Avoidance of Wind Generators by Breeding Grassland Birds

1. Avoidance of Wind Generators by Breeding Grassland Birds Jill A. Shaffer1, Douglas H. Johnson2, Deborah A. Buhl1 1USGS Northern Prairie Wildlife Research Center, Jamestown, ND; 2USGS NPWRC, St. Paul, MN Results: Species that exhibited attraction or for which results were inconclusive Summary: Strong evidence for the avoidance of wind generators up to 250 m across sites and years occurred for Grasshopper Sparrow. Moderate evidence for avoidance occurred for Clay-colored Sparrow up to 250 m. No evidence for avoidance or attraction was detected for Savannah Sparrow. Bobolink, Chestnut-collared Longspur, and Western Meadowlark were not consistent. In some years, evidence for avoidance occurred, but in other years, no evidence for avoidance or attraction was detected. Due to low numbers of individuals observed, results were inconclusive for Upland Sandpiper. Killdeer showed attraction up to 50 m at 1 site for 1 year; results were inconclusive for other years and at other sites. Statistical Methods: Likelihood Ratio Statistic Attraction Distance • We compared the observed distribution of minimum distances to expected distances under the assumption of a no-displacement effect. • For every d(where d = 50, 100, 150, …, 1000 m), the number of birds within distance d of a wind generator, as well as the number beyond d,were tallied. The observed distribution for every d was compared to the expected distribution using a likelihood ratio test (g2). The d with the highest ratio was considered the distance up to which attraction or avoidance was occurring. 0 50 SD Wind 2004 Distance (m) from wind generators Killdeer (KILL) Introduction Results: Species that exhibited avoidance in some site / year combinations Construction of new wind-energy facilities is occurring exponentially. The U.S. Department of Energy predicts that wind energy could provide 20% of the United States’ electrical supply by 2030. However, natural-resource professionals are concerned about the effects of wind developments on wildlife, specifically the impacts from avoidance and mortality. Northern Prairie Wildlife Research Center is conducting a long-term (>10 yr) study that evaluates the avoidance of wind generators by grassland birds in native grasslands. Savannah Sparrow (SAVS) Number of individuals observed were insufficient to determine avoidance or attraction for Upland Sandpiper and some Killdeer site/year combinations. No evidence for avoidance or attraction was detected for Savannah Sparrow. Upland Sandpiper (UPSA) Avoidance Distance 0 Bobolink (BOBO) Avoidance in 2 of 5 site / yrs Conclusions Objective: Do grassland birds avoid wind facilities? = We examined results pre- and post-treatment, and by species, site, and year. Pre-treatment, we detected no avoidance or attraction to locations where wind generators were to be placed. Of the 4 species that occurred on all 3 study sites (GRSP, KILL, UPSA, WEME), only GRSP showed consistent post-treatment avoidance among all sites and all years. Avoidance occurred most often within 100 – 200 m of generators. Due to low number of individuals observed, data were inconclusive for KILL at 2 sites and for UPSA at all sites. At the SD site for 1 year, KILL showed attraction within 50 m, probably due to gravel roads that connect generators. WEME was neutral at Tatanka, exhibited avoidance at Oliver for the second of 3 post-treatment years and was neutral thereafter, and exhibited avoidance in the first of 5 post-treatment years at the SD site; this species may acclimate to the presence of wind generators. BOBO occurred at both the Oliver and Tatanka sites; for 1 year at each site, the species exhibited avoidance up to 200 m. CCLO in SD showed evidence for avoidance for 2 of 5 years, up to 150 m. CCSP showed evidence for avoidance at Oliver for all 3 years, up to 250 m. No evidence for avoidance at Tatanka was detected for SAVS. This study was conducted to determine whether grassland breeding birds in native, mixed-grass prairie in North and South Dakota avoid wind generators. 50 Tatanka 2009 Tatanka 2010 Wind Facilities Studied in ND and SD Chestnut-collared Longspur (CCLO) Avoidance in 2 of 5 site / yrs = SD Wind 2005 100 SD Wind 2004 Clay-colored Sparrow (CCSP) Avoidance in 3 of 3 site / yrs = SD Wind 2008 Oliver 2011 150 SD Wind 2004 SD Wind 2005 Oliver 2007 Oliver 2009 Acknowledgments Bird and Vegetation Methods Grasshopper Sparrow (GRSP) Avoidance in 10 of 10 site / yrs Tatanka 2009 Oliver 2007 = Oliver 2009 We thank USGS and NextEra Energy (NEE) for funding the study and USFWS for logistical and technical support. Permission to access wind facilities was granted by NEE, Acciona, and BP Alternatives. Many thanks to landowners and USFWS for land access and to the field technicians for their long field days. Photo credits go to S. Stucker, VIREO, and J. Wantulok. The assistance of B. Euliss was indispensable. 200 • Each wind facility had ≥ 3 rows of generators and 3 control areas. • We established survey grids of 50 x 250-m cells that encompassed a row of generators out to 0.8 km (0.5 mi)from all sides of the row, as long as habitat was grazed, mixed-grass prairie. • We conducted total-area bird surveys within the grids. • We recorded locations of birds relative to generators so as to determine distance of each bird to the nearest generator. • We mapped wetlands and woodlands in order to exclude areas of habitat unsuitable for grassland birds. SD Wind 2006 SD Wind 2010 Oliver 2009 Oliver 2011 Contact Information Western Meadowlark (WEME) Avoidance in 2 of 10 site / yrs = Oliver 2007 Site/year combinations not represented above were neutral, meaning that at sufficient sample sizes, no evidence for avoidance or attraction was detected. None of the species above exhibited attraction. Jill Shaffer or Douglas Johnson USGS Northern Prairie Wildlife Research Center Shaffer: 701-253-5547; jshaffer@usgs.gov Johnson: 612-624-4716; Douglas_H_Johnson@usgs.gov 250 SD Wind 2008 Distance (m) from wind generators