Accession Number : AD0648967
Title : RED-WINGED BLACKBIRD RESPONSES TO ACOUSTIC STIMULI.
Descriptive Note : Final scientific rept.,
Corporate Author : SANTA RITA TECHNOLOGY INC MENLO PARK CALIF
Personal Author(s) : Boudreau,Gordon W.
Report Date : FEB 1967
Pagination or Media Count : 36
Abstract : A three-month study conducted at Moody Air Force Base, Georgia, revealed that Red-Winged Blackbirds in flight were sensitive to the compressor whine produced by jet engines on the T-37 training aircraft. Response to T-37 sounds was manifested by determined and often spectacular efforts to evade or avoid the sound field. Synthesized versions of the T-37 sounds with carrier frequencies ranging from 2500-3500 hertz, amplitude modulated by frequencies of 75-150 hertz, were more effective than the natural T-37 sounds. No inurement to T-37 sounds developed in the birds. The blackbirds failed to respond consistently to other acoustic stimuli, including other aircraft and their own natural alarm sounds, while in flight. However, natural alarm sounds were effective when projected to blackbirds feeding in fields or perched in trees. Unrelated species present failed to respond to T-37 sounds. Tests using acoustic barrier concepts were successful in re-routing the blackbirds' normal flight patterns and the results suggest this may be feasible in alleviating the bird strike hazard at Moody Air Force Base. (Author)
Descriptors : (*BIRDS, AUDITORY PERCEPTION), RESPONSE(BIOLOGY), AUDITORY SIGNALS, THRESHOLDS(PHYSIOLOGY), HAZARDS, JET ENGINE NOISE
Subject Categories : Anatomy and Physiology
Distribution Statement : APPROVED FOR PUBLIC RELEASE