| How | Why |
|---|---|
| Crows can remember any face they see | Scientists tested with face masks that the specific marked crows would screech at some of them when they had the masks on. They would only do that to the ones that were trouble though. The people who were bad when they had masks on were attacked. When they took off the masks, they were ignored. |
| Crows plot with each other | Whenever crows are screeching at each other, they are talking and scheming. As in the previous example, the crows talked to each other about attack on the bad masked scientists. We know this because some of the crows who had not seen the bad scientists still attacked them, so the other crows must have told them too. |
| Memory | As crows were ruining crops, farmers in Ontario killed about half of the 600,000 crows living there, and the rest flew off. After plotting in a barn later discovered, they flew back, but just high enough not to get shot. After that, not one single crow was shot the rest of the year. |
| Crows use tools and can problem solve | One early test of tool use and intelligence in crows had researchers tying a piece of meat to a string, and then tying that string to a stick. The crows all stood on the stick, grabbed the string, dragged it up, held it with their foot, and repeated the action until they could reach the meat. |
| Crows have adaptive behavior. | Crows pay attention to how the human world works, and often use it to their advantage: Some have been observed cracking walnuts by dropping them from the exact height needed to bust them open on the pavement. But in other cases, they take gravity out of the equation and just drop the nuts in front of cars, letting us do the work for them. These same crows also memorize the pattern of traffic lights to optimize the exact moment they drop the nuts, but also to make sure they only retrieve them when the light is red and the crosswalk sign is on, so they don't get run over. If you've ever been out driving, you know the latter is a skill that only about 10 percent of the human population has mastered. |