Mitigating windmills' threat to birds
Like most environmentally enlightened birders, I'm excited by the prospect of erecting a string of colossal power-producing windmills in Lake Erie.
Wind is infinite and plentiful on the lake, and immeasurably cleaner than coal-burning power plants. Birders know better than most the terrible impact on birds of acid rain, mercury and global warming.
But I'm concerned about a basic premise of the environmental engineering consultant who prepared a comprehensive Avian Risk Assessment report.
The report downplays the dangers the windmills would pose to migrating songbirds, citing radar and studies that indicate nocturnal migration occurs mostly at altitudes above the height of wind turbines, thus fatality rates of migrating songbirds would be negligible.
That would be wonderful, if true.
But what if the birds dip into the blades of the windmills? The giant fans would reach as high as 500 feet -- or about 50 stories -- into the air. That is a spinning structure comparable to the two tallest skyscrapers in Cleveland: the 45-story BP building and the 57-story Key Tower, the tallest building in Ohio.
I recall standing with a crowd of birders on a pier at the Lakeside resort in September 2007, rapt in amazement as the faint flight calls of warblers, thrush and bobolinks rained down from above, sounding as if they were no more than an arms length away.
I'm reminded of waves of songbirds streaming across the Gulf of Mexico, flying barely above the white-caps, and plunging exhausted into the woods at High Island, Texas -- a fallout triggered by inclement weather overhead.
I'm haunted by images of the tiny colorful bodies of neotropical songbirds littering the sidewalks of downtown Cleveland in mid-May after suffering fatal collisions with buildings the night before.
I've seen radar images that depict bright red blobs -- multitudes of songbirds -- passing over Lake Erie en route to their nesting grounds in the northern forests.
I'd hate to think what would happen if one of those bird clouds dropped into the perilous whirl of a windmill.
"Will some birds be killed? Certainly, it's totally unavoidable," said Ralf Krueger, CEO of JW Great Lakes Wind LLC, one of the authors of the feasibility study. But the tradeoff is worth it when you consider the benefits of green energy, he said.
Tentative plans call for three to 10 windmills to be erected about five miles from the shoreline, two miles apart. To become economically feasible, there would have to be up to 100 or more windmills in the lake some day. Although strings of giant windmills can pose hazardous obstacles to birds, their killing capabilities can be mitigated -- when handled wisely.
To me, that means keeping your finger on the switch and turning off the windmills whenever radar depicts images of migrating birds or the onset of nasty weather.
In a report by Geo-Marine Inc., engineers measured fives years of data collected from radar images and bird studies of abundance, status and distribution. Two primary sources were Larry Rosche's "Birds of the Cleveland Region," and Bruce Peterjohn's "The Birds of Ohio."
The researchers determined that, in the spring, inclement weather conditions that would force birds to fly lower occurred on 26 of 305 nights. In the fall, the instances of bad weather were less frequent, occurring on 28 of 465 nights, the study found.
How difficult would it be to switch off the windmills for a few hours on those nights when tens of millions of songbirds are passing over Lake Erie in May and September?
Possible, but not recommended, Krueger said.
"If one could make a case that a severe massacre might happen it might be realistic to do that," Krueger said. "But a weather pattern such as that would apply only one or two nights. If you're talking 60 or 90 nights the economics would go all to hell."
The impact of windmills on water birds such as gulls, ducks, loons, shorebirds and pelagic species likely would be insignificant. Those species usually avoid wind farms, the study found. Most hawks avoid crossing the lake altogether, and usually fly at high altitudes over land.
It is unlikely that the project will pose a significant barrier to bird migration or local flight paths on Lake Erie, the study concludes.
For the sake of birds and birders, we hope the research is accurate.