After two years of carefully observing ravens in the wild, researchers at Germany's Max Planck Institute for Ornithology and the University of Vienna in Austria conclude that, similar to humans' use of hand gestures, ravens use their beaks and wings to communicate.

http://www.scientificamerican.com/article.cfm?id=ravens-use-hand-gestures
http://www.science20.com/curious_cub/ravens_gesture-85095