Impact of chronic noise exposure on antipredator behavior: an experiment in breeding house sparrows

Over the last century, expanding urbanization has led to a strong increase in the levels of background noise. This noise pollution has been shown to negatively affect wildlife (e.g., reduced species diversity and density, reduced breeding success), especially birds. Most research addressing the effects of anthropogenic noise has focused on avian communication and, to date, very little is known regarding the impact of chronic noise exposure on nonvocal behavior such as antipredator behavior. Here, we exposed free-living house sparrows (Passer domesticus) breeding in nest-boxes to either a playback of traffic noise (disturbed birds) or the rural background noise of the study site (no playback: control birds) during their first breeding attempt. We tested whether one of the female’s antipredator behaviors (i.e., flushing distance) was affected by exposure to chronic noise and investigated the impact of chronic noise on reproductive performances. Disturbed females flushed more rapidly than controls, suggesting that birds may compensate for reduced ability to detect predators with increased vigilance. However, we found no significant effect of exposure to chronic noise on reproductive performances. Our findings show, for the first time, that chronic noise exposure can affect the antipredator behavior of a breeding bird.