Evaluating acoustic signals to reduce avian collision risk

Area of Science:

• Ornithology
• Acoustic Ecology
• Bioacoustics

Background:

• Bird collisions with human-made structures cause significant ecological and economic damage.
• Acoustic signals offer a potential method to mitigate bird-structure collisions.
• Signal effectiveness depends on bird sensory ecology, background noise, and sound propagation.

Purpose of the Study:

• To investigate the effectiveness of different acoustic signals in deterring bird collisions.
• To determine if specific sound frequencies and modulation patterns elicit stronger avoidance behaviors.
• To assess the influence of acoustic treatments on bird flight paths near obstacles.

Main Methods:

• Zebra finches were released into a flight corridor with a physical obstacle.
• Birds were exposed to either control conditions (no sound) or one of four acoustic signals.
• Flight behaviors, including distance from hazards and trajectory adjustments, were measured.

Main Results:

• All tested acoustic signals led to birds maintaining greater distances from obstacles and adjusting flight paths earlier.
• No statistically significant differences were found among the various sound treatments.
• A 4-6 kHz frequency-modulated oscillating signal showed a trend towards eliciting the strongest avoidance behaviors.

Conclusions:

• Acoustic signals can serve as effective avian collision deterrents, particularly for solid structures like wind turbines.
• The study highlights the value of behavioral data in assessing collision risk.
• Incorporating acoustic signals into multimodal deterrents is recommended for enhanced bird safety.