Appendix B WEST Avian Study Report
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Appendix B WEST Avian Study Report Klickitat County Energy Overlay Environmental Impact Statement ANALYSIS OF POTENTIAL AVIAN/WIND PLANT INTERACTIONS IN KLICKITAT COUNTY, WASHINGTON Supplement to the KLICKITAT COUNTY PROGRAMMATIC ENVIRONMENTAL IMPACT STATEMENT Prepared for Resource Development Department Klickitat County, Washington 127 West Court Street Goldendale, Washington 98620 Prepared by Gregory D. Johnson Wallace P. Erickson M.Dale Strickland Karyn J. Sernka Western EcoSystems Technology, Inc. 2003 Central Ave. Cheyenne, Wyoming 82001 and Karen Kronner Bob Gritske Northwest Wildlife Consultants 815 NW 4th Street Pendleton, Oregon 97801 May 2003 TABLE OF CONTENTS LIST OF TABLES i LIST OF FIGURES LIST OF APPENDICES ii INTRODUCTION Wind has been used to commercially produce energy in the United States since the early 1980's and is considered an important source of renewable energy. Although generally considered environmentally friendly, wind plants have been associated with the death of birds colliding with turbines and other wind plant structures, especially in California, and wind plants can have negative effects on birds and other wildlife if not sited properly. Early wind energy facilities in the U.S. were often constructed in areas without an understanding of the level of avian use at those locations. Consequently, some of these facilities are located where birds are abundant and the risk of turbine collisions is relatively high. High raptor mortality documented at Altamont, California has resulted in a great deal of scrutiny of other wind plant developments. Wind projects have been delayed and sometimes stopped at new wind sites across the country due in part to avian collision concerns. Although most studies have shown both the direct and indirect effects on birds by most wind plants to be minimal, state wildlife agencies, the U.S. Fish and Wildlife Service, and environmental organizations have all expressed concern over the potential impacts of wind plants on birds. To alleviate these concerns and to address potential regional or site-specific impacts, developers must address the potential for avian collision mortality and other wildlife impacts when selecting sites for wind power development. Klickitat County, Washington is preparing a Programmatic Environmental Impact Statement (PEIS) to assist with future siting of wind power and other power developments in the county. Because one of the major issues associated with siting of wind power developments involves the potential for impacts to birds, one component of the PEIS includes an assessment of avian resources in the county so that potential conflicts with birds can be minimized or avoided when selecting sites for future wind power development. The purpose of this report is to provide data on avian use of potential wind power development areas in Klickitat County. METHODS Avian Point Counts Field Methods We sampled areas with the highest potential for wind power development (Wind Class 3-6) using a modified systematic sampling design. Fifty fixed circular plots were established throughout Wind Class 3-6 areas. Forty-eight of the points were in Klickitat County, and 2 were established in Skamania County just across the Klickitat County line (Figure 1). The plots were located so that regions (i.e., < or > 1.5 miles from Columbia River, west of U.S. 97, between U.S. 97 and Rock Creek, east of Rock Creek) as well as representative habitats (e.g., riparian, shrub-steppe, cropland) within the project area were included in the sample. The surveys were conducted at each plot once every 2 weeks, starting in mid-April and continuing through mid-July. This time period covered late migration and the breeding season for most raptors and other birds in the project area. Most point count stations were established along public roads. Avian use surveys were conducted to estimate the temporal and spatial use of the project area by birds. The data collected consisted of counts of bird use of circular plots around observation points during a specific survey period. All birds detected by sight or sound during each survey were recorded. Estimated distance to each bird observed was recorded to the nearest meter. The radius of the circular plots was up to 2,625 feet (800 m) depending on the limitations of the terrain. Each plot was surveyed for 20 minutes each survey day. An equal effort was used for all plots. The behavior of each bird observed and the habitat in which or over which the bird occurred were recorded. Approximate flight height at first observation was recorded to the nearest meter and the approximate lowest and highest flight heights were also recorded. Any comments or unusual observations were also noted. Locations of raptors, other large birds, and any species of concern seen were recorded on the field maps by observation number. Plot surveys were scheduled to cover all daylight hours. During a set of surveys, each 1 plot was visited once. A pre-established schedule was developed prior to the field surveys to ensure that each station was surveyed approximately the same number of times each period of the day and to efficiently utilize personnel time by minimizing travel time between plots. Data Analysis Avian Abundance Species lists were generated by season including all observations of birds detected regardless of their distance from the observer. Seasons were defined as follows: April 15 to May 31 - Spring migration, and June 1 through July 15 – Summer/Breeding season. The number of birds seen during each point count survey was standardized to a unit area and unit time surveyed. The standardized unit time was 20 minutes and the standardized unit area was 2.01 km2 (800-m radius view shed for each station). For example, if four raptors were seen during the 20 minutes at a point with a viewing area of 2.01 km2, these data would be standardized to 4/2.01 = 1.98 raptors/km2 in a 20-minute survey. For the standardized avian use estimates, only observations of birds detected within 800 m of the observer were used. Estimates of avian use (expressed in terms of number of birds/plot/20-minute survey) were tabulated to compare differences in avian use between 1) avian groups, 2) seasons, 3) habitat, and 4) geographic location within the county. The magnitude of avian use among the survey plots was examined to determine possible locations of relatively high avian use within the study area. Avian Diversity and Richness The total number of unique species was calculated by season. The mean number of species observed per survey (i.e., per station per 20-minute survey) was used as an index to avian richness in the study area. Mean number of species per survey was tabulated to illustrate and compare differences between seasons. Avian Flight Height/Behavior The rotor-swept height of many of the newer generation turbines ranges from approximately 30 to 100 m above ground. We used this range to approximate the percentage of birds flying below, within and above typical rotor swept heights and in comparing differential risk of collision between bird groups. The first flight height recorded was used to estimate percentages of birds flying below, within and above the rotor swept height (RSH) of turbines. Avian Risk Index A relative index to collision risk (R) was calculated for bird species observed in the project area using the following formula: R = A*Pf*Pt Where A = mean relative use for species i averaged across all surveys, Pf = proportion of all observations of species i where activity was recorded as flying (an index to the approximate percentage of time species i spends flying during the daylight period), and Pt = proportion of all flight height observations of species i within the rotor-swept height (RSH). This index does not account for differences in behavior other than flight characteristics (i.e., flight heights and proportion of time spent flying). Habitat and Landscape Effects on Avian Use Data were used to compare relative use between regions of Klickitat County. The study area was divided into the following three strata: west of U.S. 97, between U.S. 97 and Rock Creek, and east of Rock Creek (Figure 1). Each of these strata were further divided into those areas within 1.5 miles of the Columbia River and >1.5 miles from the Columbia River. This resulted in a total of 6 strata. The distance of 1.5 miles from the Columbia River was selected as this distance generally includes all areas from the river to the top of the rim north of the river, whereas areas >1.5 miles are generally north of the top of the rim. Effect of habitat was also analyzed on two different scales. Riparian areas usually contain the most abundant and diverse avian communities in the arid West and may largely influence bird abundance. 2 Therefore, we looked at avian use as a function of whether or not riparian zones were present within the survey plot. We also looked at avian use as a function of the dominant habitat present within the plot. Habitats examined included agricultural cropland, shrub steppe, grasslands (including Conservation Reserve Program [CRP] fields), woodlands (including riparian areas) and developed areas. Impact Predictions Predictions of the number of collisions per turbine were calculated by avian group for each of the six regions investigated in Klickitat County. Final avian use and mortality data are currently available for three new- generation wind plants outside California, including the Foote Creek Rim, Wyoming wind plant (Johnson et al. 2000a, Young et al. 2003), the Buffalo Ridge, Minnesota wind plant (Johnson et al. 2000b), and the Vansycle, Oregon wind plant (Erickson et al. 2001a). To estimate potential raptor mortality within Klickitat County, the average raptor fatality rate and raptor use estimate from the three wind plants discussed above was determined.