Which device is primarily used for producing noise to discourage birds?

The propane cannon is a device primarily used to produce loud noises that serve to discourage birds from gathering in certain areas. It operates by igniting a mixture of propane and air, creating a series of loud bangs at timed intervals. This sudden noise can be effective in startling birds and encouraging them to leave the vicinity, helping to protect crops, sports fields, or other areas where birds may cause issues.

Porcupine wire is intended for a different purpose, mainly to prevent animals from roosting or perching on structures, while a screamer may refer to a device that produces a different type of sound or deterrence mechanism, typically more focused on creating distress signals rather than loud bangs. Live traps are used for capturing animals unharmed, rather than for noise deterrents. Thus, the propane cannon stands out as the most appropriate device for producing noise to effectively discourage birds from specific areas.