The Oregon State team, working with federal, industry, and nonprofit partners and funded in part by the Oregon Legislature, builds on a Norwegian study that found painting one turbine blade black reduced bird collisions by nearly 72%.

“This was a dramatic effect, but it was a relatively small sample size,” said Christian Hagen, senior research faculty in Oregon State’s Department of Fisheries, Wildlife, and Conservation Sciences. “Industry and scientists in North America felt that before this became a policy change, we should replicate, enlarge the sample size, and analyze different bird species to ensure it is effective and that there aren’t any negative effects.”

Twenty-eight turbine blades at a PacifiCorp wind farm near Glenrock, Wyoming, have been painted black for the study. Researchers aim to assess whether painted blades reduce fatalities among eagles, other birds, and bats.

The hypothesis suggests black-painted blades disrupt the visual uniformity of the airspace, making turbines more noticeable to birds and prompting avoidance. While daytime-active birds like eagles may detect the painted blades, bats, relying on auditory cues and different visual abilities, may not respond similarly.

Hagen joined the project after the Oregon Legislature allocated $400,000 in 2021 to study black-painted blades. PacifiCorp’s involvement provided an ideal research site.

Hagen and doctoral student Natia Javakhishvili are developing a model using bird movement data to evaluate bird avoidance around painted turbines. Javakhishvili is focusing on golden eagles, leveraging a dataset with eight million movement points to improve model accuracy.

“This study is particularly rigorous and comprehensive due to its incorporation of altitude as a third dimension in the analysis, capturing vertical flight dynamics often overlooked in traditional studies,” Javakhishvili said.

At the Wyoming site, researchers and detection dogs search for bird and bat carcasses to help predict the population-level impact of wind energy on species like ferruginous hawks, native to western North America.

Hagen said the findings, expected in the coming years, will guide wind energy companies and state and federal agencies in reducing bird collisions. Many affected bird species are protected under federal laws, including the Migratory Bird Treaty Act and the Bald and Golden Eagle Protection Act.

Similar studies are underway in Spain, Sweden, and South Africa. Other project partners include the U.S. Geological Survey, U.S. Fish and Wildlife Service, U.S. Department of Energy, Renewable Energy Wildlife Institute, Invenergy, and NextEra Energy Resources.

This story was originally published by Oregon Stat University and can be viewed here.