Wildlife Mortality at Wind Facilities: How We Know What We Know How We Might Mislead Ourselves, and How We Set Our Future Course
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To accurately estimate per turbine – or per megawatt – annual wildlife mortality at wind facilities, the raw counts of carcasses found must be adjusted for four major sources of imperfect detection: (1) fatalities that occur outside the monitoring period; (2) carcasses that land outside the monitored area; (3) carcasses that are removed by scavengers or deteriorate beyond recognition prior to detection; and (4) carcasses that remain undiscovered by searchers even when present. To accurately estimate regional or national annual wildlife mortality, data must come from a representative (or appropriately weighted) sample of facilities for which estimates of mortality account for all sources of imperfect detection. I argue that the currently available data in the United States and much of the world do not represent the impacts of wind power on wildlife because not all facilities conduct monitoring studies, not all study results are publicly available, and few studies adequately account for imperfect detection. I present examples illustrating the limitations of our current data and pitfalls of interpreting data without accurately adjusting for detection bias. I close by proposing a solution through a simplified monitoring process that can be applied at every facility as part of normal operations. Application of an unbiased estimator that accounts for all sources of imperfect detection would assure comparability of mortality estimates. Public access to reported estimates would achieve representation. With these data we could develop a clearer understanding of how wind power is affecting wildlife throughout the world and inform our efforts to address it.
KeywordsRepresentative Spatial distribution Road and pad searches R&P Detection probability
I thank the organizing committee of the Conference on Wind Wildlife for inviting me to give this talk and supporting my travel. I thank Fränzi Korner-Nievergelt, Mona Khalil, and an anonymous reviewer for helpful suggestions to improve the manuscript. I thank Dan Dalthorp, Guillaume Marchais, Cris Hein, Michael Schirmacher, and Jerry Roppe, for many fruitful discussions regarding the feasibility of road and pad searches, but do not wish to imply any endorsement on their part of the ideas I present here. Funding for this research was provided by the Ecosystems Mission Area Wildlife Program of the US Geological Survey (USGS). Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US Government.
- 2.Orloff, S., Flannery, A.: Wind Turbine Effects on Avian Activity, Habitat Use, and Mortality in Altamont Pass and Solano County Wind Resource Areas, 1989–1991 In: vol. 23 May 2008. California Energy Commission, Sacramento (1992)Google Scholar
- 6.Arnett, E.B., Brown, K.W., Erickson, W.P., Feidler, J.K., Hamilton, B.L., Henry, T.H., Jain, A., Johnson, G.D., Kerns, J., Koford, R.R., Nicholson, C.P., O’Connell, T.J., Piorkowski, M.D., Tankersley Jr., R.D.: Patterns of bat fatalities at wind energy facilities in North America. J. Wildl. Manag. 72, 61–78 (2008)CrossRefGoogle Scholar
- 8.Scargle, J.D.: Publication bias: the “file drawer” problem in scientific inference. J. Sci. Explor. 14(1), 91–106 (2000)Google Scholar
- 14.Erickson, W.P., Kronner, K., Gritski, B.: Stateline Wind Project Wildlife Monitoring Final Report July 2001–December 2003. In: WEST, Inc., p. 98. FPL Energy, Cheyenne (2004)Google Scholar
- 15.Grodsky, S.M., Drake, D.: Assessing Bird and Bat Mortality at the Forward Energy Center in Southeastern Wisconsin. In: vol. PSC Ref#: 152052. Forward Energy LLC, Chicago (2011)Google Scholar
- 16.Roosevelt, T.: Citizenship in a Republic. Paper presented at the delivered at the Sorbonne, Paris, France (1910)Google Scholar
- 18.Wolpert, R.: Appendix B: a partially periodic equation for estimating avian mortality rates. In: Warren-Hicks, W., Newman, J., Wolpert, R., Karas, B., Tran, L. (eds.) Improving Methods for Estimating Fatality of Birds and Bats at Wind Energy Facilities, CEC-500-2012-086, pp. A1–A20. California Wind Energy Association, Berkely (2013)Google Scholar
- 19.Hein, C., Huso, M.M.P.: Challenges and opportunities of accurately and precisely estimating fatality of birds and bats at wind. Paper presented at the Ecological Society of America, Portland, OR, USA, Aug 6–11 (2017)Google Scholar
- 20.Finney, D.J.: Statistical Method in Biological Assay. Charles Griffin & Co. Ltd, London (1952)Google Scholar