Breeding ecology of birds in pinon-juniper woodlands and the influence of gas well compressor noise

Noise pollution generated by human activities is omnipresent and despite its enormous spatial footprint, its influence on natural communities is poorly understood. Previous attempts to determine the influence of noise on wildlife have found that habitat fragmentation associated with noise confounds its effects on communities, thereby limiting researchers' ability to distinguish whether noise or another confounding variable were responsible for observed trends. In this study, the extraction of natural gas within pinon ( Pinus edulis)-juniper (Juniperus osteosperma) woodlands of northwest New Mexico provided a system in which to isolate noise as an experimental variable to determine its effects on nest density, nest site selection, and nest success of breeding birds. Additionally, in order to gauge any effects of the noise disturbance on the nesting community, we gathered valuable life history information on the little known members of the pinon-juniper avian community.; We found a previously unrecognized importance of juniper to nesting birds. Birds selected junipers for nest trees significantly more than expected from the pinon-juniper ratio. High nest density sites also had a significantly higher proportion of juniper to pinon than low nest density sites. We recommend maintaining natural pinon-juniper ratios in management activities.; Noise levels through 400 m from compressors on treatment sites were significantly higher than those recorded on control sites, impacting an estimated 50.2 ha surrounding each compressor. No differences in nest densities existed between treatment (noisy) sites and control sites among the avian community as a whole. However, Black-chinned Hummingbird (Archilochus alexandri) and House Finch (Carpodacus mexicanus) demonstrated a preference for nesting on noisy treatment sites. Number of Chipping Sparrow ( Spizella passerina) nests did not differ on treatment and control sites. Brown-headed Cowbirds (Malothrus ater) parasitized Chipping Sparrow nests significantly more on control sites than treatment sites. For nests of all three species, nests experienced lower predation and no parasitism when exposed to higher noise levels. Noise pollution appears to not only influence the nesting patterns of birds common to pinon-juniper woodlands, thereby altering the avian community, but also to influence nest success through changes to predation and parasitism patterns.