Researcher Todd Katzner and the U.S. Department of Energyare tailing the same slightly ruffled, strawberry blond: an Eastern Golden Eagle equipped with a tiny cell phone that winters in Connecticut and summers in Quebec. Wingspan, 7 feet; weight,14 pounds; appearance, magnificent.
The eagle’s flight path could alter the course of wind farm development on the East Coast.
Birds and wind turbines share an affinity for windy mountain ridgelines putting them on a potential collision course, said Katzner, one of a dozen researchers studying the Golden Eagle’s migratory habits and hangouts.
Golden Eagles, whose wing-span can reach seven feet, use the “lift” or updraft created by surface winds hitting sloped terrain – hillsides and mountains – to soar. Bald eagles and Goldens also ride columns of rising air, known as thermals, which allow them to glide at altitudes of more than 1,000 feet, well above a 300-foot to 500-foot-tall wind turbine.
But the same steep ridgelines that permit Golden Eagles and Bald Eagles to hitch a ride on the wind as they migrate north and south, are the same gusty high points preferred by wind farm developers, said Katzner, professor of wildlife and fisheries resources at West Virginia University in Morgantown, whose Golden Eagle tracking project is funded by several sources, including the DOE.
And Golden Eagles are more apt to be killed by wind turbines than other raptors because of their hunting methods, experts say. In California, wind farms in the Altamont Pass area east of Oakland kill an estimated 70 Goldens each year, said Katzner, citing a recent bird mortality study.
Nationwide, it’s estimated that thousands of birds, including eagles, falcons, hawks, owls, gulls, waterfowl and songbirds are killed by wind turbines.
Eastern Golden Eagles are “among the rarest species out there,” said Katzner. West of the Mississippi River their population is estimated at 20,000; east of the river, estimates vary from 1,500 to 3,000 Goldens.
For years, researchers have focused on the Goldens that wing their way through the mountains of Pennsylvania and West Virginia, part of the Northern Appalachian range, and the emerging wind energy industry that has grown up there in the last decade.
But the discovery last year of just one female Golden Eagle near Connecticut’s Housatonic River has them speculating that she may be one of many that prefer the Nutmeg state.
“I think there may be more of these birds wintering in Northwest Connecticut than anybody has ever realized,” Katzner said.
While not an endangered or threatened species Golden eagles are protected under the 1940 Bald and Golden Eagle Protection Act against harassment or killing. But in the West wind turbines are killing Golden Eagles at a higher rate than other raptors. Their particular hunting style puts them at a greater risk.
The faster a wind turbine’s blades rotate, the more electricity it generates. For a bird whose migratory path passes over a ridgeline dotted with wind turbines – attempting to avoid the spinning the blades “is like trying to cross a freeway,” said David Brandes, civil engineering professor at Lafayette College in Easton, Penn., who studies raptors.
Birds rarely, if ever, fly into trees, so why can’t they avoid wind turbines?
While birds can easily spot trees and other stationary objects, they can miss the sweep of a spinning rotor, turning at more than 100 miles, making them nearly invisible.
And just as some mammals are better at crossing roads and avoiding vehicles, some birds are better at avoiding wind turbines. It varies by species, migration patterns and flight altitudes.
Birds with a long narrow wing, such as falcons, that employ a “flapping flight” are less likely to collide with a turbine than broad-winged birds that conserve energy by soaring, Brandes said.
When a broad-winged bird uses the updraft generated by hills and mountains to hover, “they’re at the turbine’s height, [200 to 400 feet] putting them in the rotor’s sweep zone,” Brandes explained.
And Golden Eagles are more likely to collide with a turbine than other raptors because they hover while they hunt.
It’s a little like trying to drive and text at the same time.
“They’re so focused on hunting, holding still in the air and looking for mammals, they don’t see the turbine,” Brandes said. “Bald Eagles don’t use that style of hunting.”
Just One Bird
How can the discovery of just one Golden Eagle in Northwest Connecticut lead researchers to think there might be at least a hundred more of her kith and kin in the region?
According to Katzner, Goldens exhibit “stereotyped behavior.” If there’s one Golden in an area – one female wintering in Northwest Connecticut, there are likely others. “There’s not a lot of individual variation,” he said.
In short, it’s unlikely she’s alone or a loner.
The female Golden eagle that Katzner’s tracking, was found in February 2011 by a snowmobiler near the New York/Connecticut border. Injured, she had puncture wounds on her feet from an animal. The Golden was rehabilitated at Tufts Wildlife Clinic in North Grafton, Mass., and released a month later near Cornwall, but not before she was banded and outfitted with a solar-powered transmitter, designed by Katzner’s company, Cellular Tracking Technologies LLC.
The transmitter she wears, No. 3354, is really a tiny cell phone, weighing a little over 3 ounces that plots her GPS coordinates every 30 seconds. When she flies close to a cell phone tower, the data are automatically downloaded, said Katzner who is tracking about 25 Goldens with the device.
But a month after her release, she stopped “calling home.”
It wasn’t until last month that she flew close enough to a cell phone tower that the data – a year’s worth of information as to her whereabouts – was downloaded.
Other evidence that there may be a large population of Goldens wintering in Northwest Connecticut is the fact that there weren’t any sightings in that area of a Golden Eagle wearing a transmitter, Katzner said. That points to their remote habitat and elusive nature which could explain why they are rarely spotted by humans despite their golden crested heads, Katzner said.
From the data Katzner collected, it turns out that the eagle spent last summer in the northeastern regions of Quebec. Last October she headed south and returned to the northwestern Connecticut/New York border in December and then spent three months in the area, before once again heading north this spring toward her breeding grounds in Canada, he said.
That migration path said Katzner, “was completely unexpected. We have expected these birds to be short distance migrants. We were surprised she went such a long way north. Based on this bird’s behavior we think they’re may be more birds wintering in Connecticut, New York, this area.”
Katzner used the 6,000 points to plot a detailed map of her journey, an invaluable document that he says can be used to advise the wind energy industry on where to build wind turbines that are eagle-friendly.
Katzner’s studies of Golden Eagles have also helped inform the U.S. Fish and Wildlife Service, which incorporated data he collected into the agency’s new land-based wind energy guidelines, released last week.
The guidelines are intended to assist wind developers in identifying bats and local bird species, including Golden Eagles, that may be affected by a wind project.
While the guidelines are voluntary, evidence of eagle kills would draw the attention of the U.S. Fish and Wildlife Service, who would then notify local authorities to launch an investigation.
In Connecticut, the Department of Fish and Wildlife or the Department of Energy and Environmental Protection would be alerted.
“We are looking at Golden Eagles as an indicator species,” Brandes said. “There are plenty of birds that migrate through Connecticut, bald eagles, red-tailed hawks, broad-tailed hawks. They fly in similar ways, following the mountains down through New England and would be at potential risk of wind farms.”
What is their risk in Connecticut? It’s not clear. Not a single commercial-size wind turbine has been erected.
Although the Connecticut Siting Council last year approved construction of a six-turbine, 9.6 megawatt commercial wind farm project in Colebrook, the West Hartford wind developer BNE Energy Inc. has only begun road clearing. BNE is waiting for a decision in a Superior Court appeal challenging the council’s authority to approve wind farm projects.
In seeking the council’s approval, the West Hartford developer, BNE conducted the required bird and wildlife impact studies. But the true impact, if any, on birds and raptors, including the Goldens, may not be known until the turbines start spinning. What is clear, however is that the state’s windswept ridges have been identified as prime wind farm sites.
Pennsylvania has about 15 wind farm developments and more planned. But what do those wind farms, located hundreds of miles away in the Alleghany Mountains and Poconos have do with Connecticut?
Several companies that Connecticut Light & Power buys power from happen to own, operate or buy power from wind farms in Pennsylvania. To meet Connecticut’s renewable energy standards, each company is required to deliver 16 percent of their supply from renewable energy, which includes solar, biomass or wind, said Mitch Gross, CL&P spokesman.
The number of Pennsylvania wind farms keeps growing. But rather than wait for the bird strikes to mount, the Pennsylvania Game Commission, responsible for monitoring bird and bat kills, has put a voluntary wind agreement program in place, said Jerry Feaser, an agency spokesman.
Under the program, wind developers can sign the agency’s voluntary agreement. The developers and the agency then work cooperatively to reduce the impact on birds and wildlife. That’s where information gathered by Katzner and other researchers plays an important role in identifying where bird strikes are likely to occur.
So far 33 companies have signed the agreement, Feaser said.
“We work together to avoid areas that would clearly pose a problem to birds and wildlife,” Feaser said.
There are simple fixes, such as moving wind turbines away from known bird migration routes, Brandes said.
“Moving these turbines back is going to reduce their speed somewhat, but compromises have to be made,” Brandes said.
“The future of…our national security, our environmental quality all depend on decreasing our reliance on foreign oil and on fossil fuels,” Katzner said. “Wind power is among the most important alternative energy sources currently available, and the mid-Atlantic region is a primary focus for wind power development.”
Global warming caused by the burning of fossil fuels pose a far greater danger to birds and wildlife in the long run than wind turbines, he added.
The goal of Katzner and other researchers is to create a region-wide map showing the relative risks posed by wind power to eagles and similar birds.
“These maps will allow us to make specific recommendations regarding siting of new wind farms and operation of existing wind farms, to mitigate their impact…on eagles and other raptors,” Katzner said.
Applying a little bit of social pressure on wind farm developers can also lessen bird strikes, Feaser added.
“If you want to be identified as supplying green energy, you can’t be green if you’re out there killing birds.”
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