Auditory bird deterrents take advantage of most birds’ (and other animals) take flight response to sudden loud noises, predator “voices” and calls of birds in distress. Upon hearing one of these noises, a bird in flight will divert its path away from the area while a bird not in flight will take flight to flee. Auditory bird scare devices can be effective if used appropriately. As with other deterrents (physical, chemical and visual), auditory scare tactics should be used on an infrequent basis and be targeted at bird feeding, roosting and nesting times. They should also be moved around within the area where they are needed to reduce the likelihood that the bird pests become habituated or accustomed to the deterrents.
Propane or LP gas cannons have been widely used in agricultural bird scare settings. Earlier models were purely mechanical and offered a blast resembling a gunshot at regular intervals. More modern electronically controlled scare cannons can be set via a timer to sound off at irregular intervals at specific times of the day, reducing habituation.
Propane scare cannons function by metering a small amount of gas (the same as is used in backyard gas grills) into a tube that serves as an ignition chamber for the gas which explodes, emitting a loud bang. Sometimes referred to as bird bangers or bird cannons, they are also widely used in airport bird control. Propane cannons are quite controversial in rural areas when they are used with neighbors nearby. Care MUST be taken to use them only when necessary (planting and harvesting times), like when corps are ripening. Nobody wants to hear a cannon going off for months at a time, around the clock. Be sure to use a timing mechanism to turn off the cannon at night.
Noisemakers such as pyrotechnics and firecrackers are commonly used in bird dispersal, especially in urban settings and on farms. These are basically just like fireworks used for Independence Day celebrations. They are loud, scream, flash and bang. Be sure to be considerate of neighbors and obtain any necessary permits for use. These work on the same sudden scare principal as propane cannons. They can be effective at dispersing birds from nesting and roosting sites although a consistent and persistent plan for use must be in place to be effective any more than a few days.
There are ultrasonic (not audible to humans) devices that emit wavelengths of sound that are irritating to birds. Although not much research has been conducted into the effectiveness of ultrasonic deterrents, some believe they are effective at scaring birds of some types.
Distress calls and alarm calls are frequently used to frighten birds away. An electronic system emits sounds of birds in distress or predator noises. These noises incite a “flight” response from birds and repel them from the area. Birds associate such sounds with danger and make an effort to avoid the area. These bird scare devices are sometimes referred to as tweeters or squawkers. As with propane cannons, they are sometimes controversial as they also annoy humans, especially when over used or when used on a routine (every 10 minutes) or continuous basis. Distress and alarm calls have been used effectively in a variety of situations ranging from dispersing crow roost sites to goose control.
The DIY pie pan garden bird control device is also an auditory deterrent. It is easily constructed and implemented. In addition, it offers a visual deterrent effect as well.
Auditory bird deterrents can be very effective in bird pest control. They must be used appropriately and with variability to prevent habituation. Also keep neighbors, both residential and business, in mind when utilizing audible deterrents. They can be irritating to humans as well.