Abstract: An apparatus primarily for bird dispersal purposes at an airport has a remote control means provided for controlling operation of one or more sound emitting devices adapted to cause a detonation or emit a detonation-like sound at a required position or positions, e.g. in relation to an airport runway. The control is such that after a sound emission the device or each device is ready for further operation. Each device may consist of a combustion chamber having an outlet, the remote control means including a timer for initiating admission of fuel such as propane gas into the chamber for a pre-determined period followed by automatic ignition of the fuel/air mixture for detonation thereof. The remote control includes provision for selective operation of the devices at different positions, e.g. adjacent a runway, and also provision for selection of devices for operation at a particular runway in use or at other required locations, i.e., where there is more than one runway or location.