Humans cannot detect these but instead act as a deterrent for the birds that have the ability to register the frequency and can be irritated by it. This is not an effective method for all situations. A free consultation with DRAGONFLY technician will provide you with the information you need to make an educated decision about the type of products you should use to control your bird problems. The decision will be based on the severity of the problem, what the facility is used for and where it is located.