Oil development in the Bakken shale region has increased rapidly as a result of new technologies and strongdemand for fossil fuel. This region also supports a particularly high density and diversity of grassland bird species,which are declining across North America. We examined grassland bird response to unconventional oilextraction sites (i.e. developed with hydraulic fracturing and horizontal drilling techniques) and associatedroads in North Dakota. Our goal was to quantify the amount of habitat that was indirectly degraded by oil development,as evidenced by patterns of avoidance by birds. Grassland birds avoided areas within 150 m of roads(95% CI: 87–214 m), 267 m of single-bore well pads (95% CI: 157–378 m), and 150 m of multi-bore well pads(95% CI: 67–233 m). Individual species demonstrated variable tolerance of well pads. Clay-colored sparrows(Spizella pallida) were tolerant of oil-related infrastructure, whereas Sprague’s pipit (Anthus spragueii) avoidedareas within 350 m (95% CI: 215–485 m) of single-bore well pads. Given these density patterns around oilwells, the potential footprint of any individual oil well, and oil development across the region, is greatly multipliedfor sensitive species. Efforts to reduce new road construction, concentrate wells along developed corridors,combine numerous wells on multi-bore pads rather than build many single-bore wells, and to place well padsnear existing roads will serve to minimize loss of suitable habitat for birds. Quantifying environmental degradationcaused by oil development is a critical step in understanding how to better mitigate harm to wildlifepopulations.
