Scarecrows

Birds are smart!:

John Marzluff, of the University of Washington in Seattle, wanted to prove his gut feeling that the crows he studied could identify individual human faces. So he and his students brought out some props. They donned a series of Halloween masks—one was a caveman, which the scientists wore when they trapped the birds. They then let the birds see them in “neutral” masks, like one resembling Vice President Dick Cheney (though this is probably one of the few times Cheney has been referred to as “neutral”).

Sure enough, when the researchers later went for strolls around campus, the crows “scolded” someone wearing the caveman mask, and continued to do so two years into the study. The same scientists and volunteers wearing Dick Cheney masks or other “neutral” faces didn’t hear nearly as much abuse from the crows, though they probably earned a lot of confused looks from passers-by.