The Response of Songbirds to the Seismic Compression Waves Preceding Sonic Booms.
Abstract:
Among the environmental and operational problems studied during the program were the effects of the sonic booms on wildlife. In addition to the customary sonic boom overpressure signature measurements, audio tape recordings were made at both outdoor and indoor measurement sites and these were studied in realtion to the other measures obtained. Analysis of the audio tapes disclosed an interesting phenomena. The continuous songs of birds of the field were completely silenced 4 to 8 seconds prior to the arrival of the audible sonic boom. Additional audio recordings, made for the specific purpose of verifying this complete silence of all songbirds 4 to 8 seconds prior to the arrival of the sonic booms audible report and overpressure signature measurement, were identical to the first obtained. Further study disclosed that this response of songbirds coincides with the arrival of the seismic signal propagated through the ground and preceding the sonic boom shock wave by 4 to 8 seconds. Modified author abstract