Altamont Pass Wind Resource Area Bird Fatality Study

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Bird Years 2005–2010

Altamont Pass Wind Resource Area Bird Fatality Study

December 2012

Prepared for:

Alameda County Community Development Agency

M94

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Distribution and Abundance of Turbine Types

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Distribution of Turbines Monitored, 2005–2009 BYs

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Distribution of Turbines Monitored, 2010 BY

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Distribution of OPs Surveyed,2005–2010 BYs

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Changes in Installed Capacity, 2005–2010

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Search Effort and Average Search Interval (Days ±1 SD), Bird Years 2005–2010

Bird Year Strings Searched Turbines Searched Average Search Interval (Days ± 1 SD)

2005 302 2,118 49.6 (3.49)

2006 340 3,211 35.0 (1.23)

2007 340 3,571 34.5 (0.58)

2008 340 4,090 29.4 (0.50)

2009 334 3,543 33.5 (0.51)

2010 262 1,817 34.1 (1.61)

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Shutdown Type Years November December January FebruaryCrossover 2005 Crossover Crossover Crossover Crossover

Crossover 2006 Crossover Crossover Crossover Crossover

Phased universal 2-month shutdown

2007 Phased Shutdown Phased Phased

Phased universal 3-month shutdown

2008 Phased Shutdown Shutdown Phased

Universal 3-month shutdown

2009 Shutdown Shutdown Shutdown Operating

Universal 3-month shutdown

2010 Shutdown Shutdown Shutdown Operating

Notes:Crossover = Turbines in half of the APWRA were shut down while the other half continued normal operations.Phased = Individual turbine strings were shut down immediately following a search of that string by the MT.Universal = All turbines APWRA-wide were completely shut down simultaneously.

Timing, Duration, and Other Characteristics of the Winter Shutdown of Turbines, Bird Years 2005–2010

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Turbine Removals (Megawatts) in the APWRA, Bird Years 2005–2010Number of Turbines (MW) Removed per Bird Year

2005 2006 2007 2008 2009 2010

Attrition 131 (12) 242 (39) 76 (9) 80 (8) 148 (15) 17 (2)

Tier and Hazardous Turbinesa 0 (0) 23 (2) 100 (10) 106 (11) 55 (6) 18 (2)

Total 131 (12) 265 (41) 176 (19) 186 (19) 203 (21) 35 (4)a Both Smallwood and Spiegel (2005a, 2005b, and 2005c) and the APWRA Scientific Review Committee (2007) identified

turbines in the APWRA to be removed, relocated, or permanently shut down to reduce avian fatalities. These two ranking systems are not mutually exclusive; some turbines identified for removal by Smallwood and Spiegel were also identified by the Scientific Review Committee.

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Base Layer of Operating Group Boundaries (BLOBs)

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Avian Fatalities in the APWRA Excluded from Analysis, BYs 2005–2010

Reason for Exclusion

Number of Fatalities Excluded by Bird Year

Total

Total Fatalities before Exclusion

Total Fatalities after Exclusion2005 2006 2007 2008 2009 2010

Not turbine-related 14 23 29 38 56 15 175 6,133 5,958

WRRS recordsa 46 56 59 61 51 74 347 5,958 5,611

Found beyond 125 meters 1 6 15 4 2 1 29 5,611 5,582Older than 90 days or of undeterminable age

37 75 326 140 145 101 824 5,582 4,758

Unidentifiable or injured birds 0 3 9 11 3 6 32 4,758 4,726

Backdated to 2004 88 n/a n/a n/a n/a n/a 88 4,726 4,638

Total 186 163 438 254 257 197 1,495 6,133 4,638n/a = not applicable.

WRRS = Wildlife Reporting Response System.a Excludes golden eagle records from monitored turbines; these records were retained for analysis.

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SEASONAL CHANGES IN FATALITIES AND BIRD USE AND UNADJUSTED FATALITY RATES

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Average Number of Unadjusted Fatality Detections (±95% CI) per Month

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Average Unadjusted Fatalities per Month (±95% CI) and Bird Use (±95% CI)—Focal Species

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Unadjusted Fatality Rates (Fatalities per MW ±95% CI)—Focal Species, BYs 2005–2010

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DETECTION PROBABILITY ESTIMATES

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Searcher Detection Probabilities for Various Bird Groups in the APWRABird Group Searcher Detection Probability

Medium and large raptors 100%

Medium and large non-raptors 80%

Small raptors 75%

Small non-raptors 51%

Source: Smallwood 2007

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Predicted Proportion of Bird Carcasses Remaining

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QAQC Study

233 Carcasses Used in 233 Trials

29 Species

109 Raptors

Used Wingspan instead of Adjustment Groups

Covered All Seasons

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Number of QAQC Carcass Trials in each of Four Adjustment Groups

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Seasonal Distribution of QAQC Carcass Trials in each of Four Adjustment Groups

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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

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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

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QAQC and Modified Smallwood (2007) Detection Probabilities (±95% CI)—Focal Species

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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.

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ADJUSTED FATALITY RATES

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Adjusted Fatality Rates (Fatalities per MW ±95% CI) Using QAQC and Modified Smallwood Detection Probabilities—Focal Species, BYs 2005–2010

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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

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Annual Adjusted Focal Species Fatality Rates (Fatalities per Megawatt and 95% CI) Based on QAQC Detection Probabilities, BYs 2005–2010

SpeciesBird Year and Rate (95% CI)

2005 2006 2007 2008 2009 2010American kestrel 0.34

(0.30–0.38)0.58 (0.52–0.63)

0.59 (0.54–0.65)

0.40 (0.36–0.43)

0.37 (0.34–0.39)

0.44 (0.36–0.52)

Burrowing owl 0.53(0.47–0.59)

1.63 (1.49–1.77)

0.59 (0.54–0.64)

0.26 (0.23–0.29)

0.47 (0.43–0.51)

0.42 (0.34–0.49)

Golden eagle 0.08 (0.07–0.08)

0.17 (0.16–0.18)

0.08 (0.07–0.08)

0.05 (0.05–0.05)

0.06 (0.05–0.06)

0.07(0.06–0.08)

Red-tailed hawk 0.62(0.59–0.66)

0.78 (0.73–0.82)

0.39 (0.38–0.41)

0.21 (0.20–0.22)

0.18 (0.17–0.19)

0.45(0.41–0.48)

Total focal species 1.58 (1.50–1.66)

3.15 (2.99–3.30)

1.65 (1.58–1.73)

0.92 (0.87–0.96)

1.07 (1.03–1.12)

1.38 (1.26–1.49)

Annual Adjusted Focal Species Fatality Rates (Fatalities per Megawatt and 95% CI) Based on Modified Smallwood (2007) Detection Probabilities, BYs 2005–2010

SpeciesBird Year and Rate (95% CI)

2005 2006 2007 2008 2009 2010American kestrel 0.57

(0.50–0.71)0.90 (0.78–1.01)

0.92 (0.80–1.05)

0.57 (0.51–0.63)

0.56 (0.50–0.62)

0.69 (0.55–0.84)

Burrowing owl 0.90 (0.75–1.05)

2.43 (2.16–2.70)

0.88 (0.79–0.98)

0.36 (0.31–0.41)

0.70 (0.62–0.78)

0.62 (0.49–0.75)

Golden eagle 0.07 (0.07–0.08)

0.16 (0.15–0.17)

0.07 (0.07–0.08)

0.05 (0.05–0.05)

0.05 (0.05–0.06)

0.07 (0.05–0.08)

Red-tailed hawk 0.39 (0.37–0.41)

0.54 (0.51–0.58)

0.28 (0.26–0.29)

0.15 (0.14–0.16)

0.13 (0.12–0.13)

0.32 (0.29–0.34)

Total focal species 1.93 (1.77–2.14)

4.03 (3.73–4.32)

2.16 (2.00–2.32)

1.13 (1.05–1.21)

1.44 (1.35–1.54)

1.70 (1.50–1.89)

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APWRA-WIDE ESTIMATES OF TOTAL FATALITIES

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APWRA-Wide Estimates of Total Annual Fatalities (±95% CI) Based on QAQC and Modified Smallwood (2007) Detection Probabilities―Focal Species, BYs 2005–2010

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Bird Use and Total APWRA-Wide Fatalities (±95% CI) Based on QAQC Detection Probabilities, BYs 2005–2010

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Three-year Rolling Averages of Estimated Annual Total Fatalities (±95% CI) Based on QAQC and Modified Smallwood (2007) Detection Probabilities, BYs 2005–2010

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Annual Estimated Total APWRA-Wide Focal Species Fatalities (95% CI) Based on QAQC Detection Probabilities, BYs 2005–2010

SpeciesBird Year and Fatalities (95% CI)

2005 2006 2007 2008 2009 2010American kestrel 207

(182–231)344 (308–380)

347 (316–379)

213 (196–230)

203 (186–220)

205 (173–273)

Burrowing owl 237 (214–260)

837 (762–912)

285 (260–310)

138 (122–154)

216 (196–237)

190 (162–218)

Golden eagle 64 (60–67)

99 (94–105)

43 (41–44)

29 (28–29)

43 (41–45)

38 (33–43)

Red-tailed hawk 339 (322–357)

429 (405–452)

202 (195–210)

103 (99–108)

94 (89–100)

206 (191–220)

Total focal species 846 (778–914)

1,709 (1,568–1,849)

877 (811–943)

483 (445–521)

556 (511–601)

638 (559–718)

Annual Estimated Total APWRA-Wide Focal Species Fatalities (95% CI) Based on Modified Smallwood (2007) Detection Probabilities, BYs 2005–2010

SpeciesBird Year and Fatalities (95% CI)

2005 2006 2007 2008 2009 2010American kestrel 335

(282–388)461 (400–522)

465 (410–519)

263 (237–288)

270 (241–298)

271 (223–320)

Burrowing owl 369 (321–416)

1,131 (1,013–1,248)

385 (345–425)

171 (150–193)

289 (257–321)

254 (213–294)

Golden eagle 57 (53–61)

88 (81–94)

39 (36–41)

26 (24–29)

39 (36–43)

34 (29–39)

Red-tailed hawk 207 (198–216)

275 (259–291)

132 (126–138)

72 (67–76)

64 (60–69)

133 (123–144)

Total focal species 968 (896–1,039)

1,954 (1,820–2,088)

1020 (952–1,088)

532 (499–566)

662 (619–706)

693 (628–757)

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Various Measures of the Reduction in Total Annual Fatalities of the Four Focal Species in the APWRA over Time Based on QAQC Detection Probabilities

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SEASONAL SHUTDOWN

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Winter Fatality Detections (%) for the Four Focal Species at on-Diablo Winds Operating Group Turbines in the APWRA, Bird Years 2005-2010.

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Percentage of Annual Fatalities in Winter at Non–Diablo Winds Turbines—Focal Species, BYs 2005–2010

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Percentage of BUOW and AMKE Fatalities Composed of Feather Spots and Documented in Winter and Non-Winter Periods, BYs 2005–2010

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REPOWERING

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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.

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EFFECTS OF BLEED THROUGH ON ESTIMATES OF TOTAL FATALITIES

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PERCENT BIAS AS A FUNCTION OF SEARCH INTERVAL LENGTH

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Annual Estimated Total APWRA-Wide Focal Species Fatalities Based on QAQC Detection Probabilities, BYs 2005–2010

SpeciesBird Year and Fatalities

2005 2006 2007 2008 2009 2010

American kestrel 207 344 347 213 203 205

Burrowing owl 237 837 285 138 216 190

Golden eagle 64 99 43 29 43 38

Red-tailed hawk 339 429 202 103 94 206

Total focal species 847 1,709 877 483 556 639

Annual Estimated Total APWRA-Wide Focal Species Fatalities Based on QAQC Detection Probabilities, Re-Adjusted to Account for Bleed-Through, BYs 2005–2010

SpeciesBird Year and Fatalities

2005 2006 2007 2008 2009 2010

American kestrel 189 297 299 176 173 176

Burrowing owl 218 720 245 114 184 163

Golden eagle 60 88 38 25 38 34

Red-tailed hawk 325 406 191 97 89 195

Total focal species 792 1,512 773 412 485 567

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2005 2006 2007 2008 2009 20100

100

200

300

400

American Kestrel

StandardAdjusted

Bird YearEstim

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2005 2006 2007 2008 2009 20100

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600

800

1000

Burrowing Owl

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Bird YearEstim

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Red-tailed Hawk

StandardAdjusted

Bird YearEstim

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20406080

100120

Golden Eagle

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SLIDE TITLE

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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.

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Q&A

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