Master of Science (M.Sc.)
John P Swaddle
Bird strike is the often fatal collision between a bird and a surface, such as a window or tower. Collisions kill millions of birds each year in the US alone, and cost industries millions of dollars per year. as more buildings, wind turbines, communication towers and other structures are built, bird strikes and its associated costs are predicted to increase. Researchers have explored mitigative measures to alleviate bird strikes but to date none have solved this growing problem. Recent research suggests that current technologies fail because their design does not take into account birds' sensory ecology, including habituation to loud sounds and some species may lack the ability to effectively see visual deterrents while flying. In this study we explored an acoustic mitigative measure against bird strike. Our goal was to use directional sound as an instrument to warn flying birds of an upcoming visible barrier in their flight path. We hypothesized that when birds experienced a strong sound field (80 dB SPL) in the presence of a visible mist net, they would increase their body and tail angles of attack, enabling them to slow down. Our results show that when flying zebra finches (Taeniopygia guttata) encountered a loud sound field in front of a visible barrier, they slowed their flight (relative to a control flight) by approximately 25% and simultaneously increased their body and tail angles of attack by 25° and 50°, respectively. This alteration of velocity and flight posture will likely increase birds’ capacity to maneuver, due to increased tail drag and improved tail lift, and potentially afford individuals more time to initiate avoidance maneuvers. Collectively, our results support the conclusion that a conspicuous sound can decrease birds’ risk of striking a static surface or object. Our study suggests that emitting sound in front of windows, wind turbines, power lines, as well as cell, radio and communication towers could decrease bird strikes and associated damage and costs.
© The Author
Ingrassia, Nicole, "Does Sound Help Prevent Birds from Flying into Objects?" (2016). Dissertations, Theses, and Masters Projects. William & Mary. Paper 1477068550.