The Bird Barrier Screech Owl Bird Deterrent (sd-owl1) offers an ideal and safe way to keep away birds from damaging your valuable property. This incredible bird deterrent is installed with four predator or frightening audio that effectively deters pest birds from your sites. This includes sounds of birds in trouble, wing hits and predator physical assault cries. The rotating base of the unit mounts easily to any flat surfaces, and spins in the wind. It is only during daylight hours when the photo cell automatically turns the sounds on. The Screech Owl Bird Deterrent is sold one per package.