December 2003 • NREL/SR-500-33829 Bird Risk Behaviors and Fatalities at the Altamont Pass Wind Resource Area Period of Performance: March 1998–December 2000 C.G. Thelander, K.S. Smallwood, and L. Rugge BioResource Consultants Ojai, California National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute • Battelle Contract No. DE-AC36-99-GO10337 December 2003 • NREL/SR-500-33829 Bird Risk Behaviors and Fatalities at the Altamont Pass Wind Resource Area Period of Performance: March 1998–December 2000 C.G. Thelander, K.S. Smallwood, and L. Rugge BioResource Consultants Ojai, California NREL Technical Monitor: K. Sinclair Prepared under Subcontract No. LAT-1-30222-01 National Renewable Energy Laboratory 1617 Cole Boulevard Golden, Colorado 80401-3393 NREL is a U.S. Department of Energy Laboratory Operated by Midwest Research Institute • Battelle Contract No. DE-AC36-99-GO10337 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. 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Box 62 Oak Ridge, TN 37831-0062 phone: 865.576.8401 fax: 865.576.5728 email: [email protected] Available for sale to the public, in paper, from: U.S. Department of Commerce National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 phone: 800.553.6847 fax: 703.605.6900 email: [email protected] online ordering: http://www.ntis.gov/ordering.htm Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste TABLE OF CONTENTS EXECUTIVE SUMMARY...............................................................................................................1 1.0 INTRODUCTION ......................................................................................................................2 1.1 Natural Behaviors and Ecological Relationships: Sensitivity...............................................3 1.2 Exposure to Wind Farm Operations: Vulnerability...............................................................4 1.2.1 Wind Tower Design, Location, and Operation ...............................................................4 1.2.2 Altered Prey Availability..................................................................................................5 1.3 Measuring Effects on Birds: Impacts.....................................................................................6 1.4 Relating Impacts to Causal Variables: Predictions and Solutions ........................................7 2.0 OBJECTIVES .............................................................................................................................8 3.0 STUDY AREA ...........................................................................................................................8 4.0 METHODS..................................................................................................................................9 4.1 Study Plots and Wind Energy Facilities Sampled................................................................9 4.2 Bird Fatalities..........................................................................................................................9 4.2.1 Scavenging Activities....................................................................................................11 4.3 Bird Behaviors ......................................................................................................................12 4.3.1 Observer Bias.................................................................................................................14 4.4 Landscape Features...............................................................................................................14 4.5 Burrowing Rodents...............................................................................................................15 5.0 PRELIMINARY RESULTS .....................................................................................................16 5.1 Bird Use.................................................................................................................................16 5.2 Bird Behaviors ......................................................................................................................16 5.3 Fatality Searches ...................................................................................................................18 5.3.1 Scavenging Effects ........................................................................................................19 5.4 Seasonal Use Patterns...........................................................................................................19 5.4.1 Flight Time by Season...................................................................................................19 5.5 Physical Features ..................................................................................................................19 5.5.1 String Size.....................................................................................................................20 5.5.2 Windswept Area ...........................................................................................................20 5.5.3 Tower Type...................................................................................................................20 5.5.4 Rotor Diameter .............................................................................................................20 5.5.5 Rotor Speeds.................................................................................................................21 5.5.6 Tower Height................................................................................................................21 5.5.7 Turbine Position in String ............................................................................................21 5.5.8 Type of Physical Relief ................................................................................................22 5.5.9 Declivity Winds.............................................................................................................22 5.5.10 Canyon Effects............................................................................................................22 5.5.11 Slope Aspect ................................................................................................................23 5.5.12 Additional Features .....................................................................................................23 5.6 Burrowing Rodents...............................................................................................................23 5.6.1 Intra-String Comparisons ..............................................................................................23 5.6.2 Inter-String Comparison................................................................................................24 6.0 DISCUSSION ...........................................................................................................................25 6.1 Summary of Key Findings....................................................................................................27 6.2 Tasks Remaining...................................................................................................................28 6.3 Management Implications ....................................................................................................28 7.0 ACKNOWLEDGEMENTS .....................................................................................................29 8.0 REFERENCES..........................................................................................................................29 9.0 TABLES.....................................................................................................................................33 10.0 FIGURES .................................................................................................................................52 APPENDIX: DATA DICTIONARY..............................................................................................83 ii EXECUTIVE SUMMARY It has been documented that wind turbine operations at the Altamont Pass Wind Resource Area kill large numbers of birds of multiple species, including raptors. We initiated a study that integrates research on bird behaviors, raptor prey availability, turbine design, inter-turbine distribution, landscape attributes, and range management practices to explain the variation