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Copyright of Conservation Biology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Avian Conservation & Ecology is the property of Resilience Alliance and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Western North America's grasslands have undergone a rapid expansion of conventional oil and natural gas development, the effects of which are largely unknown for nesting songbirds. Understanding mechanisms that drive ecological responses to infrastructure is essential for our ability to identify and minimize potential negative effects on wildlife. Our study sought to distinguish between effects driven by physical structures and those driven by associated anthropogenic noise. Further, we evaluated whether some structure types have smaller ecological footprints than others. We monitored 747 grassland songbird nests, of five species, in Alberta's mixed-grass prairie to determine if, and why, the presence of infrastructure affects nesting success. Nesting success was significantly lower at infrastructure sites relative to controls for both Savannah sparrow ( Passerculus sandwichensis ) and vesper sparrow ( Pooecetes gramineus ), as well as at screwpump relative to pumpjack oil wells. There was no correlation between nesting success and noise intensity, and nesting success was not significantly lower near roads. However, nesting success was lower at electric grid-powered sites relative to generator-powered sites, suggesting that power distribution lines may benefit some nest predators. Vesper sparrow nest density increased with proximity to oil wells and compressor stations, so it is possible that these sites are ecological traps for this species. Management strategies focusing only on reduction of anthropogenic noise and disturbance may be ineffectual for conservation of grassland songbirds. Managers should also seek to reduce the physical footprint of infrastructure on the landscape, replace screwpumps with pumpjacks, and replace grid powered with generator-powered wells. [ABSTRACT FROM AUTHOR]

The rapid expansion of oil and natural gas development across the Northern Great Plains has contributed to habitat fragmentation, which may facilitate brood parasitism of ground-nesting grassland songbird nests by brown-headed cowbirds ( Molothrus ater ), an obligate brood parasite, through the introduction of perches and anthropogenic edges. We tested this hypothesis by measuring brown-headed cowbird relative abundance and brood parasitism rates of Savannah sparrow ( Passerculus sandwichensis ) nests in relation to the presence of infrastructure features and proximity to potential perches and edge habitat. The presence of oil and natural gas infrastructure increased brown-headed cowbird relative abundance by a magnitude of four times, which resulted in four times greater brood parasitism rates at infrastructure sites. While the presence of infrastructure and the proximity to roads were influential in predicting brood parasitism rates, the proximity of perch sites was not. This suggests that brood parasitism associated with oil and natural gas infrastructure may result in additional pressures that reduce productivity of this declining grassland songbird., Competing Interests: We have no competing interests to state.