Terre Haute, In. – If you see a green beam of light shooting through the sky in downtown Terre Haute don’t be alarmed. Aliens are not attacking it’s just the next iteration of Crow Deterrent the city is trying. The laser is on the top of the Sycamore building and will shoot toward downtown buildings where crows persistently roost during the winter months. The birds perceive the moving green light as a physical threat, causing them to flee. However, the laser effectiveness is often temporary, timing is crucial, especially at the beginning of the season.