A Murder of Crows

Jadiel Wasson

Originally published October 31, 2014

Photo by: Kristen Thomas and Jadiel Wasson

Photo by: Kristen Thomas and Jadiel Wasson

In the spirit of Halloween, this is a tale of fiction shrouded in fact: A slight exaggeration of the natural ability of the magnificent family of birds known collectively as the Corvidae family.

Imagine this: You are walking alone in the park on a foggy morning with only the pale morning sun to guide you. *Caww*  What was that? *Swoosh.*  Something lands on your bag. You swing it in an attempt to thwart the menacing perpetrator. You move to investigate the damage and realize it is only a crow with a piece of your bagel in its mouth. Your sigh of relief is stifled with the thickening of the air with sounds like the fluttering of thousands of bird wings. A murder of crows has been incited. You immediately make your exit and run to work, afraid of what you have started.

You may have escaped the peril. But what you do not know is that the crows will remember your face.

Crows have an unparalleled ability to recognize and remember faces. To test this ability, a Seattle group of scientists captured and tagged crows while wearing a variety of different masks. Two years later, the crows were able to recognize the masks and remember the misdeeds of the researchers leading to harassment and admonishment of the researchers. This ability to create a negative association with certain people and their behaviors was traced to a particular brain region by another group of researchers. They also observe differential brain regions becoming activated as crows processed human faces. These studies reveal how crows can integrate memory and perception to adapt accordingly to their surroundings.

That night, you are walking home from work, forgetful of your early morning transgression. *Squawk! Squawk!* It begins with one. Then like an avalanche, all of the crows join in a chorus of horror. They dive bomb as only angry birds can. *Crack* You’ve just been hit with a massive object… was that a weaponized nut? It is almost as if the crow who threw it knew what angle and height to drop it from to incur the most damage.



In fact, it has been well documented that crows can calculate the height and velocity it takes to crack a nut with the least possible damage to the treasure inside. They are even able to deduce environmental clues as once the nut has been dropped on the street, they have the cognizance to wait for traffic to stop in order to jump into the street and collect the spoils. This cold calculation also extends to food storage. Crows, like few other animals, store food away for future use but take it two steps further. In a series of studies analyzing the ability of crows to adjust storage tactics, crows demonstrated not only an ability to deceptively hide food from thieving on-lookers with a “slight of hand” stratagem, they also altered food storage times to account for perishability of food.  These behaviors demonstrate predictive and causal thinking, signs of higher cognition.

Once the crows start using heavy artillery, you realized how much danger you really are in. You sprint home and lock the doors. From your balcony window, you can see that they have tracked you down. They appear to be fashioning small tools from the barbed succulents outside of your apartment, all in the same manner with the same directional tendency.

The ‘handedness’ of crows has been documented to be not only at the individual level but also appears to exist at the social/cultural level in crow species. It hints to brain laterality where there is a division of labor between the two hemispheres, leading to the ability to coordinate actions. It is also important to note that crows do in fact have “cultural” behaviors as it has been documented that crows talk to each in regional dialects.  

Stepped tool making, which has mostly been observed in primates, has been well documented in crows, highlighting their high cognitive function. Studies show that not only can crows decipher which tools would be the most appropriate to complete a specific task (i.e. . choosing proper diameter and length of a stick to retrieve food), they also have the ability to generate these tools. Crows have been documented to independently generate tools in order to complete specific artificial tasks that would not be encountered in the wild. Imagination is considered one of the hallmarks of high cognitive function.

What are they going to do with these barbed tools? The thought is maddening as they fly up towards your balcony window and realize you pet tarantula has been left out for air. As they spear your beloved pet before your eyes, you begin to realize this probably will not end well. They begin to pick the lock to gain access to your apartment. Why are they so smart?

In fact, crows do in fact use small spear-like tools in the wild to forage for insects along the forest floor. Small hook shaped tools are used to gather larvae from trees.

Based on brain to body size ratio, crows have a brain capacity on par with non-human primates. Structurally, their brains are very different while functionally there are certain areas of their brains that are analogous to primates. The region of the brain that is responsible for cognition is enlarged in the Corvidae family compared to other birds. They share the four basic hallmarks of cognition with apes: imagination, flexible knowledge and learning ability, causal learning and prospection. Granted, they cannot pick a lock, but they do have the ability to generalize knowledge and apply what they have previously learned to a novel situation. This allows them to be highly adaptive animals, which is a large reason for their success in urban areas.

*Click* The lock has been picked. The last thing you hear: the fluttering of wings. Who knew how intelligent a bird could be?

What makes crows an interesting paradigm in evolutionary history is that their intelligence is an extreme example of parallel evolution.  Crows have diverged on the evolutionary tree over 100 million years, and as a result have very differently structured brains compared to mammals. Mammals were thought to be the only animals that can possess high cognitive function, thus leading to the idea that their brain structure conferred this ability. Despite the large differences in brain structure, crows are becoming recognized as being just as intelligent as primates. Ultimately, crows represent a great model for how intelligence and cognition can evolve independently throughout evolution.