PS 29-146
Shift in songbird vocalizations suggests possible threats of anthropogenic noise for health and fitness
Global change, including increased anthropogenic noise, has been linked to multiple environmental health concerns. Anthropogenic noise has been shown to inhibit songbird communication methods, and therefore overall fitness and reproductive success. To further examine potential impacts of rising anthropogenic noise on ecological health, we examined how songbirds adjust their communication in the presence of various levels of traffic noise. To do so, we conducted an acoustic analysis of Brown-headed Nuthatch (Sitta pusilla) and Eastern Towhee (Pipilo erythrophthalmus) vocalizations at 41 sites in upstate South Carolina with varying levels of traffic noise. With frequency data on the vocalizations we were able to test for differences among vocalizations with regard to traffic noise.
Results/Conclusions
Our data demonstrate that even moderate levels of noise alter the structure of avian vocalizations. In particular, the bottom of Brown-headed Nuthatch vocalizations shifted upward to avoid overlap with the increased ambient noise associated with vehicular traffic. Eastern Towhee bottom of vocalizations display the same shift, though only in the final 'tea' component of their call. Vocalization adjustment to overcome acoustic masking reduces reproduction and survival and the effects of noise pollution on inter-species reactions are only now being identified. Understanding the impacts of anthropogenic noise on bird health provides insight into ecosystem health. Thus it is essential that we understand the impact of this noise pollution and implement effective and efficient conservation strategies to protect global ecosystem health.