What is "flock!"

Flock! (stylized as FLOCK!) is a puzzle video game developed by Proper Games and published by Capcom for Windows, PlayStation Network and Xbox Live Arcade. It was released for Microsoft Windows on April 7, 2009 through Steam and Stardock's digital distribution service Impulse, Xbox Live Arcade on April 8, 2009 and PlayStation Network on April 9, 2009.