Abstract
The Shiloh II Wind Power Project Area is situated on roughly 7,800 acres of agricultural land in the Montezuma Hills, near Rio Vista in Solano County, California. The project consists of 75 wind turbines rated at 2.0 MW each for a total capacity of up to 150 MW. Thirty-three of the turbines are mounted on 68.5 meter towers and forty-two are on 78 meter towers. The rotor diameter is 94 m (308 feet). The height of the rotor when in the 12 o’clock position for turbines with the 68.5 m towers is 115 m (377 feet), and for the 78 m towers is 125 m (410 feet). These turbines are arrayed on similar landscape and habitat as that in which approximately 510 turbines of an older, smaller technology are deployed along with more than 200 turbines of the newer, larger technology.
The Collinsville-Montezuma Hills Wind Resource Area (CMHWRA) consists of approximately 40,300 acres and existing wind plants including Shiloh II, occupy approximately 25,100 acres. The landscape consists of rolling hills with elevations ranging from just above sea level adjacent to the Sacramento River to about 250 - 300 feet (61-91 m). Turbines are placed on the highest ground and do not run through low-lying valleys. Moving from south to north the terrain becomes more uniform with less elevation differential between the ridges and the valleys. On the west is the Suisun Marsh.
The land is private and largely agricultural, mostly rotating crop varieties and grazed pastures. There are isolated wetlands (mostly cattail marsh). Treed areas within the project are limited to the areas close to homes and in a few valleys, consisting of non-native eucalyptus, olive, and some native oaks and junipers.
This report details the first year of an ongoing three year post-construction study of the Shiloh II wind power project, the fourth study of the newer turbine technology in the CMHWRA. The previous three-year study was conducted at the Shiloh I project, from April 10, 2006 to April 11, 2009. Prior to that study, there was a two year study conducted at the adjacent High Winds project from August, 2003 through July, 2005. During the first twelve months (April 27, 2009 to April 24, 2010) of this three-year study, carcass surveys were conducted once per week at 25 of the 75 wind turbines, for a total of 52 rounds. In addition to reporting the results of the study, we provide details regarding the fulfillment of the Solano County Use Permit U-05-25, specifically BIO 9a and Condition 34.
A total of 44 wind turbine related avian incidents were recorded over the first year by searchers during standardized surveys, representing 19 species and 2 unidentified birds (1 of these was a blackbird, and 1 was an unidentifiable grebe). Of the 19 avian species, 2 were raptor species including American Kestrel (n = 1) and Red-tailed Hawk (3), comprising a total of 4 raptor incidents during the first year. The largest numbers of carcasses found were songbirds, comprising 27 incidents (61.4%), and representing 11 species and an unidentifiable blackbird. There were three waterfowl incidents, all Mallards, and 6 waterbird incidents (2 Black Rails, 1 Sora, 1 Dunlin, 1 Long-billed Curlew, and 1 unidentified grebe).
Two California Black Rails, a State Threatened species, were found in year one. No Federally threatened or endangered species were found. There was also one incident of a California Species of Special Concern, the Yellow Warbler.
Thirty-two (32) bat carcasses of three species were found: Hoary Bat (8); Mexican Free-tailed Bat (21); and Western Red Bat (3).