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Environmental Consequences of the Proposed Action: <br />Direct and Indirect Effects: As proposed, construction and drilling activities are scheduled to <br />take place during the late summer and fall months and would not typically coincide with <br />migratory bird nesting activities. <br />In the event drilling activities were to extend into the nesting season there would be worst -case <br />potential to clear shrubland nest habitat at the rate of about 7 acres per year (failing an average of <br />2 -3 nesting attempts per year) and temporarily disturb nest activity across an additional 140 acres <br />of nest habitat adjacent to disturbance (average of 14 acres for 3 -7 days at any given time). <br />Indirect disturbance of nest habitat in close proximity to infrastructure would be capable of <br />failing attempts (e.g., average of 5 acres per site with potential failure of 15 -20 attempts per year) <br />or, depending on circumstances, result in occasional nest failure where brief disruptions occur <br />out to 300 feet from activity (e.g., prolonged absence of adults during inclement weather). This <br />influence may extend to an average of 9 additional acres per site, with potential failure of up to <br />10 nests per year. Although many of the species encountered during these activities would be <br />generalists such as western meadowlark, blue -gray gnatcatcher, chipping, lark, and vesper <br />sparrows, due to the prevalence of, particularly, Brewer's sparrows in these shrublands, birds of <br />higher conservation concern may comprise 30 -50 percent of affected nests (worst case, about 12 <br />per year). Worst case effects, though unlikely, would have no measurable influence on the <br />abundance or distribution of breeding populations of migratory bird even at the smallest <br />landscape scale. <br />Dispersed, small -scale habitat modifications represented by reclaimed areas cleared of shrubs <br />and occasional, brief monitoring activity would have little, if any, subsequent influence on the <br />pre- development distribution, abundance, or productivity of migratory birds inhabiting the <br />individual facility locales. <br />Cumulative Effects: Leasing and development of the Red Wash Tract would contribute <br />incrementally to those surface uses that occupy and adversely modify lower elevation shrubland <br />and woodland habitat suited for nesting use by migratory birds, particularly those species that are <br />considered BLM- sensitive or are FWS Birds of Conservation Concern. However, and as <br />conditioned, the contribution of lease tract development in the context of other land uses and <br />processes that are currently prevalent in northwest Colorado and northeast Utah (e.g., oil and gas <br />development, livestock grazing, vehicle -based recreation, proliferation of invasive annual <br />weeds), and relative to the extent of functional habitat that remains available in the more <br />immediate lower White River valley (ferruginous hawk, burrowing owl, gray vireo) and more <br />expansive woodlands of northwest Colorado (titmouse, jay), are immeasurably small and <br />undetectable at any landscape scale and are of no practical consequence to the abundance, <br />distribution, or viability of any population of migratory bird. <br />Environmental Consequences of the No Action Alternative: <br />Direct and Indirect Effects: There would be no use authorized that would have potential <br />to exert direct or indirect impacts on migratory birds or associated habitats. <br />Cumulative Effects: The incremental contribution of lease tract development to adverse <br />habitat modifications or behavioral nesting- season influences at the regional or local scale would <br />DOI- BLM -CO- 110 - 2012 - 0023 -EA 53 <br />