During his talk Joshua Klein mentions a University of Washington study on crows. So I proceeded to look this up even though I distinctly remember listening to a show on NPR about crows. Professor Marzluff asked his students to wear a caveman mask whenever they tagged the crows. Why would he do that you ask? Well, because once, when someone was trying to get rid of a crow near their home they were forever cawed by the crows in the neighborhood and pretty soon it caught on and even crows that weren't in the neighborhood recognized him. So Marzluff performed the experiment and proved that crows recognized the caveman mask even when it was upside down.
So next time you think about killing a crow think about this two distinct stories about crows.