http://www.vpr.net/audio/programs/232/2013/03/130302-Crows-Recognize-Individual-Faces.mp3
To find out if they could recognize an individual human face, Professor John Marzluff of the University of Washington wore a mask while trapping, banding, and then releasing seven American Crows on campus.
Later, he walked through the campus wearing the mask.
A big group of birds scolded and dive-bombed him.
He thinks it's a benefit to the birds' survival to point out and recognize challenges in their environment.
Watch a video and learn more at ScienceMag.org!