Bird and Bat Movement Patterns and Mortality Montezuma Hills Wind
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Energy Research and Development Division FINAL PROJECT REPORT BIRD AND BAT MOVEMENT PATTERNS AND MORTALITY AT THE MONTEZUMA HILLS WIND RESOURCE AREA Prepared for: California Energy Commission Prepared by: H. T. Harvey & Associates JUNE 2013 CEC‐500‐2013‐015 Prepared by: Primary Author(s): Dave S. Johnston Judd A. Howell Scott B. Terrill Nellie Thorngate Jim Castle Jeff P. Smith H. T. Harvey & Associates 983 University Ave, Building D Los Gatos, California 95032 http://www.harveyecology.com Todd J. Mabee Jonathan H. Plissner Nathan A. Schwab Peter M. Sanzenbacher Corey M. Grinnell ABR, Inc. P.O. Box 249 Forest Grove, Oregon 97116 http://www.abrinc.com Contract Number: PIR-08-027 Prepared for: California Energy Commission John Mathias, Joseph O’Hagan Contract Manager Laurie ten Hope Deputy Director RESEARCH AND DEVELOPMENT DIVISION Robert P. Oglesby Executive Director DISCLAIMER This report was prepared as the result of work sponsored by the California Energy Commission. It does not necessarily represent the views of the Energy Commission, its employees or the State of California. The Energy Commission, the State of California, its employees, contractors and subcontractors make no warranty, express or implied, and assume no legal liability for the information in this report; nor does any party represent that the uses of this information will not infringe upon privately owned rights. This report has not been approved or disapproved by the California Energy Commission nor has the California Energy Commission passed upon the accuracy or adequacy of the information in this report. ACKNOWLEDGEMENTS The authors thank the California Energy Commission for funding this study; PIER staff for making the process easy, especially John Mathias and Linda Spiegel; and Joanie Stewart, Renee Culver and Tom Kelley at NextEra Energy, Andy Linehan (dearly missed), Stewart Webster, Jerry Roppe, and Keith Warner at Iberdrola Renewables, and John Opris at enXco for all aspects of their assistance. The H. T. Harvey authors also thank its tireless field crew for the endless walking over difficult terrain, especially Rob Shields, who was injured in the line of duty; Samantha Moturi for database support and management; and Mark Lagarde for GIS support. The ABR authors also thank Delee Spiesschaert and Susan Cooper for logistical support; Mike Davis, Melinda Malek, and Cris Hein for help with field work; Bill Hepburn for help with engineering the acoustic monitoring system; Pam Odom for report preparation; and Rich Blaha for figure preparation and GIS support. The authors also thank Dr. Shannon Bros from San Jose State University and David Zajanc from H. T. Harvey for statistical guidance and direction. Finally, the authors expressly thank their Professional Advisory Committee, including Dick Anderson, Renee Culver, Jim Estep, Bronwyn Hogan, and William Rainey for their thoughtful comments and oversight during the study. i PREFACE The California Energy Commission Energy Research and Development Division supports public interest energy research and development that will help improve the quality of life in California by bringing environmentally safe, affordable, and reliable energy services and products to the marketplace. The Energy Research and Development Division conducts public interest research, development, and demonstration (RD&D) projects to benefit California. The Energy Research and Development Division strives to conduct the most promising public interest energy research by partnering with RD&D entities, including individuals, businesses, utilities, and public or private research institutions. Energy Research and Development Division funding efforts are focused on the following RD&D program areas: • Buildings End‐Use Energy Efficiency • Energy Innovations Small Grants • Energy‐Related Environmental Research • Energy Systems Integration • Environmentally Preferred Advanced Generation • Industrial/Agricultural/Water End‐Use Energy Efficiency • Renewable Energy Technologies • Transportation Bird and Bat Movement Patterns and Mortality at the Montezuma Hills Wind Resource Area is the final report for the Evaluating the Effectiveness of Avian Interaction Mitigating Measures and Processes Project, Agreement Number PIR‐08‐026 conducted by H. T. Harvey & Associates. The information from this project contributes to PIER’s Energy‐Related Environmental Research Program. For more information about the Energy Research and Development Division, please visit the Energy Commission’s website at www.energy.ca.gov/research/ or contact the Energy Commission at 916‐327‐1551. ii ABSTRACT Birds and bats have become important factors in the siting and permitting of wind‐energy facilities. Identifying methods to avoid, minimize, and mitigate bird and bat fatalities should help streamline wind energy permitting and reduce potential impacts to bird and bat resources. In this study, the authors conducted nighttime surveys to investigate the effectiveness of using horizontal/vertical radar, full‐spectrum acoustic monitoring and night vision to determine nocturnal flight directions, passage rates, and flight altitudes of birds and bats at the Montezuma Hills Wind Resource Area in Northern California. Following nighttime surveys, daily carcass searches were conducted to assess fatality rates as a function of movement patterns in the wind resource area. In addition, the study explored relationships between bird and bat fatalities, relevant activity indices, and the meteorological, landscape, and vegetation features of the study area. Although average nocturnal passage rates ranged from 326—454 targets per kilometer per hour, a high rate in the western United States, only 2–6 percent of the total passed through at altitudes less than the 125 meters above ground level, the height where birds and bats are at risk of collision with wind turbines. Six nocturnal‐migrant bird and 53 bat fatalities were observed during the two 40‐day surveys. Carcass‐detection ratios ranged from 0.20–0.50. Carcass‐removal rate analysis indicated that 45 percent of small bird and 39 percent of bat carcasses disappeared within 24 hours, suggesting that a majority of small bird and bat fatalities would be missed by the weekly surveys that are commonly conducted. The total number of nocturnal migrant bird fatalities was quite low relative to the passage rate, indicating that this wind resource area is relatively benign with respect to migrating birds. Overall, the three detection methods (radar, night‐vision, and acoustic) helped to provide a comprehensive and detailed view of the species inhabiting the night skies over the study area. In particular, this study identified that using altitude‐specific radar in the high‐risk zone can be a useful tool for monitoring fatality risk for birds in this wind resource area. Keywords: Wind energy wildlife impacts, Montezuma Hills, hoary bats, Mexican free‐tailed bats, migrant passage rates, migrant passage altitudes, bat fatalities, bird fatalities, carcass removal trials, spatial relationships of wind turbine fatalities Please use the following citation for this report: Johnston, Dave S., Judd A. Howell, Scott B. Terrill, Nellie Thorngate, Jim Castle, Jeff P. Smith (H. T. Harvey & Associates), Todd J. Mabee, Jonathan H. Plissner, Nathan A. Schwab, Peter M. Sanzenbacher, and Corey M. Grinnell (ABR, Inc.). 2013. Bird and Bat Movement Patterns and Mortality at the Montezuma Hills Wind Resource Area. California Energy Commission. Publication Number: CEC‐500‐2013‐015. iii TABLE OF CONTENTS Acknowledgements ................................................................................................................................... i PREFACE ................................................................................................................................................... ii ABSTRACT .............................................................................................................................................. iii TABLE OF CONTENTS ......................................................................................................................... iv LIST OF TABLES .................................................................................................................................... vi LIST OF TABLES .................................................................................................................................. viii EXECUTIVE SUMMARY ........................................................................................................................ 1 Introduction ............................................................................................................................................ 1 Purpose .................................................................................................................................................... 1 Objectives ................................................................................................................................................ 2 Conclusions and Recommendations ................................................................................................... 2 Benefits to California ............................................................................................................................. 4 CHAPTER 1: Introduction ....................................................................................................................... 6 1.1 Project Objectives ....................................................................................................................