NOVEL ACOUSTIC ENVIRONMENTS COMPROMISE SONG PERFORMANCE IN CHIPPING SPARROWS

Benjamin M Davidson; California Polytechnic State University, San Luis Obispo; bjdavids@calpoly.edu; Clinton, D, Francis

Anthropogenic noise has been shown to have substantial effects on avifauna structures and avian vocalization behaviors. Additionally, the performance tradeoff for many songbirds between song length and bandwidth has been extensively documented in the presence of anthropogenic noise. Here we quantified the effects of novel acoustic environments on song performance through quantile regression analyses and quantifying a performance frontier. Chipping sparrow songs were recorded in RCHMA of northern New Mexico in spring of 2009 in areas of anthropogenic noise of natural-gas-well compressors, and in acoustically unaffected areas. Additional data from Xeno-Canto and Podos et al. (1997) was included to provide a more robust and diverse data set for the quantile regression analyses. The quantile regression analysis provided a fitness frontier based on syllables in songs and bandwidth of the song. The best performers were found along the frontier, while the worst performers were found well below the frontier. We analyzed distances of individuals from the frontier, only for the birds we had recorded in RCHMA, and found that individuals found near gas-well compressors were significantly further below the performance frontier. This indicates that beyond avifauna structuring and shifting singing behaviors, anthropogenic noise has a significant effect on song performance.

Ecology and Conservation of Birds     Student Paper