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Vantage to Pomona Heights Chapter 4 230 kV Transmission Line Project FEIS Environmental Consequences PAGE 4-65 would be avian-safe with no potential for electrocution of raptors or other bird species. The proposed Project would result in no identifiable impacts with regard to avian electrocution. Predation Mammalian predators and scavengers may use roads and transmission line ROWs as travel corridors which may facilitate predation on Sage-Grouse (Bennett 1991; Forman and Alexander 1998). Because the Project ROW would occur within sagebrush-steppe and grassland habitats that are already open, the effects of mammalian predation on Sage-Grouse are likely to be less pronounced compared with corridor effects in forested landscapes. In the relatively treeless environment of the Project study area, avian predators are more likely to benefit from a transmission line structures than mammalian predators. Armentrout and Hall (2005) reported that Sage-Grouse nests and adults associated with leks near transmission lines were lost at a higher rate to avian rather than mammalian predators. They reported that predation attributed to mammals actually occurred at a lower rate near transmission lines. Transmission line structures provide substrates for perching, roosting, and nesting for some avian species (i.e., raptors and corvids) (APLIC 2006; Knight et al. 1995; Steenhof et al. 1993). In open areas where natural substrates are limited, this may increase local abundance of avian predator species and increase predation pressures on prey species such as small mammals and nesting birds (Call and Maser 1985; Connelly et al. 2000; Vander Haegen et al. 2002; Howe et al. 2014). While these effects have mainly been documented for terrestrial prey species, predators of fish may also perch on transmission structures and/or transmission lines. The distance that these effects could extend from the transmission line depends on the hunting range of the predator species. Some raptor species may benefit from the proposed Project by the creation of new perching structures from which to hunt prey. Common raven populations have increased fourfold in the western U.S. during the past 40 years (Sauer et al. 2012). Raven populations often increase following human alteration of landscapes due to increased availability of food (e.g., litter associated with human use, roadkill, refuse, landfills), water (e.g., stock ponds, reservoirs), and nesting substrates (e.g., transmission line structures, communication towers, buildings) (Knight and Kawashima 1993; Kristan et al. 2004; Howe et al. 2014). In eastern Idaho, Howe et al. (2014) reported a 31 percent decrease in the odds of nesting by ravens for every 0.6 mile (1.0 kilometer) increase in distance away from a transmission line ROW, with 48 of 82 nests in the study located on transmission line poles. Long-term monitoring of raven nests at JBLM YTC began in 1994. In 1994, 28 raven nests were located on JBLM YTC; seven (25 percent) of them were located on anthropogenic structures, including one on a transmission line structure (Paulus and Malkin 1995). In 2013, 47 raven nests were located on JBLM YTC, a 68 percent increase relative to 1994. Although an attempt is made to locate all raven nests on JBLM YTC each year, search efforts have not been spatially and temporally consistent (JBLM YTC personal communication 2014a). A correlation between raven abundance and transmission lines has been established elsewhere (Howe et al. 2014); at JBLM YTC the distribution of raven nests does not appear to be spatially correlated with the locations of transmission lines. None of the active raven nests identified in 2013 were located on Pacific Power’s existing Pomona-Wanapum 230 kV transmission line structures that the proposed New Northern Route (NNR) Alternative closely parallels. It is unclear if the apparent nesting patterns of ravens at JBLM YTC are real or just an artifact of spatial variation in search effort. The Terrace Heights Landfill is located approximately 2.0 miles south and west of Route Segments 1b and 1c and is likely to provide an abundant source of food for ravens (Paulus and Malkin 1995). Transmission line structures may be more likely to be used by ravens in areas near this abundant food