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M94. Altamont Pass Wind Resource Area Bird Fatality Study. Bird Years 2005–2010. Prepared for: Alameda County Community Development Agency. December 2012. Distribution and Abundance of Turbine Types. Distribution of Turbines Monitored, 2005–2009 BYs.
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M94 Altamont Pass Wind Resource Area Bird Fatality Study Bird Years 2005–2010 Prepared for: Alameda County Community Development Agency December 2012
Search Effort and Average Search Interval (Days ±1 SD), Bird Years 2005–2010
Timing, Duration, and Other Characteristics of the Winter Shutdown of Turbines, Bird Years 2005–2010
Turbine Removals (Megawatts) in the APWRA, Bird Years 2005–2010
Avian Fatalities in the APWRA Excluded from Analysis, BYs 2005–2010
SEASONAL CHANGES IN FATALITIES AND BIRD USE AND UNADJUSTED FATALITY RATES [Call out text goes here]
Average Number of Unadjusted Fatality Detections (±95% CI) per Month
Average Unadjusted Fatalities per Month (±95% CI) and Bird Use (±95% CI)—Focal Species
Unadjusted Fatality Rates (Fatalities per MW ±95% CI)—Focal Species, BYs 2005–2010
DETECTION PROBABILITY ESTIMATES [Call out text goes here]
Searcher Detection Probabilities for Various Bird Groups in the APWRA
QAQC Study • 233 Carcasses Used in 233 Trials • 29 Species • 109 Raptors • Used Wingspan instead of Adjustment Groups • Covered All Seasons
Number of QAQC Carcass Trials in each of Four Adjustment Groups
Seasonal Distribution of QAQC Carcass Trials in each of Four Adjustment Groups
Changes in Searcher Efficiency (and 95% Credible Interval Bands) as Carcasses Age Based on Blind Searches during the QAQC Study for the Four Focal Species
Changes in Detection Probability (and 95% Credible Interval Bands) Over Time Based on Sequences Conducted during the QAQC Study and Information from the Carcass Removal / Scavenging Study
QAQC and Modified Smallwood (2007) Detection Probabilities (±95% CI)—Focal Species
QAQC Derived Estimates of Detection Probability • They are derived from a large number of experimental trials conducted entirely within the local study area, using the same personnel used to search for fatalities. • They are based primarily on carcasses actually killed in the study area, or on carcasses of species known to occur—or are similar to species known to occur—in the study area. The carcasses are also the freshest reasonably available. • They are derived from a composite model that estimates carcass removal and searcher efficiency probabilities simultaneously to account for both variables’ joint dependence on carcass age. The model also accounts for the use of carcasses that are not “fresh” when estimating the removal rate.
ADJUSTED FATALITY RATES [Call out text goes here]
Adjusted Fatality Rates (Fatalities per MW ±95% CI) Using QAQC and Modified Smallwood Detection Probabilities—Focal Species, BYs 2005–2010
3-Year Rolling Averages of Annual Adjusted Fatality Rates (Fatalities per MW and ±95% CI) Based on QAQC and Modified Smallwood (2007) Detection Probabilities―Focal Species, BYs 2005–2010
Annual Adjusted Focal Species Fatality Rates (Fatalities per Megawatt and 95% CI) Based on QAQC Detection Probabilities, BYs 2005–2010 Annual Adjusted Focal Species Fatality Rates (Fatalities per Megawatt and 95% CI) Based on Modified Smallwood (2007) Detection Probabilities, BYs 2005–2010
APWRA-WIDE ESTIMATES OF TOTAL FATALITIES [Call out text goes here]
APWRA-Wide Estimates of Total Annual Fatalities (±95% CI) Based on QAQC and Modified Smallwood (2007) Detection Probabilities―Focal Species, BYs 2005–2010
Bird Use and Total APWRA-Wide Fatalities (±95% CI) Based on QAQC Detection Probabilities, BYs 2005–2010
Three-year Rolling Averages of Estimated Annual Total Fatalities (±95% CI) Based on QAQC and Modified Smallwood (2007) Detection Probabilities, BYs 2005–2010
Annual Estimated Total APWRA-Wide Focal Species Fatalities (95% CI) Based on QAQC Detection Probabilities, BYs 2005–2010 Annual Estimated Total APWRA-Wide Focal Species Fatalities (95% CI) Based on Modified Smallwood (2007) Detection Probabilities, BYs 2005–2010
Various Measures of the Reduction in Total Annual Fatalities of the Four Focal Species in the APWRA over Time Based on QAQC Detection Probabilities
SEASONAL SHUTDOWN [Call out text goes here]
Winter Fatality Detections (%) for the Four Focal Species at on-Diablo Winds Operating Group Turbines in the APWRA, Bird Years 2005-2010.
Percentage of Annual Fatalities in Winter at Non–Diablo Winds Turbines—Focal Species, BYs 2005–2010
Percentage of BUOW and AMKE Fatalities Composed of Feather Spots and Documented in Winter and Non-Winter Periods,BYs 2005–2010
REPOWERING [Call out text goes here]
Average Annual Adjusted Focal Species Fatality Rates (Fatalities Per Megawatt and 95% CI) in the APWRA for the Repowered Buena Vista and Diablo Winds Turbines and All Other Monitored Turbine Strings.
EFFECTS OF BLEED THROUGH ON ESTIMATES OF TOTAL FATALITIES [Call out text goes here]
Annual Estimated Total APWRA-Wide Focal Species Fatalities Based on QAQC Detection Probabilities, BYs 2005–2010 Annual Estimated Total APWRA-Wide Focal Species Fatalities Based on QAQC Detection Probabilities, Re-Adjusted to Account for Bleed-Through, BYs 2005–2010
Conclusions • There is strong evidence of a reduction in raptor fatalities in the APWRA since 2005, concomitant with the general decline in installed capacity, the removal of hazardous turbines, an increase in the duration and intensity of the seasonal shutdown, and the repowering of portions of the APWRA. Some metrics indicate that the 50% reduction in focal species fatalities has been achieved. • There is substantial evidence to support the hypothesis that the winter shutdown has resulted in a decrease in large raptor fatalities, particularly for red-tailed hawk and golden eagle. There also appears to be a beneficial effect for American kestrel. Burrowing owl fatalities do not appear to be directly related to the winter shutdown, and several lines of evidence indicate that these results are confounded by predation-related fatalities. • There is evidence that repowering the APWRA with larger modern turbines would result in a significant reduction in the number of raptors killed per megawatt of power produced.