Types

• There is a wide range of sound deterrents to choose from, including sonic, bio-acoustic and even ultrasonic. Each deterrent will work under certain situations. The effectiveness depends upon a variety of factors, including the particular type of bird that is being deterred.
  
  

Effectiveness

• Sonic deterrents work well when first installed. However, as the birds grow accustomed to their presence and the sound they emit, their effectiveness diminishes. If the sonic deterrents are moved around frequently, the birds will tend to temporarily flee from their presence. Ultrasonic deterrents emit frequencies that will not be heard by humans, but will only work on certain species of birds. Bio-acoustic deterrents rely upon simulating the cries of both predator birds and the alarm signals of many species, causing the birds to vacate the area.
  
  

Location

• Mona Zemsky of Bird-X Inc., a company based in Chicago that has been practicing nondeadly bird control since 1964, reports that the key to deterring birds is to make the areas where the birds would normally congregate undesirable. Placing the sound deterrents near the areas where birds want to nest and roost will help to create an atmosphere that will be unpleasant for them.
  
  

Randomness

• According to Denton Gilliam of Noah's Ark Pet Store, sound deterrents work well when they are set up at random times: "If you always set off the sound system at the same time, the birds figure out that it's not something they need to worry about. You need to make sure that you switch things around."
  
  

Combining Deterrents

• The effectiveness of sound deterrents is enhanced by using them in conjunction with other deterrents, such as visual deterrents and physical barriers. By combining deterrents, the odds are increased that birds will eventually seek somewhere less antagonistic toward them and move on.