altamont 2013 draft final...

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Levin Nason – Field Supervisor

Search Crew

Jess Schwartz

Brian Karas

Julie Yee

Michael Morrison

Jim Estep

SRC

Renee Culver

AcknowledgementsM108

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Sampled 45% of turbines in APWRA from 2005 - 2009

Sampled 26% of turbines in APWRA from 2010 - 2013

Long search intervals (averaged 30-51 days depending on year)

Detection probability estimates from 3 studies spanning 8 years

Stratification and new analytical framework in 2010

Avian use surveys

Characteristics of the Study

Turbine Types and Distribution

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Hazardous Turbine Identification and Removal

• 284 Turbines (30 MW) Removed from 2005-2009

Seasonal Shutdown of Turbines• 2006-2007 – APWRA shut down for 2

months• 2008 – APWRA shut down for 3

months• 2009 – 2013 – APWRA shut down for

3.5 months

Repowering• Diablo Winds – 20 MW came online in

2005• Buena Vista – 38 MW came online in

2007• Vasco Winds – 78 MW came online in

2012

Management Actions

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Average Installed Capacity In the Altamont Pass Wind Resource Area

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Conducted all years of the study

12,305 surveys completed over all years

Most prevalent species in 2013• Gulls• Common raven• Red-tailed hawk• Blackbird species

14 species of raptor

Red-tailed hawk 5 times more prevalent than next most abundant focal species

Avian Use

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American Kestrel Seasonal and Annual Variation in Use

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Golden Eagle Seasonal and Annual Variation in Use

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Red-tailed Hawk Seasonal and Annual Variation in Use

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72 species documented as fatalities• 15 raptor species

Five most common native fatalities include:

• Western meadowlark• Red-tailed hawk• Burrowing owl• Gulls • American kestrel

23 valid bat fatalities in 9 years

Two new species in 2013• Acorn woodpecker• Eared grebe.

Fatality Incidents

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Native species with highest fatality rates:

• Western meadowlark• Burrowing owl• American kestrel• Red-tailed hawk• Gulls • Mourning dove• Barn owl

Fatality Rates

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Annual Variation in Fatality Rates at Old-Generation Turbines

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APWRA – Wide Fatalities

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Annual Variation in Estimates of APWRA-Wide Total Fatalities

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Settlement Agreement Baseline• Unreliable (same data set produced

estimates differing by up to 43%)• Authors claimed it was an

underestimate• Detection probability not measured• Endpoint not specified

New “Baseline”• 3-year rolling average (geometric

mean)• Cannot remove potential influence of

shutdowns and turbine removals that occurred from 2005 - 2007

• Annual detection probability not measured

• Endpoint not specified

Measuring the Reduction in APWRA-Wide Fatalities

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Three-year Rolling Averages of Estimated APWRA-Wide Total Fatalities

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Original baseline point estimate(s) to the point estimate(s) from the last year of the monitoring program (i.e., 2013 monitoring year).

Original baseline point estimate(s) to the 3-year rolling average of the point estimate(s) of the last 3 years of the monitoring program (i.e., 2011–2013 monitoring years).

Alternative baseline point estimate(s) to the point estimate(s) from the last year of the monitoring program (i.e., 2013 monitoring year).

Alternative baseline point estimate(s) to the 3-year rolling average of the point estimate(s) of the last 3 years of the monitoring program (i.e., 2011–2013 monitoring years).

Various Measures of the Reduction in APWRA-Wide Fatalities

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Species

SettlementAgreement

3‐YearRollingAverageBaseline

3‐YearRollingAverage2010–2013

2013EstimatedTotalFatalities

PercentReductionfrom:

3‐YearRollingAverageto3‐YearRollingAverage

3‐YearRollingAverageto2013MonitoringyearEstimate

SettlementAgreementto3‐YearRollingAverage

SettlementAgreementto2013MonitoringyearEstimate

Americankestrel

333 296 225 144 ‐24% ‐51% ‐32% ‐57%

Burrowingowl

380 363 182 109 ‐50% ‐70% ‐52% ‐71%

Goldeneagle

117 57 38 35 ‐34% ‐39% ‐68% ‐70%

Red‐tailedhawk

300 238 146 118 ‐39% ‐50% ‐51% ‐61%

Totalfocalspecies

1,130 954 591 406 ‐38% ‐57% ‐48% ‐64%

Table 3-16: Various Measures of the Reductionin Total Annual Fatalities of the Four Focal Species

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Hazardous Turbine Removal

Repowering

Seasonal Shutdown

Management Actions to Reduce Fatalities

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Annual Variation in Fatality Rates at Santa Clara Turbines and Non-Santa Clara Old-Generation Turbines

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Three-year Rolling Averages of Estimated APWRA-Wide Total Fatalities

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SpeciesSettlementAgreement








SettlementAgreement2013MonitoringyearEstima

Americankestrel

333 296 225 144 ‐24% ‐51% ‐32% ‐57%

Burrowingowl

380 363 182 109 ‐50% ‐70% ‐52% ‐71%

Goldeneagle

117 57 38 35 ‐34% ‐39% ‐68% ‐70%

Red‐tailedhawk

300 238 146 118 ‐39% ‐50% ‐51% ‐61%

Totalfocalspecies

1,130 954 591 406 ‐38% ‐57% ‐48% ‐64%

Table 3-16: Various Measures of the Reductionin Total Annual Fatalities of the Four Focal Species

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Annual Variation in Fatality Rates at Diablo Winds Turbines and Old-Generation Turbines

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Species

AverageAnnualAdjustedFatalityRate(95%CI)

APWRA‐WideOlder‐GenerationTurbinesa

DiabloWindsTurbinesb

BuenaVistaTurbinesc

VascoWindsTurbinesd

Americankestrel 0.56(0.37–0.74) 0.07(0.05–0.09) 0.15(0.06–0.24) 0.21(0.00–0.45)Burrowingowl 0.67(0.44–0.90) 0.58(0.39–0.77) 0.00(0.00–0.00) 0.05(0.01‐0.13)Goldeneagle 0.09(0.07–0.10) 0.02(0.02–0.02) 0.04(0.01–0.07) 0.04(0.00‐0.10)Red‐tailedhawk 0.40(0.33–0.47) 0.28(0.24–0.32) 0.10(0.05–0.15) 0.44(0.00‐0.92)Totalfocalspecies 1.71(1.21–2.21) 0.94(0.69–1.20) 0.29(0.18–0.40) 0.73(0.00–1.61)a Fatalityrateswerecalculated across all years of the study (2005–2013monitoring years).b FatalityrateswerecalculatedusingDiabloWindsturbinesonlyforthe2005–2009monitoringyears.c Fatalityratesbasedon3yearsofmonitoringconductedfromFebruary2008throughJanuary2011.d Fatalityratesbasedon2yearsofmonitoringconductedfromMay2012toMay2014.

Table 3-14. Average Annual Adjusted Focal Species Fatality Rates (Fatalities per MW and 95% CI) for all Monitored Older-Generation Turbines and Three Repowered Operating Groups (Diablo Winds, Buena Vista and

Vasco Winds

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2006-2007 – APWRA shut down for 2 months

2008 – APWRA shut down for 3 months

2009 – 2013 – APWRA shut down for 3.5 months

Seasonal Shutdown

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0

0.1

0.2

0.3

0.4

0.5

Mean De

tections

Per

Minute Per k

m3

American Kestrel Use

Outside Shutdown Period Inside Shutdown Period

American Kestrel Use During and Outside the Seasonal Shutdown

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0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

Mean De

tections

Per

Minute Per k

m3

Golden Eagle Use


Golden Eagle Use During and Outside the Seasonal Shutdown

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00.20.40.60.81

1.21.41.61.8

Mean De

tections

Per

Minute Per k

m3

Red‐tailed Hawk Use


Red-tailed Hawk Use During and Outside the Seasonal Shutdown

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0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

ferruginous hawk northern harrier prairie falcon rough‐legged hawk

Mean De

tections Per M

inute Per k

m3

Use by Other Raptors in the APWRA


Raptor Use During and Outside the Seasonal Shutdown

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Species

DuringShutdownPeriod

OutsideShutdownPeriod

TotalAnnualFatalities

ProportionofFatalitiesDuringShutdown

2PValue

Americankestrel(Observed) 22 78 100 22% Americankestrel(Expected) 29 71 100 29% 0.12

BurrowingOwl(Observed) 48 50 98 49% BurrowingOwl(Expected) 28 70 98 29% 0.00

Goldeneagle(Observed) 3 49 52 6% Goldeneagle(Expected) 15 37 52 29% 0.00

Red‐tailedhawk(Observed) 19 147 166 11% Red‐tailedhawk(Expected) 48 118 166 29% 0.00

1. Expected values based on the length of the shutdown period relative to the rest of the year and assumptions that turbines continue spinning and collision risk rmains constant across the year

Table 3-9. Observed and Expected1 Values of the Total Fatalities Estimated to Have Occurred During and Outside the Seasonal Shutdown Period for the

2009–2013 Monitoring Years Based on the Proportion of the Monitoring Year Occurring During the Shutdown Period

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Table 3‐X. Detection Rates (Detections Per Turbine Search) for the Four Focal Species Inside and Outside the Shutdown Period in Monitoring Years 2009‐2013.

Species

FatalitiesPerTurbineSearchInsideShutdownPeriod

FatalitiesPerTurbineSearchOutsideShutdownPeriod OddsRatio

Fisher’sExactTest(2‐sided)Probability

Americankestrel 22/26256 78/61798 0.6636 0.1005BurrowingOwl 48/26256 50/61798 2.2618 0.0000Goldeneagle 3/26256 49/61798 0.1140 0.0000Red‐tailedhawk 19/26256 147/61798 0.3037 0.0000Total 92/26256 324/61798 0.6671 0.0005

Table 3‐X. Detection Rates (Detections Per String Search) for the Four Focal Species Inside and Outside the Shutdown Period in Monitoring Years 2009‐2013.

Species

FatalitiesPerStringSearchInsideShutdownPeriod

FatalitiesPerTurbineSearchOutsideShutdownPeriod OddsRatio

Fisher’sExactTest(2‐sided)Probability

Americankestrel 22/3060 78/7263 0.6671 0.0993BurrowingOwl 48/3060 50/7263 2.2988 0.0000Goldeneagle 3/3060 49/7263 0.1449 0.0000Red‐tailedhawk 19/3060 147/7263 0.3025 0.0000Total 92/3060 324/7263 0.6639 0.0005

Detection Rates for the Four Focal Species Inside and Outside the Shutdown Period in Monitoring Years 2009-2013

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Speciesa


OutsideShutdownPeriod

TotalAnnualFatalities

ProportionofFatalitiesDuringShutdown

2PValue

Americankestrel(Observed) 22 78 100 22% Americankestrel(Expected) 38 62 100 38% 0.014Goldeneagle(Observed) 3 49 52 6% Goldeneagle(Expected) 17 35 52 33% 0.000Red‐tailedhawk(Observed) 19 147 166 11% Red‐tailedhawk(Expected) 63 103 166 38% 0.000a Usesurveyswerenot designed to assess use for burrowing owls andaretherefore not reported.

Table 3-10. Observed and Expected Values of the Total Fatalities Estimated to Have Occurred During and Outside the Seasonal Shutdown Period for the

2009–2013 Monitoring Years Based on the Total Number of Daylight Hours in Each Period and Estimates of Bird Use

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Species


OutsideShutdownPeriodFeatherSpots

TotalFatalities

%FeatherSpot

FeatherSpots

TotalFatalities

%FeatherSpot

Americankestrel 17 22 77% 32 78 41%Burrowingowl 44 48 92% 17 50 34%Goldeneagle 0 3 0% 2 49 4%Red‐tailedhawk 5 19 26% 6 147 4%

Table 3-11. Proportion of Fatality Incidents of the Four Focal Species Occurring during and outside the Seasonal Shutdown Comprised of

Feather Spots at Older-Generation Turbines in the APWRA, Monitoring years 2009–2013

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Species 2005 2006 2007 2008 2009 2010 2011 2012 2013

Americankestrel 0% 9% 27% 14% 24% 25% 17% 15% 29%

Burrowingowl 4% 23% 34% 30% 32% 46% 67% 81% 27%

Goldeneagle 0% 0% 11% 8% 9% 9% 0% 0% 9%

Red‐tailedhawk 17% 16% 9% 8% 14% 4% 21% 11% 11%

The proportion of annual fatalities occurring during the seasonal shutdown increases over time for burrowing owls (r2 = 0.462, p = 0.042) and perhaps for American kestrel (r2 = 0.363, p = 0.088).

Table 3-12. Fatality Incidents of the Four Focal Species Occurring During and Outside the Seasonal Shutdown at Older-Generation Turbines,

Monitoring years 2005–2013

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Located ridges without turbines (controls, n = 34 ridges)

Most ridges previously had turbines on them (all but 3) and most still had a power box (rectangular box standing about 3 ft. high)

Matched pairs design with area searched kept equal between treatment and control.

Selected matching ridges with turbine strings (treatments) based on ridge location, elevation, direction, and habitat, usually a ridge immediately or almost immediately adjacent to the control ridge.

In some cases, we had to select more than one turbine string or a partial turbine string to keep treatment and control search areas equal.

At least two rounds of clearing searches at sites not previously searched

Background Mortality Study

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Valid Fatalities Detected At Ridges with Turbines (Treatment) and Without Turbines (Control)Species Treatment Control SizeBarn owl 1 0 LargeRed-tailed hawk 0 2 LargeUnknown large bird 2 2 LargeTotal Large Birds 3 4American kestrel 1 1 SmallAmerican robin 2 2 SmallBlackbird 1 0 SmallBurrowing owl 3 0 SmallEuropean starling 6 3 SmallHorned lark 4 3 SmallMourning dove 2 0 SmallSavannah sparrow 3 0 SmallUnknown small bird 5 2 SmallVaried thrush 0 1 SmallWestern meadowlark 4 2 SmallTotal Small Birds 31 14Unknown dove 1 0 UnknownUnknown medium bird 3 2 UnknownTotal Birds 38 20

Background Mortality Study - Results

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Conducted a total of 338 regular primary searches at treatment and control strings

Average Search Interval = 10.6 days

For small birds, n (treatment) = 31, n (control) = 14

Fisher’s exact test (two-tailed), p = 0.0129

Conclusions• Significantly more small bird fatalities are detected on ridges with non-operating

turbines than on ridges without turbines.• Non-turbine-related fatalities clearly occur during the seasonal shutdown period

for small birds subject to predation, and occasionally for larger birds.

Background Mortality Study - Results

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Three-year Rolling Averages of Estimated APWRA-Wide Total Fatalities with Shutdown Period Fatalities Excluded

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SpeciesSettlementAgreement








SettlementAgreementto2013MonitoringyearEstimate

Americankestrel 333 227 186 119 ‐18% ‐47% ‐44% ‐64%

Burrowingowl 380 236 74 79 ‐69% ‐67% ‐80% ‐79%

Goldeneagle 117 57 38 35 ‐34% ‐39% ‐68% ‐70%

Red‐tailedhawk 300 238 146 118 ‐39% ‐50% ‐51% ‐61%

Totalfocalspecies 1,130 758 444 351 ‐41% ‐54% ‐61% ‐69%

Table 3-18. Various Measures of the Reduction in Total Annual Fatalities of the Four Focal Species if Fatalities for Small Birds Potentially Subject to Predation with an Estimated Death Date During the Seasonal Shutdown

Period are Excluded from Analysis

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Estimates of APWRA-Wide Fatality Estimates for the Four Focal SepciesWith and Without Shutdown Fatalities Removed

SpeciesMonitoringYear

Average2005 2006 2007 2008 2009 2010 2011 2012 2013Americankestrel 236 369 298 201 196 185 264 301 144 244Burrowingowl 225 783 272 130 231 158 296 187 109 266Goldeneagle 70 68 38 28 31 35 38 40 35 43Red‐tailedhawk 304 247 180 94 81 168 176 150 118 169Totalfocalspecies 836 1,468 788 453 540 547 774 677 406 721

Estimated Annual Total APWRA-Wide Fatalities

SpeciesMonitoringYear

Average2005 2006 2007 2008 2009 2010 2011 2012 2013Americankestrel 179 253 177 135 139 125 186 218 93 167Burrowingowl 182 388 131 57 131 64 83 41 65 127Goldeneagle 66 66 36 26 29 33 34 36 31 40Red‐tailedhawk 286 238 173 89 76 159 158 128 97 156Totalfocalspecies 712 945 517 306 375 381 461 423 286 490

Estimated Annual Total APWRA-Wide Fatalities with Shutdown Fatalities Excluded

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The preponderance of the evidence suggests that there has been a significant reduction in turbine-related focal species fatalities in the APWRA, and that the 50% reduction goal was achieved through removal of hazardous and non-hazardous turbines, an increase in the duration and intensity of the seasonal shutdown, and the repowering of portions of the APWRA.

The limited evidence available suggests that identification and removal of hazardous turbines has reduced American kestrel, red-tailed hawk, and perhaps burrowing owl fatalities, at least in the BLOB containing the Santa Clara operating group.

The preponderance of the evidence suggests that predation is a significant mortality factor in the APWRA (for those species typically subject to predation) during the winter, and that this has had substantial confounding effects related to measuring annual variation in fatality rates and estimates of total APWRA-wide fatalities, measuring reductions in fatalities over time, and evaluating the effects of management actions, including repowering, on turbine-related fatalities, particularly for burrowing owls.

The available evidence suggests that repowering the APWRA with larger modern turbines would result in a significant reduction in the number of raptors killed per MW of power produced, although the size of the reduction may be overestimated for those species subject to predation.

Conclusions

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Largest and longest avian fatality monitoring project in history

After failure to show reduction in fatalities, changed the monitoring program to allow investigation of related issues

Assessed and determined priorities and commisioned burrowing owl distribution and abundance study

Advanced the science of detection probabilityestimation• Jesse Schwartz, followed by Brian Karas and Julie Yee

First to recognize and demonstrate interdependence of searcher efficiency and carcass removal

Commisioned Background Mortality Study which demonstrated substantial background mortality occurs during the winter in the APWRA

Accomplishments

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Until the next time

The End

November 2015

Prepared for:

Alameda County Community Development Agency

altamont 2013 draft final...

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