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ELECTRONIC BROADCAST CALL UNIT FOR BIRD CONTROL IN ORCHARDS
Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.orgCitation: Applied Engineering in Agriculture. 21(4): 721-727. (doi: 10.13031/2013.18559) @2005
Authors: M. J. Delwiche, A. P. Houk, W. P. Gorenzel, T. P. Salmon
Keywords: Alarm call, Almonds, American crow, Biosonics, Bird control, Bird damage, Corvus brachyrhynchos, Distress call
Birds can cause significant damage to a number of agricultural crops. Past studies have shown that alarm and
distress calls are useful tools for repelling birds from agricultural and industrial settings, and current electronics have made
this technique easier to use. A new study focused on integrating broadcast distress calls into bird management programs
required the design of broadcast units with emphasis on low cost, preventing habituation, and saving power. The circuit was
built around a sound recording integrated circuit with 120 s of nonvolatile memory and was set to play four 25-s distress calls,
wait approximately 12 min between calls, and switch to a new call after a user-selectable number of call events (256 used
in the field tests, corresponding to 3 - 4 days). An analog timer was used to set the call/wait cycle and call switching was
achieved with a ripple counter. To save power, the circuit turned off every night using a voltage divider with a photoresistor
to drive a power MOSFET switch. An audio-integrated circuit was used to amplify the sound signal, which was played through
a trumpet speaker. Power consumption was low enough to allow operation from a 36-Ah hour battery for 2.5 months without