AnComm Final 2

This paper was focused on the effects of anthropogenic noise, urban structure, and vegetation on the trills of chipping sparrows. Chipping sparrows evolved in an open habitat, thus an urban environment generates neoteric selection pressures on their song. The researchers aimed to answer three major questions: (1) whether individuals with different song variants generated novel solutions to noise and reverberation; (2) how the opposing forces of background noise and highly reflective structures affect song; and (3) the effects of noise and structures on trills and subsequently, vocal performance. Their predictions hinged on splitting males into two groups. Group 1 was composed of males that had lower minimum frequencies, higher maximum frequencies, broader bandwidths, and lower trill rates than group 2 males. They predicted that group 1 males would sing at a higher and narrower frequency band but would not change their trill rate. Whereas they predicted that group 2 males would decrease trill rate, but wouldn’t change their trill frequency. Lastly, they predicted that noise would have a greater affect on frequency, that structure would have greater affect on song timing, and that vocal performance would decrease with increasing noise and structure.