them, to writing about them in an article for The Pioneer.

No matter what you believe about corvids, one thing that’s true is that they’ve been proven to have exceptionally high intelligence. Researchers have traditionally assumed that birds operate entirely on instinct and cannot perform higher cognitive functions hence the insult, “bird-brain.” However, today the general consensus seems to be that birds are intelligent in their own right. In fact, corvids may even rival non-human primates in their intelligence. Corvids are among the most intelligent birds discovered by humans, sharing this spot with parrots which are known to have the ability to gain an understanding of human language and use words correctly and creatively.

One way corvids demonstrate their intelligence is through their ability to use tools. According to a 1996 study conducted by researcher Gavin R. Hunt, New Caledonian crows can make hooked tools out of plant matter to forage for food. These crows are the only non-human animal species to be recorded for their ability to manufacture hooked tools. Tool use is a behavior typically associated with complex cognition, so the crows’ ability to not only use, but also create unique tools is a testament to their high intelligence. 

Corvids may also understand the principle of cause-and-effect. New Caledonian crows have a basic understanding of water displacement, as shown in a 2014 study where the crows were presented with various tubes of water with food floating just out of reach and a selection of different stones and weights. They were tasked with using the stones to raise the water level and retrieve the food. The crows were able to perform these tasks at the same level of an average 5-7 year old human child. Their success at completing some of these tasks demonstrates that crows have knowledge of causality and are likely not just acting on instinct and conditioning, contrary to what biologists formerly believed.

Certain species of corvids, including American crows, are also able to remember the faces of humans who have either antagonized them or cared for them. Some people have used this ability to their advantage, forming relationships with crows through regular feeding routines. With time, the crows may begin to associate these people with food and visit them daily; one girl in Seattle has allegedly received various trinkets from the crows she feeds which she regards as gifts. On the other hand, one can earn the ire of crows by attempting to harm them, and some have reported being systematically attacked by crows for months after only a single incident of crow endangerment. Several anecdotal reports show corvids’ ability to memorize faces; this phenomenon is also backed by multiple studies. Dr. John Marzluff, a professor at the University of Washington and a well-known researcher of corvid intelligence, has written extensively on corvids’ facial recognition ability in research articles and books such as Gifts of the Crow. A study he conducted with Heather N. Cornell and Shannon Pecoraro in 2011 demonstrated that American crows were able to communicate information about dangerous people to both other members of their species and to their offspring. The recipients of this information learn to react negatively to those people even if they haven’t seen them before. Overall, these findings show that crows routinely engage in advanced communication and social learning. 

These birds’ facial recognition skills may also extend to themselves. In a 2008 study, one species of corvid, the Eurasian magpie, was found to be able to recognize itself in a mirror a test that is commonly used to measure self-awareness in animals. In the classic version of the test, the subject has a mark placed on their body, and then they are placed in front of a mirror. If the subject attempts to examine the mark on their body upon seeing it in the mirror, they are said to possess self-recognition. As of today, the Eurasian magpie is the only bird that has officially passed the mirror test. Notably,  there may be several issues with the validity of the mirror test. There is a high-risk for false negatives because many animals may not rely solely on physical appearance for recognition or simply don’t care enough about marks on their bodies to examine them. Therefore, failing the test doesn’t mean the animal completely lacks self-awareness. However, passing the test is a valid way to demonstrate self-awareness, showing that the Eurasian magpie can visually distinguish between itself and others.

These discoveries only encompass a fraction of the complexity of corvid behavior. Many studies have been conducted on corvid intelligence, with more to come. Additionally, outside of empirical findings, corvid enthusiasts have countless stories about their personal interactions with these enigmatic birds. Multiple people have apparently observed phenomena such as crows standing vigil over their dead in a sort of funeral, making artistic gifts for those who feed them, and ravens playing in the snow, among many other accounts. Now that researchers have shown more of an appreciation for avian intelligence, we may quickly become closer to solving the mysteries behind corvid behavior.

As for me, I’m going to keep trying to win over the crows in my neighborhood with my five-pound bag of peanuts.

(By the way, if you’re interested in the water displacement study, YouTube has a video with some footage from the experiment here!)

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