Sonic sound emitters, are one of the most effective deterrents on the market. Usually consisting of a central unit and several speakers, the system emits distress calls, and, if it is a quality product, calls of predators of the target species as well. Effective emitters randomize pitch, magnitude, time interval and other factors to prevent birds' getting used to them. 

Ultrasonic electronic devices produce high pitch emissions in ultrasound. The sound is designed to be too high pitched for people to hear, but audible to most birds. This has the advantage to preventing disturbance to neighboring households.  

Lasers Bird devices use their Laser beams to seek out birds roosting-spots, alarming and confusing them, causing them to flee. This technological breakthrough is a proven method of bird control for most large commercial areas

All of these units work well indoors and outdoors in: hangars, warehouses, plants, tunnels, loading docks, boat houses, underpasses, storage sheds, barns, sports arenas, convention centers, parking garages and farmers fields.