American Crow

by Alex Forsythe

Many studies have been done to measure the intelligence of crows. Scientists have found that crows understand the scientific concept of displacement, they can understand analogies, they regularly shape and sharpen tools, and they can describe a human’s face to other crows.

People have been aware of the intelligence of crows for some time. In a fable by Aesop, a thirsty crow wants to get water out of a pitcher. To do this, the crow has to fill the pitcher with rocks until the water level is high enough for the crow to get a drink. Scientists tested that fable recently. They placed food in two tubes, one with a small amount of water and another with sand. Around the tubes, they placed heavy objects, light objects, solid objects and hollow objects. The crow instantly knew to drop heavy solid objects into the tube with water to make the water rise and force the food to the surface. They ignored the tube with sand (the objects would simply cover the food), and they didn’t bother with the light or hollow objects. You can watch the video here: https://www.youtube.com/watch?v=ZerUbHmuY04

Perhaps more impressive, crows can work out simple analogies, such as “bird is to air, as fish is to ___?” When researchers tested the crows on their ability to solve analogies, the crows were able to solve the problems on their first try! In the animal kingdom, only apes have a similar ability as far as we know. You can read about the study here:http://www.scientificamerican.com/article/crows-understand-analogies/

There is a large body of research on the corvids’ ability to design, sharpen and perfect tools. In one experiment, the crow had to take several steps and use several tools to get the food (watch the entertaining video here: https://www.youtube.com/watch?v=JY8-gP3Sw_8). In another, a crow had to bend a wire into a hook to retrieve food from a long tube. (watch the video here: https://www.youtube.com/watch?v=OYZnsO2ZgWo). In the wild, they have been observed making hooks from branches to use to retrieve food. Corvids also use humans as tools. In Japan, crows learned that when the light is red, it is safe to place a nut on the road. When the light turns green, they fly up to watch as the nut is run over and cracked by cars. When the light turns red again, they fly down and retrieve their prize (watch the video here: https://www.youtube.com/watch?v=1P8Nwl7FAJk)

Crows are also very social and they share their knowledge of dangerous predators and places with each other. In one experiment, researchers wearing masks harassed crows around their campus. Two years after the experiment, whenever the researchers were wearing those masks crows would attack them, not only the crows that were involved in the experiment, but additional crows from later generations and other locations. However, when a researcher wore a different mask, the crows would not attack. (http://www.nytimes.com/2008/08/26/science/26crow.html?_r=0). Similarly, crows will recognize good or bad places. In one case in Ontario, hundreds of thousands of crows migrated though one city, and the disgruntled townspeople decided to shoot about 300,000 crows. They only managed to shoot one crow. As soon as they shot the crow, the rest of the crows took flight. Since then, the crows still fly over every year, but they stay just above range of birdshot. (http://www.theglobeandmail.com/life/a-murder-of-crows/article1091590/). Crows also remember the people and creatures that were possible causes of another crow’s death, and they seem to remember the details indefinitely (http://www.sciencedirect.com/science/article/pii/S0003347215003188).

So, should crows be feared for their intelligence? Or admired and respected? That’s up to you, but the next time you think about scaring a crow out of your garden, remember – that crow will NEVER forget your face!