Abstract:

Anthropogenic noise has been implicated as a cause of declines in avian species diversity and densities; however, these patterns are not conclusive because noise has not been uncoupled from potential confounding variables that accompany noisy human a ctivities. During the summers of 2005–2007, noise was isolated through the use of natural gas wells with and without noisy compressors (treatment and control sites, respectively). No difference in overall nest density on plots with and without compressors was found; however, noise significantly reduced nesting species richness. Individual species also demonstrated responses to noise: Mourning Dove nests were more abundant on control sites, whereas Black-chinned Hummingbird and House Finch nests were more abundant on treatment sites. Several species were also found to nest significantly farther from well pads on treatment sites than on control sites. Nest success was higher on treatment sites than on control sites, due to lower levels of predation. In areas influenced by anthropogenic noise, predators may be present, but unable to locate nests, or they are in lower densities or absent. Anthropogenic noise appears not only to influence avian nesting patterns, thereby altering the avian community, but also to influence nest success through changes to predation patterns.