Effects of anthropogenic noise on communication in dark-eyed juncos (Junco hyemalis)

Abstract

Noise pollution has numerous consequences for wildlife, including the disruption of acoustic communication through its impacts on signal production, signal transmission, and signal perception. In this thesis, I demonstrated, using complementary correlational and experimental approaches, that dark-eyed juncos (Junco hyemalis) increase the frequency of their songs in response to noise. Next, I broadcasted noise-altered and unaltered songs in noisy and quiet environments and re-recorded them along a 40-m transect, with microphones set up at 1, 5, 15, and 40 m. I measured song degradation along the transect and found that songs degraded predictably with increasing distance, but that recording environment (noisy or quiet), playback environment (noisy or quiet), and the interaction between the two had no effect on song degradation. This indicates that, although juncos increase the minimum frequency of their songs in response to noise, the shift does not, by itself, increase the transmission of the song through noise.