Wind turbine noise pollution reduces songbird vocal presence through changes in abundance

Wind turbines add to global environmental pollution through prominent noise emissions, yet significant gaps remain in our understanding of the adverse effects of this noise on wildlife. In this study, we investigated the impact of this noise on the acoustic environment and songbird behavior by employing a unique "phantom wind turbine" method: broadcasting wind turbine noise in a natural habitat and monitoring the area before, during, and after the noise treatment. Specifically, we recorded calls and abundance of the Sardinian warbler, Curruca melanocephala momus. Our results reveal a significant reduction of 25% in the mean number of calls in the area, and 43% in mean bird abundance during the wind turbine noise treatment compared to before it. Controlling for abundance, we found no significant impact on calling effort per capita. Moreover, we found a 63% reduction in the probability of vocal presence at the heart of the noise-polluted area compared to the peripheries. However, once calls were present, their number was seemingly unaffected by sound level. We conclude that the reduction in bird abundance alters the acoustic environment without evidence of a direct change in warbler vocal activity. Our study highlights the need to consider noise pollution's ecological impacts when developing wind energy infrastructure to ensure sustainable development and protect declining songbird populations.