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Webinar on Improving Methods for Estimating Fatality
of Birds and Bats at Wind Energy Facilities


The slides from the webinar presentation made on September 26, 2012 are available here. A link to the webinar recording will be posted on this website in the coming weeks. The final report will be posted on this website by November.

Presenters: Bill Warren-Hicks, Ph.D., EcoStat Inc./Cardno Entrix, Robert Wolpert, Ph.D., Duke University, and Jim Newman, Ph.D., Normandeau Associates

This webinar will present results from a CalWEA-sponsored, California Energy Commission-funded study to increase the accuracy of methods for estimating the number of bird and bat fatalities associated with wind energy facilities, including an improved equation developed to adjust mortality observations. Presenters will review new data on the time-dependency of the probability of bird and bat scavenging and removal (carcass persistence) and detection by searchers (searcher proficiency), as well as assumptions and bias of four existing fatality estimation equations. Focusing primarily on small birds and bats, the study offers important insights and implications for experimental designs and field monitoring recommendations at wind facilities.

Carcass size is a key variable that influences both searcher proficiency and carcass persistence. Bats are harder to find than birds, and all carcasses have low searcher proficiency after three weeks. The new finding of increased persistence of bats relative to birds may not be expected based on the current literature, and, coupled with the lower detection rates of bats than birds, could lead to gross error in expected bat mortality.

Of the equations evaluated, two consistently under-estimated the "true" mortality but the two most commonly used equations typically over-estimated the actual number of carcasses, particularly with daily and weekly search intervals. The degree of error, ranging from -89% to + 158% for datasets with daily searches, is a function of the uncertainty in the average persistence time and removal rate for a fixed interval. Webinar participants will learn why the search interval selection is such a critical factor in estimation procedures, and how rigorous site-specific trials in various environmental conditions are needed to generate carcass persistence and searcher proficiency curves that will minimize bias in the estimated true mortality. Presenters will discuss the merits of conducting the trials at multiple times throughout the year in order to capture the interaction of carcass age and seasonal environmental changes on searcher proficiency.

Dr. William J. Warren-Hicks is CEO of EcoStat, Inc, a small company he co-founded in 2004. He recently joined Cardno Entrix as Technical Director and Vice President / Biostatistics Practice Leader. He holds a Ph.D. from Duke University in environmental statistics. He has 30 years of experience providing consulting expertise in the areas of environmental data analysis, uncertainty analysis, Bayesian inference and decision, probabilistic risk methods, survey design, time-series modeling, messy data analysis, hypothesis testing, multivariate analyses, and model validation studies. Dr. Warren-Hicks is the co-editor of two books on uncertainty analysis, and has authored over 120 peer-reviewed publications addressing the application of probability and statistics in water, air, and terrestrial systems.

Dr. Robert Wolpert is Professor of Statistical Science and Professor of Environmental Sciences & Policy at Duke University, with external appointments in Mathematics at Queensland University of Technology in Brisbane, Australia and in Epidemiology at Imperial College in London, UK. He is known for his work on probability theory and the foundations of both Bayesian and Frequentist Statistical Science. He is known for developing new methodology, modeling, and computational approaches in a range of application areas including biodiversity, ecology, geophysics, partical physics, and meta-analysis. He is Elected Fellow of the American Statistical Association and the Institute of Mathematical Statistics, and winner of the 2002 IMS Medallion Award.

Dr. James R. Newman is Principal Scientist at Normandeau Associates, Inc. He holds a Ph.D. in Zoology with a major concentration in ornithology and animal behavior from the University of California at Davis. He has 36 years' experience in managing and conducting research on the effects of wind and conventional energy generation on wildlife. He has been an active member of the National Wind Coordinating Committee's (NWCC) Wildlife Workgroup and its Risk Assessment Subgroup, co-authoring the NWCC white paper, Ecological Risk Assessment: A Framework for Wildlife Assessments At Wind Energy Facilities. Dr. Newman has been principal scientist and co-developer on several qualitative and quantitative avian risk assessments for on-shore projects in Florida, New York, Iowa, Texas, North and South Dakota, California and off-shore projects in the Atlantic Continental Shelf. Dr. Newman co-authored for the New York State Energy Research and Development Authority (NYSERDA) a life cycle evaluation of effects of electricity generation including wind energy on wildlife.

Fast Facts about California Wind Energy

+ Wind energy projects totaling approximately 5,812 megawatts (MW) of capacity are operating in California today,1 providing enough electricity to power more than 2 million California households.2 This represents more than a tripling of wind energy capacity since California's Renewables Portfolio Standard (RPS) law was adopted in 2002.

+ In 2012, California wind projects generated 9,152 gigawatt-hours (GWh) of electricity - 4.6% of all power generated within California.3 In the same year, out-of-state wind projects generated 9,983 GWh of electricity for California, representing 10% of total power imports.3 Combined, wind projects supplied 6.3% of California's total system power,3 enough to power all homes in Sacramento, Santa Clara, and San Diego Counties combined.2

+ CalWEA expects wind energy to provide close to 7% of California's electricity supply in 2014.

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