Methods • Titan I Wind Farm consists of a single string of 10 2.5-MW turbines in Hand County, SD

situated within the whooping crane migration corridor

• BP Wind Energy currently is conducting 3 years of on-site post-construction whooping crane monitoring

• Crane monitor is onsite daily from approximately March – May and September – November in each study year

• Crane monitor drives accessible roads within and surrounding the facility, focusing on wetlands and high points for maximum viewshed

• Crane monitor watches for whooping cranes specifically; records behavior of all cranes flying in proximity to turbines

• Sandhill cranes used as surrogates for whooping crane flight behavior due to propensity of whooping cranes to migrate with flocks of sandhill cranes; data collected includes flight paths of crane flocks, behavioral data including flight height and flight direction

• If whooping cranes are observed within a 3.2 km buffer of turbines, monitor notifies operations center to curtail turbines; if whooping cranes are onsite or within the 3.2 km buffer, monitor remains with the whooping cranes until they leave the site

Laura Nagy, Natural Resources Discipline Lead Email: Laura.Nagy@tetratech.com Office: (503) 721-7214, Cell: (503) 367-1627 Crane photos: Doug Backlund, dougback@wildphotosphotography.com

Introduction • Understanding if wind energy projects pose risk to migrating whooping cranes has

implications for both wind energy development within the whooping crane corridor and management of a federally endangered species

• Primary risk factors to cranes include risk of turbine and power line collision and loss or modification of migratory stopover habitat

• Crane behavioral response to turbines is poorly understood; this study represents one company’s commitment to understanding this response

Objectives • To evaluate potential avoidance and risk to cranes of an operational wind facility

• To determine if migrating cranes flying above or within the height of the rotor-swept area (RSA) alter their behavior due to the presence of the turbines

• To implement a protocol for turbine curtailment when whooping cranes are within 3.2 km of turbines

Laura Nagy1, Brandy Gibson2, Karl Kosciuch1, Jennifer Taylor1, Blayne Gunderman2 1Tetra Tech and 2BP Wind Energy

Results—Sandhill Cranes • 11,330 sandhill cranes were detected flying over, around and through the

turbine string in spring and fall (Table 1, Table 2) • Sandhill cranes altered flight trajectory away from turbines when flying within

the height of the RSA more often than when flying above the RSA (Figure 2) • Sandhill cranes showed a tendency not to alter flight trajectory when flying

within the height of the RSA when approaching the area with the greatest spacing between turbines (1,085 m separation distance; Figure 2)

• During stopover periods, sandhill cranes were observed as close as 790 m from the nearest turbine

Table 1. Sandhill Crane Behavior at the Titan I Wind Farm

1Flock size ranged from 1 – 418 individuals

2Two flocks of sandhill cranes had short flight paths, landed within vicinity and were not included in analysis 3Data in 2012 represent spring only

Conclusions & Implications • Whooping crane flight behaviors did not create a risk of

collision in either season

• Whooping and sandhill cranes appear to have low risk of collision with wind turbines due to their ability to avoid turbines by flying over, around or through gaps within a turbine string

• These data suggest that risk of turbine collision is minimal due to crane migratory flight behavior (tendency to fly above the height of the RSA) when turbines are visible; collision risk may increase when visibility is reduced due to weather conditions or topography

• Likely low energetic cost of avoidance behavior at the Titan I Wind Farm

• Additional studies are needed to evaluate how turbine spacing influences crane collision risk and avoidance behavior

Year

Flight height relative to

RSA

Crane flocks altered

flight trajectory

(avoided)

Cranes continued

flight path (did not

avoid)

Crane flight path not

directly through wind

farm

20102 Within 11 1 1 Above 12 34 1

2011

Within 3 0 2 Above 12 35 9

20123 Within 3 - - Above 21 42 4

Results—Whooping Cranes • Whooping cranes were observed in Spring and Fall 2010; no whooping cranes

observed in 2011 or in Spring 2012; Fall 2012 monitoring ongoing

• Spring 2010: flock of 5 whooping cranes utilized stopover habitat within 1.9 km of turbines for 3 days; turbines were within line-of-sight at some stopover locations (Figure 1)

• Fall 2010: two flocks of 2 and 3 whooping cranes observed flying at RSA height on a trajectory to the west of the wind farm, but within 500 m of the terminal turbine (Figure 1); cranes displayed migratory flight; no stopover occurred

• Turbine curtailment in response to whooping crane presence in both seasons

Table 2. Sandhill Crane Observations at the Titan I Wind Farm

Figure 1. Whooping crane flight paths in Spring and Fall 2010

Year

Spring Fall All Seasons Total

flocks Total birds

Total flocks

Total birds

Total flocks

Total birds

2010 17 1,387 45 2,580 62 3,967 2011 21 719 40 3,089 61 3,808 2012 70 3,555 - - 70 3,555

Grand Total 108 5,661 85 5,669 123 11,330