US Patent 7227452 Apparatus to deter birds with ultrasound

Birds carry many parasites and other diseases, which pose a health risk to humans which come into contact with their habitat. However, ultrasonic waves agitate and deter birds and other pests from roosting in nearby areas. The disclosed device utilizes solar energy to power a battery pack, which in turn activates both a tone generator and its adjoining amplifier to create and emit the annoying ultrasound. In this way, birds are dissuaded from gathering in particular areas where the ultrasonic device is in use, and humans are provided a more healthy and disease-free environment.