By MICHELE F. MIHALJEVICH

Indiana Correspondent

MOLINE, Ill. — Research aimed at the conservation of bald eagles in the upper Midwest may help wind companies design their wind farms to provide protection for the birds, according to researchers working on the project.

Wind energy companies are among those interested in the results of the ongoing study, noted Trish Miller, executive director and research wildlife biologist for Conservation Science Global, Inc. The organization is collaborating with the U.S. Geological Survey (USGS) to provide information to the U.S. Fish and Wildlife Service (FWS) and wind energy developers and operators.

“We’re trying to fill in a knowledge gap,” she explained. “We’re trying to understand what the flight behaviors are that create risk for bald eagles. (Wind companies) don’t want to be killing eagles, either.”

Miller and Todd Katzner, a research wildlife biologist with USGS, are studying bald eagle movement patterns in Illinois, Iowa and Missouri.

“We’re looking at bald eagle movement, how they’re using the landscape, to better understand their risk of colliding with wind turbines in the Midwest,” Miller said. “Bald eagle populations have rebounded with gusto. More wind farms are also going up across the Midwest landscape.”

As more turbines have been placed, there have been a number of collisions, Katzner said. “At a very large scale we know large soaring birds of prey are at risk from some wind turbines,” he pointed out.

“We are trying to use scientific information to guide construction of these wind farms. We want to provide information that can be used so that eagles are not greatly affected (by them).”

The study began six years ago with a small grant. The birds are monitored by backpack telemetry units generally weighing 2-2.5 ounces. The units record eagle locations every six seconds to 15 minutes. During the first part of the study, the researchers concentrated on tagging wintering birds; for the last three years, they’ve also tagged nestlings (those 7-9 weeks old).

The units track where the bald eagles are flying, how high and how fast. Miller and Katzner take that information and match it up to the landscape. About 70 bald eagles have been tagged and approximately 45 units remain active, Miller said.

“Some of those birds either died or disappeared,” she explained. “The units operate on a cell phone network. Maybe the batteries died, the units stopped working or the birds flew out of the cell phone coverage area.”

The researchers are in the process of assessing the information gathered from the telemetry units. “We’re looking to identify risky areas for bald eagles. We’re also identifying times when bald eagles use upland areas, which are where most turbines are located.

“When do they travel to those areas? We’re also looking at what’s driving these movements. We’re trying to create models of risk. We’re looking at how landscape and weather affect how high they’re flying,” she added.

The height of a wind turbine and length of the blades are based on how many megawatts the turbine should produce. Turbines and blades are generally 240-450 feet off the ground, which would be the danger area for bald eagles.

“If they fly in and out of that danger area depends on what they’re doing,” she said. “If they’re hunting, they’re flying lower. It also depends on the time of the year and the topography.”

Studies done with golden eagles have shown when birds fly over a ridge line, they’re flying at lower altitudes, Katzner said. This may suggest that one way to mitigate risk is to offset the turbines from the ridge line and not place them right along it.

In many cases, bald eagles do fly around wind turbines, Miller said. “If they’re in a fight or chasing, feeding or hunting, they can get distracted. They haven’t evolved to understand the danger of spinning blades.”

Wind energy companies take the safety of birds – including bald eagles – seriously, said Peder Mewis, western regional policy manager for the Clean Grid Alliance. “The industry has learned a lot. It recognizes it’s extremely infrequent for these fatalities to occur. But nobody wants any wildlife to be impacted.”

The FWS issued voluntary guidelines for protecting eagles in 2013. “The Eagle Conservation Plan Guidance calls for wind project developers to take a staged approach to siting new projects,” the agency stated.

“(It calls) for preliminary landscape-level assessments to assess potential wildlife interactions and proceed to site-specific surveys and risk assessments prior to construction. (It calls) for monitoring project operations and reporting eagle fatalities to the service and state and tribal wildlife agencies.”