Motion Sensing Crow, w/ Red Eyes.. Scary Halloween Sensor Prank (Pack of 2) Spooky Crows let you know when someone is approaching! Each creepy plastic crow stands 3" tall and has a motion sensor that activates the crow's "Kaaaaw" sound when any motion is detected nearby. Each is perched upon a metal clip that makes displaying them a breeze. Perfect for haunted houses, Halloween decorations, and startling your siblings.