Anthropogenic noise impairs owl hunting behavior

Emerging evidence indicates that anthropogenic noise has highly detrimental impacts on natural communities; however, the effects of noise on acoustically specialized predators has received less attention. We demonstrate experimentally that natural gas compressor station noise impairs the hunting behavior of northern saw-whet owls (Aegolius acadius). We presented 31 wild-caught owls with prey inside a field-placed flight tent under acoustic conditions found 50-800 m (46-73 dBA) from a compressor station. To assess how noise affected hunting, we postulated two hypotheses. First, hunting deficits might increase with increasing noise-the dose-response hypothesis. Secondly, the noise levels used in this experiment might equally impair hunting, or produce no impact-the threshold hypothesis. Using a model selection framework, we tested these hypotheses for multiple dependent variables-including overall hunting success and each step in the attack sequence (prey detection, strike, and capture). The dose-response hypothesis was supported for overall hunting success, prey detection, and strike behavior. For each decibel increase in noise, the odds of hunting success decreased by 8% (CI 4.5%-11.0%). The odds of prey detection and strike behavior also decreased with increasing noise, falling 11% (CI 7%-16%) and 5% (CI 5%-6%), respectively. These results suggest that unmitigated noise has the potential to decrease habitat suitability for acoustically specialized predators, impacts that can reverberate through ecosystems.