• Use of broadcasts of pre-recorded distress, warning or alarm calls to disperse a single species, or closely related species, from the immediate area of the broadcast. 

(D135.3.w3, D160.App3.w11,  D210.4.w4)

• The BirdGard^® device is programmable with up to four alarm or guard calls. 
  • Intervals between broadcasts can be randomised.
  • A particular programmed call can be turned off or on as desired. 
  • Uses a 12 volt battery; a solar powered version is available.
  • A version with up to 20 speakers is available.
  • A marine version is available with calls of various gulls plus cormorants.

  (D211.AppIIIc.w12)

• For use on large flocks of the appropriate species. (D135.3.w3)
• Effective on gulls and some herons. (D10)

• Generally less effective on individuals or small flocks than on large flocks. (D135.3.w3, D160.App3.w11)
• Effective at relatively low sound intensities. (D160.App3.w11)
• Relatively slow habituation. (D10, D160.App3.w11)
• Effectiveness may be increased by using together with pyrotechnics. (D135.3.w3)

• Highly species-specific. (D10, D160.App3.w11)
  • For gulls, sounds of one species may also affect other gull species. (D211.AppIIIc.w12)
• Birds may be attracted rather than driven away. (D160.App3.w11)
• Predators and scavengers may be attracted. (D160.App3.w11)
• Habituation may be rapid in some species (e.g. herons). (D210.4.w4)
• May be ineffective with some species. (D210.4.w4)

• Tape players or other appropriate broadcasting equipment.
• Recorded distress, warning or alarm calls.
• BirdGard^® units plus 12 volt batterries and other additional equipment as required.

• Tapes of the distress/warning/alarm calls of the appropriate species may not always be available.
• BirdGard^® units may not be available and may or may not have the correct calls available. (D211.AppIIIc.w12)

• Birds may be attracted rather than driven away. (D160.App3.w11)
• Predators and scavengers may be attracted. (D160.App3.w11)