Just read an incredible article in the New York Times. It turns out that crows (and their relatives, ravens and magpies) can recognize human faces. Not only that, they keep a lookout to see if someone they know (and fear) is nearby.
Researchers donned "dangerous" masks, and then trapped, banded, and released birds. They then walked through the same area without the mask: no response. Then they walked through the area with the mask and they were scolded not only by the birds they had trapped but by other birds, who were perhaps taught by the trapped birds that that person was a danger. There's a very illustrative video.
On Wikipedia, they tell about New Caledonian crows who have been studied for their ability to use tools, including human cars: they drop seeds into the roadway and wait for us to crush them!