Offshore Wind Farm Placement Conditioned by Bird Migration Study (USA)

Scientists from the BioDiversity Research Institute in Gorham have documented what they say is a significant migratory pathway for several species of falcons and northern saw-whet owls. The new study could have a bearing on where and how off-shore wind projects are sited in the future.

Every spring and fall, thousands of eagles, falcons, hawks and other raptors travel along the Atlantic coast, including Maine, between their breeding and wintering areas. Some of the distances they fly are as far apart as Greenland and Argentina.

And while migration routes have been well studied inland, wildlife research biologist Chris DeSorbo of the BioDiversity Research Institute says few efforts have been made to monitor the migration of raptors 10 miles or more off-shore.

So this fall, DeSorbo and his colleagues from BRI set up a falcon research station at Monhegan Island and seven owl research stations from Lubec to Cape Elizabeth to determine whether these birds of prey were moving along the Maine coast.

“We counted over 800 raptors, just under 400 of which were merlins–these are small, dark falcons that most people don’t really ever see,” DeSorbo says. “And then you see a pulse of other birds, like peregrine falcons, which are widely known as the fastest animal on the planet. They have a long conservation history of basically being on the brink of extinction and rebounding.”

During the course of four weeks, DeSorbo and his team learned that most of the falcons arrive around the beginning of October. They also collected information about the birds’ migratory path leaving the area.

“That will be very useful in windpower siting decisions because basically we’re trying to collect information that would be helpful for lawmakers, policymakers, the general public to decide where wind farms should be placed and have some pre-construction information.”

Last year, the waters offshore of Monhegan Island were selected by the state as one of three test sites for offshore wind energy development. The Monhegan project will be undertaken by the DeepC Wind Consortium, a group of University of Maine academics and private business interests.

“Part of the permitting for that test site deals with monitoring bird and bat migrations; the potential impact of the test site on those animals and other marine animals in the area,” says David Farmer, a spokesman for Gov. John Baldacci, who has been an advocate of offshore wind development.

“The goal is to gather information at the test site that will lead to better development of technology and the permitting process for offshore, deepwater windpower,” Farmer says.

One species that BRI wildlife biologist Kate Williams says has been overlooked in many monitoring studies is the owl. That’s why BRI also set up eight monitoring locations in coastal Maine for northern saw-whet owls, which migrate at night.

Williams says all told, 253 owls were counted. “It actually wasn’t widely known that they flew over large bodies of water. We caught them everywhere we tried, including several offshore islands. And in fact, the highest rate of capture for owls at any of our sites was on Vinylhaven Island.”

In addition to counting birds, the BRI team also attached satellite transmitters to two peregrine falcons, which will allow biologists to follow the birds’ travels over the next year. So far the two birds have traveled more than 6,400 combined miles and are currently in Cuba and Columbia. Their migration will be regularly updated on the BioDversity Research Institute Web site.

BRI’s research was funded by the Davis Conservation Foundation, an anonymous charitable foundation, and a Maine Outdoor Heritage Fund grant sponsored by the Maine Department of Inland Fisheries and Wildlife.

By Susan Sharon (mpbn)

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Source: mpbn, December 22, 2010