Wind Energy and Wildlife Concerns

101

October 2008

Milwaukee, Wisconsin

Dale Strickland

Western EcoSystems Technology, Inc.

Cheyenne, Wyoming

Historic Experience of

Avian-Wind and Bat

Interaction

Where did the concern over avian mortality

start?

• Altamont Pass

• 7000+ turbines (now ~5000) of various designs in 60 sq. mile area

• High raptor use

• High prey base

• High raptor mortality• golden eagles

• red-tailed hawks

• American kestrel

• Burrowing owls

• Other owl species

40 – 400 kw

Average size 100 kW – 18 m rotor

diameter

Approximately 100

turbines/mi2

Altamont Results

~50 – 100 golden eagle fatalities

~500 red-tailed hawk fatalities

100+ American kestrel, barn owl and burrowing owl fatalities

Nesting in/on turbines

1 – 2 raptors / MW/ year

Smallwood and Thelander 2004

Other Results From APWRA

Studies Associations of micro-

siting variables with risk. Steepness, aspect, prey base

Still a rare event (1 raptor every 10 turbines per year).

No sign. pop level effect documented on breeding golden eagles; however, effect on floater group uncertain

OTHER EARLY

DEVELOPED

WRA’S Tehachapi Pass and

San Gorgonio also

large WRA with many

older turbines

Altamont raptor

mortality not realized

at Tehachapi and San

Gorgonio

Altamont

Tehachapi

San Gorgonio

EAGLES

Eagle Observation

Project Area Boundary

Section Boundary

0 ½ 1 2

Mi les

A

Count LocationApproximate Raptor Point

N

T20N

T19N

25 30

20

19 20

30

31 33

8

1

12

13

21

Arlington

4

B

C

D

E

F

A

Rim Edge

1999

Eagles

off rim rim edge on rim0.0

0.2

0.4

0.6

0.8

1.0

Buteos

0.0

0.2

0.4

0.6

0.8

1.0

Falcons

0.0

0.2

0.4

0.6

0.8

1.0

All Raptors

0.0

0.2

0.4

0.6

0.8

1.0Use w/i rsaUse w/i rsa

Use w/i rsaUse w/i rsa

off rim rim edge on rim

off rim rim edge on rimoff rim rim edge on rim

FOOTE CREEK RIM WYOMING

• Newer Technology

• Micro-siting

•Lower turbine density per MW

Nocturnal Migrants

No large events documented at wind projects

2 “small events” documented

14 nocturnal migrants found at two adjacent turbines at Buffalo Ridge after thunderstorm

~30 migrants found near floodlit substation and turbines at Mountaineer

Bats and Wind History

“Members of the Audubon

Society classified the birds

into twenty-eight

species…but the presence

of the four red bats

puzzled them most.”

NY Times: 7 October 1954

Communication Towers

WCTV, Leon Co., FL

25 years of monitoring

(1955-1980)

54 bats of 7 species 87% species of Lasiurus

• Eastern red bats

• Hoary bats

• Seminole bats

• Northern yellow bats

86% on autumn nights

some nights only bats

Photo: Paul Schmidt

Crawford and Baker 1981:J. Mammalogy 62:651-652

Bats and Wind Energy

(The Early Years)

No reports in literature of collision mortality from North America

One record of collisions in Australia 22 bats (Nyctinomus australis; a tree-

roosting, potential migrant) over 5 years at Dunlite wind generators (1.2 m blades--Hall and Richards 1972: Australian Mammalogy 1:46-47)

The collision of bats with giant wind turbines is an emerging phenomenon that is unprecedented and was never anticipated

Altamont Pass WRA, CA

Operational in early 1980’s

Arid rangelands

< 10 bats reported

Hoary bats during autumn

No targeted bat search

Photo: www.wikipedia.com

Buffalo Ridge, MN

Operational in 1994

Ag lands – crops and CRP

Bats found among birds in 1994

First quantitative fatality estimates for bats

≤ ~3 bats/turbine/year (bat/t/y)

Johnson et al. 2003: Am. Midl. Nat. 150:332-342

Johnson et al. 2004: Wild. Soc. Bull. 32:1278-1288

Foot Creek Rim, WY

Completed in 2000

Grasslands and shrublands

Searched Nov 1998 – Jun 2002

Estimate ~1-2 bats/t/yr

Photo: Dave YoungYoung et al. 2003a & 2003b: in litt

Foot Creek Rim, WY

Photo: Dave Young

Targeted study of bat roosts and

activity in the area

Turbine mortality does not reflect

local bat species

Hoary bats roosted in tallest trees

when moving through the area

Gruver 2002: unpublished thesis

Buffalo Mountain, TN

Photo: Invenergy LLC

Operational in 2000

3 turbines (660kW)

Forested ridge

Estimate 20 bats/t/yr

Fiedler 2004: unpublished thesis

Mountaineer, WV

Meyersdale, PA Forested ridges

2004 Bat Wind Energy Collaborative 633 bats of 7 species

• 72% tree bats (red, hoary, silver-haired bats)

• 17% eastern pipistrelles

Estimates of mortality during 6-week study period

• 25 to 38 bats per turbine

• Total estimated kill of 1764 to 2900

Arnett et al. 2005: in litt

(BWEC 2004)

Wildlife Collision Fatalities - Birds

ALL REGIONS

11%

3%

74%

1%1%

2%1%

6%

1%

Doves/Pigeons

Gamebirds

Other Birds

Passerines

Rails/Coots

Raptors/Vultures

Shorebirds

Unidentified Birds

Waterbirds

Waterfowl

Sites: BM, Mo, BR, T of I, Condon, WI, NC, SL, Van, FCR, NWTC, and Ponnequin

Species

Pacific

NW Midwest

Rocky

Mtns. East

Grand

Total Rank

horned lark 90 1 18 109 1

ring-necked pheasant 24 2 26 2

golden-crowned

kinglet 20 3 1 24 3

western meadowlark 14 1 2 17 4

gray partridge 13 1 14 5

unknown passerine 6 1 4 1 12 8

red-tailed hawk 9 2 1 12 7

European starling 7 4 1 12 6

white-crowned

sparrow 10 1 11 9

chukar 10 10 10

Total for 126

Species 263 86 80 60 489

Top 10 species ranked by

number of carcasses1

1 Assumes no background fatalities.

2.0

3.33.0

5.9

1.41.0

2.8 2.92.6

1.0

3.1

1.3

11.7

2.7

1.81.4

2.52.0

2.5

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

WI B1 B2 B3 TI VA NC SL CH K1 K2 HR BM MO DW HW F1 F2 AI

# B

ird

Fa

taliti

es

/ M

WAll Birds

Wind Project

Agriculture Ag / Grass / CRP Forest Grass / Steppe

0

0.04

0 0 0.01 0

0.05

0.09

0 0

0.11

0.14

00.02

0.56

0.42

0.05 0.060.07

0

0.1

0.2

0.3

0.4

0.5

0.6

WI B1 B2 B3 TI VA NC SL CH K1 K2 HR BM MO DW HW F1 F2 AI

# R

ap

tor

Fa

taliti

es

/ M

WRaptors

Wind Project

Agriculture Ag / Grass / CRP Forest Grass / Steppe

WEST, Inc.

Most sites in the west have measures of raptor use

12 of these sites have some measure of fatality

R aptors

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

High W

inds , C

A

Altam

ont Pass

, CA

C ottere

l Mtn

., ID

Win

dy F la

ts, W

A

Desert

C laim

, WA

Colum

bia H

ills, W

A

Ha tchett

Rid

ge, CA

Hopkin's R

idge, W

A

White

Cre

ek, WA

Reardon, W

A

Combin

e Hills

, OR

Homest

ead, CA

Rooseve

lt, W

A

Leaning J

uniper,

OR

F oote C

reek R

im, W

Y

Buffalo

Rid

ge, MN

K londik

e, OR

Z inte

l Canyon, W

A

S tate

line , W

A/OR

Maid

en, WA

Condon, OR

Techapi Pass

, CA

Wild

Hors

e , WA

B iglo

w Canyo

n, OR

Nine C

anyon, WA

Dry L

ake, AZ

S an Gorg

onio, C

A

Wind-E nerg y F ac ility

Me

an

us

e

Raptor Use Raptor Fatality

Facilities

High Winds

Diablo Winds

Hopkins Ridge

Klondike

Klondike II

Stateline

Nine Canyon

Foote Creek Rim

Vansycle

Buffalo Ridge

Combine Hills

Range: 0 – 0.14/MW/yr

Three wind projects have

conducted both fatality

monitoring and radar studies

for nocturnal migrants:

Fatality rate/target passage

rate = <0.01%

Buffalo Ridge, MN

Nine Canyon, WA

Stateline, WA/OR

Comparison of Spring Target Rates and

Migrant Fatality Rates

Nocturnal Avian Migration

No large mortality events documented at wind projects

Many species migrate at night and risk to these species is a concern.

Evidence supports ubiquitous nocturnal migration that occurs in variable pulses over time and space – often referred to as “broad-front”.

Altitude and direction of nocturnal migrants variable - probably by species, weather patterns, time of night, season, topography.

Some migrants are at risk of collision with tall structures.

Wildlife Collision Fatality - Bats

appear to be highest at sites on forested ridges in eastern U.S…but…

Recent studies have found higher than expected bat fatalities in open prairie in Alberta…

Mixed agriculture/forest habitats in New York

Regional Bat Fatalities

Bat fatalities have been documented at wind facilities worldwide across a wide range of habitats…

Upper Midwest

hoary

eastern red

silver-haired

eastern pipistrelle

little brown

big brown

Eastern U.S.

hoary

eastern red

silver-haired

eastern pipistrelle

little brown

big brown

other

Pacific Northwest

hoary

silver-haired

little brown

big brown

Rocky Mountain West

hoary

silver-haired

little brown

big brown

Fatalities are skewed to migratory bats, especially tree roosting species

To date, no T&E species have been found, but future is uncertain given projected expansion of wind energy

Eleven of the 45 species north of Mexico have been found killed by turbines

Patterns of Bat Fatality

Only one study in CA and NONE from Texas and most of SW

High proportions of Mexican free-tailed bats found at 2 sites in OK and CA

Mostly pregnant females collected in May and June in OK…located within 10 km maternity cave

Patterns of Bat Fatality

Patterns of Bat Fatality

Fatalities highest in mid-summer-fall, coinciding with migration…

Timing of Bat Mortality

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20 25 30 35 40 45

Study Day

Fa

tali

ty I

nd

ex

meyersdale

mountaineer

Some evidence to suggest regional patterns in timing of fatality…perhaps related to migration, weather or food

Thermal images indicated that bats appear to be attracted to and investigate both moving and non-moving blades

Horn, et al. 2008. Observations of nocturnal activity of bats at wind turbines using infrared thermal imaging. Journal of Wildlife Management 71: 123–132.

Bats may be attracted to turbines

Majority of bats killed in PA, TN, and WV were on low wind nights; kills negatively related to wind speed

Bat kills also associated with lower relative humidity and higher barometric pressure; conditions typical after weather fronts pass2 4 6 8 10

windspeed (m/s)

0.0

0.2

0.4

0.6

0.8

1.0

Fa

talit

ies/t

urb

ine

/nig

ht

Patterns MAY be predictable…need to investigate further and experimentally test curtailment during low wind periods…

Wildlife Collision Fatality - Bats

Species experiencing highest fatalities have little or no protection and are not representative of local species in most cases

Eastern red bats already documented in decline in three mid-western States

(Whitaker et al. 2002, Carter et al. 2003, Winhold et al. 2005)

While population impacts are unknown, considerable concern about cumulative impacts as wind energy expands…

Bat Fatality - Conclusions

Bats are long-lived, slow reproducing mammals… Turbines are killing prime breeding age adults

Possible Explanations Why Bats Are Being Killed by Wind Turbines?

• Linear Corridor

• Roost Attraction

• Landscape Attraction

• Low Wind Velocity

• Heat Attraction

• Visual Attraction

• Acoustic Attraction

• Echolocation Failure

• Electromagnetic-Disorientation

• Decompression

• Thermal Inversion (from Kunz et al. 2007)

Interpreting Fatality Estimates

Important sampling biases:

• carcass removal by scavengers

• searcher efficiency

• vegetation conditions

• fatalities outside of search plots

Interpret estimates of fatality carefully:

• Estimates are conditioned upon the above described factors, and how biases were or were not accounted for

• Estimates are calculated differently for many studies

Others Issues Surrounding Wind and Wildlife

Few peer-reviewed, published studies…although trend is changing

Inconsistent application of scientific methodology

Inconsistent implementation of methods and survey protocols, including quantifying sampling bias

Major issue with passerines and bats is the Context?

How many critters are moving through the airspace in relation to fatality?

Estimating Fatalities

No big surprises with respect to birds where mortality data collected in the area/region

We know a great deal about avian fatality rates in some landscapes (e.g., Ag) and some regions (e.g., PNW)

Lack of replication of fatality studies, particularly in the northeast for birds and nationally for bats (ongoing studies will be valuable additions)

Lack of information in some areas already developed (e.g. SW) and proposed for development (e.g. coastal)

Limited studies with pre-construction diurnal avian and bat use data and post-construction fatality limit predictive ability Raptor use and mortality appear to be related

Fatality Estimation (continued)

Reliability of predictors are being tested with fatality data, bats are a major uncertainty

Better predictions will occur with more fatality data and data on influencing variables

Suggest more emphasis on denominator of risk index (response/exposure = risk)

Different ways to estimate the probability of

availability and detection

Most methods used to date do ok when interval

between searches greater than mean removal

time for carcasses

Modifications forthcoming for the case when

interval is short compared to mean removal time

.

Acknowledgments

Paul Cryan – bat collision history slides

Robert Thresher – several slides on bird

and wind turbine history

WEST colleagues – David Young, Jessica

Kern, Greg Johnson, Wally Erickson

Ed Arnett BCI

Questions?