Bird migration study entering fall phase 

A multi-agency study of the flight patterns of migratory birds along the Lake Erie shoreline – and if the patterns would place flocks dangerously close to wind turbines – will enter its next phase with the expected arrival this week of more radar equipment at the Black Swamp Bird Observatory near Oak Harbor.

Mark Shieldcastle, the observatory’s research director, said the U.S. Geological Service is providing two radar units and Bowling Green State University is providing another for the study, which will also include personnel from the U.S. Fish and Wildlife Service, The Ohio State University, University of Toledo, and the observatory.

He said the radar units will be used to help track patterns of movement and volume of the birds, their elevation, and how they’re interacting with the lake and shoreline.

“We want to know how high are they? Are they above the risk zone?” Shieldcastle said, referring to the area around wind turbines that pose a danger for migrating birds.

The BGSU unit will likely be positioned along the shoreline at the Ottawa National Wildlife Refuge while one of the USGS units will be near the Davis-Besse power plant and the other will moved to various sites between three and 15 miles from the shoreline.

Radar has been used to study flight patterns in the spring, Shieldcastle said, but the patterns are different in the autumn.

“Ultimately we hope to have a third USGS unit here so they can look at the coast area from three miles and 15 miles at the same time,” he said. “The plan is to look at both spring and fall migration this year and next year so we can have two years worth of data. Fall migration and spring migration can be very different in how the birds react to the lake. The lake is a barrier and the small land birds don’t want to cross open water.

“We see much larger concentrations of birds in the spring than we do in the fall even though there should be more birds in the fall. But they could be coming across and taking longer to settle in. We don’t know what we’ll see.”

Shieldcastle and the BSBO hosted a coalition of researchers from universities, government, and conservation groups in February in a forum to update their peers on projects they’ve undertaken in the Great Lakes region. The participants also discussed the most cost-effective ways of incorporating additional radar units into a comprehensive migration study program that would include banding, counts, and acoustic monitoring.

The coalition renewed its call for additional study of flight patterns along the lake before wind energy development is pursued. Researchers have called for a three-year moratorium on the placement of wind turbines within three miles of Lake Erie in Lucas, Ottawa, Sandusky, and Erie counties until adequate radar studies can be conducted on their impact.

Shieldcastle said there is a need for more data about the angle of descent and ascent of birds that stop to rest and feed along the shore during migration.

Although there has been research on the effect of wind turbines on migratory birds, most of those studies have been conducted in areas where birds are in active migration – with some portion of the flocks flying well above turbine blades.

But the study of flight patterns of flocks approaching or leaving stop-over habitat is more challenging, Shieldcastle said, because many songbirds are nocturnal migrants, landing and taking off during the night when visibility is poor for the birds and researchers.