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Vantage to Pomona Heights Chapter 3 230 kV Transmission Line Project FEIS Affected Environment PAGE 3-62 of its time within the 95 percent isopleth. For the purposes of analysis, this will represent the “population range.” Likewise, 80 percent of the Sage-Grouse usage can be expected to occur within the 80 percent isopleth, i.e. the “core population range.” The estimated population range and core population range facilitate comparison of relative densities of Sage-Grouse use and aid in predicting the level of impact the proposed Project would have on the overall YTC Sage-Grouse population. Available location data include three telemetry studies from Sage-Grouse captured on JBLM YTC. These studies range from 25 years old to present, with specific years of study including 1989-1993, 1999-2001, and 2012-2014. Other available location data include a telemetry study from Sage-Grouse translocated to JBLM YTC from Oregon and incidental observations collected from 1969 through 2012. All of these data are presented in Figure 3.3-2 to show documented Sage-Grouse use in and around the eight-mile-wide Sage-Grouse analysis area. Data from translocated birds were not analyzed as it is unlikely that newly transplanted birds would provide an accurate picture of use by the local population. Incidental observations were not analyzed because the lack of standardized protocol and opportunistic nature of those observations would lead to biased results that would have as much or more to do with density of use by human observers as density of use by Sage-Grouse. Sage-Grouse experts from BLM, JBLM YTC, and USFWS determined that data from the three telemetry studies of locally captured Sage-Grouse would be retained and used for the kernel analysis. In each study, Sage-Grouse were captured at a broad array of lekking areas throughout the population area and are assumed to provide a spatially representative sample of the overall population (Cadwell et al. 1998; Livingston and Nyland 2002; Stell Environmental Enterprises [SEE] 2013). A comparison of utilization distribution generated separately for each of the three study periods (1989- 1993, 1999-2001, and 2012-2014) revealed a substantial difference among study periods. Telemetry data from the 2012-2014 study were selected for the final analysis because the impact of the proposed Project on Sage-Grouse can be most reliably assessed using the current distribution of Sage-Grouse (see Figure 3.3-4). A time series, displaying utilization distribution from each study period, is displayed in Figure 3.3-5. Based on the kernel density model, the current population range (95 percent isopleth) does not overlap any route segments within the proposed NNR Alternative ROW, nor with Route Segments 3a, 3b, or 3c (Figure 3.3-4). This does not indicate that absolutely no Sage-Grouse use ever occurs in these route segments, but that use would be expected to be very rare relative to the area within the estimated population range; approximately five percent of all Sage-Grouse use is expected to occur outside of the population range. Estimates beyond the 95 percent range are not typically attempted and would not be reliable (Fuller et al. 2005). During ground transect surveys conducted along the proposed NNR Alternative in May and July of 2013, no Sage-Grouse were observed; however, Sage-Grouse scat was observed in six locations adjacent to the following route segments: NNR-6, one location on NNR-5 and one location on NNR-4. These results indicate that some Sage-Grouse use of the NNR Alternative ROW does occur, but that use is rare. The estimated 95 percent isopleth Sage-Grouse population range does barely overlap the eight-mile wide Sage-Grouse analysis area of the NNR Alternative and MR Subroute (18 percent of NNR-2, 16 percent of NNR-3, and less than10 percent for all other NNR Alternative Route Segments), but the core population range (80 percent isopleth) does not. At the southeastern part of the Project study area, the 95 percent population range overlaps ten percent of the Route Segment 3b analysis area and two percent of the Route Segment 3c analysis area. In the northeastern part of the Project study area, the 95 percent population range is not within four miles of Route Segments NNR-7, NNR-8, or 3a.