You may recall a prior post in which I talked about how intelligent crows are. In fact, there was a special on PBS demonstrating their ability to solve problems and even recognize human faces (HIGHLY recommended if you haven't yet had a chance to see it):
In a more recent study, Dr. Marzluff and colleagues used brain scans to demonstrate that crows not only remember faces, but they can also remember how they were treated by various people. In the study, his team captured 12 wild American crows while wearing latex "captor" face masks. In captivity, the caretakers wore different latex masks. What they discovered using brain imaging was that after 4 weeks of captivity, areas of the brain associated with motivation and reward showed activity in response to seeing a caretaker, whereas areas associated with fear were active upon seeing the captor.
I suppose cutting down their favorite tree in our front yard (it was pulling up the driveway and foundation) explains the poop on my car.
Marzluff JM, Miyaoka R, Minoshima S, Cross DJ. Brain imaging reveals neuronal circuitry underlying the crow’s perception of human faces. epub ahead of print. Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1206109109
A young magpie that frequents my lawn had a string tangling it's foot. I captured the bird, removed the string and then released it. For several weeks afterwards whenever it saw me it swooped and pecked the back of my head. Now, when I dig, the bird is inches from my shovel. The bird ignores everyone else.