This unique product uses the hunting calls of sparrow hawks, owls and falcons to frighten other birds away. Tested and proven effective against pigeons, seagulls and smaller birds. Separate settings allow the unit to run constantly or on motion-sensitive (PIR). Timer on constant setting can be set with delays from 5 to 30 minutes. When on motion-sensitive setting the unit is not activated in darkness, when birds are inactive, thus saving power. Mains-powered.