Research Evaluates Birds at the Ainsworth Wind Facility

By James Ed. Ducey

Recent research in the sandhills of Brown County, illustrates the features of birds and their response to wind turbines in a prairie landscape.

Cattle at the Ainsworth Wind Energy Facility. Courtesy of NPPD.

The Ainsworth Wind Energy Facility, and which is atop Ikenburg Hill, a historic local place-name, was surveyed in three ways last year to evaluate the resident species and the response of local species to the wind towers.

The first bird counts done at the site of the potential wind-power facility, had been carried out in 1996 and 1997, when a night-calling monitoring station was setup by a Cornell University researcher, said Rockford G. Plettner an environmental specialist with the Nebraska Public Power District (NPPD). It was monitored from the fall of 1996 – spring of 1997 to determine the species composition and abundance and height of the flight over the site by migratory birds. Results indicated there were not a large number of nocturnal migrants. The effort was funded by NPPD.

"We had discussed bird kills in association with wind turbines, at meetings with state and federal officials," said Rocky Plettner, environmental specialist with NPPD. "We wanted the facts to present, especially with more wind development to be occurring in Nebraska and the Midwest."

The Ainsworth facility went into operation in October 2005 and is owned and operated by NPPD.

A $60,000 research project evaluating how wind turbines impact birds was conducted by NPPD. It involved searches for bird and bat carcasses were done every 14 days using a standard method in a 200 foot square surrounding each of the 36 wind turbines on the site. The study period lasted from March 13 to November 4, covering spring, the summer breeding season, and autumn.

Common Name	Ikenburg Hill	Ainsworth Wind Energy Facility
Canada Goose		1
Wood Duck	2
Gadwall		1
American Wigeon		1
Mallard		1
Blue-winged Teal		2
Northern Pintail	1
Ring-necked Pheasant	1
Sharp-tailed Grouse		2
Greater Prairie-Chicken		1
Wild Turkey		1
Turkey Vulture	1
Swainson's Hawk	1
Red-tailed Hawk	2
American Kestrel	2	2
Upland Sandpiper	3	1
Mourning Dove	6
Burrowing Owl	2
Short-eared Owl		1
Western Kingbird	1
Eastern Kingbird	3	1
American Crow	1
Horned Lark	4	12
Barn Swallow	1
House Wren		1
American Robin		1
European Starling	1	2
Spotted Towhee		1
American Tree Sparrow		1
Vesper Sparrow		1
Lark Sparrow	3
Lark Bunting	1
Grasshopper Sparrow	2
Song Sparrow		1
Dark-eyed Junco		1
Blue Grosbeak	1
Dickcissel		1
Red-winged Blackbird	1
Western Meadowlark	7	2
Brown-headed Cowbird	5
Orchard Oriole	1

Biologists with the Nebraska Game and Parks Commission helped by evaluating the spring display grounds of prairie chickens and prairie grouse. Bird sightings by a local bird watcher also provide dates of occurrence for a different variety of species during the spring months.

The results from the company research were issued in February 2007 in a report titled: "Post-construction Monitoring Report for Avian and Bat Mortality at the NPPD Ainsworth Wind Farm."

Estimated annual total bird mortality would be 148 (calculated by taking annual rate of 4.10 per turbine per year multiplied by 36 turbines), according to Plettner. The annual rate differs from the period of study rates in that the assumption is made that the number of fatalities during the winter is similar to the rest of the year. NPPD’s estimate of 2.49 bird fatalities per megawatt per year is low in relation to other wind power facilities studied throughout the U.S. and comparable or low to those studies in the western and Midwestern portions of the country, he said.

As NPPD has been looking at adding wind generated power, questions have been asked by a small number of landowners about the potential for bird kills at wind power facilities, said Mark Becker, company spokesperson with NPPD. The company study gives a comprehensive look at the answers, at least from what has been experienced at Ainsworth.

Among the 14 species documented during the mortality investigation, the most common represented were local residents such as the Horned Lark, Western Meadowlark, American Kestrel.

Overall, combining all three of the survey efforts, at least 41 species were noted among the site habitats. Most of them were observed during field studies, not found during the mortality study. The value shown in the table is the number of times observed.

Even though the Mourning Dove was present on nearly every bird survey at the hill, they were never noted to have struck a tower turbine. Neither was the Brown-headed Cowbird recorded in this manner.

The Greater Prairie-Chicken and Sharp-tailed Grouse continue to use the prairie grasslands about the towers. There were eight leks within the facility, with five others just adjacent on private property, according to the Nebraska Game and Parks Commission report provided to NPPD. Both species were also noted as nesting in early May by a wildlife research scientist from Wisconsin.

The populations of the chicken and grouse were similar to the number of expected birds elsewhere in Brown and Rock counties, the report concluded.

A number of additional species are known for the region with a few miles of the wind farm. Prominent locales where bird surveys were done during 2006. The list has more than 110 species when including the marshes and wet meadows of nearby Paradise Valley, Yellowthroat WMA and Hitchcock Bayou. Waterfowl and waterbirds are well represented.

Birds such as migrant Whooping Cranes, an endangered species, as well as any other threatened or endangered animal or plant species were discussed in consultations with the Fish and Wildlife Service and Nebraska Game and Parks Commission, said Plettner. John Richards, an engineer with the company’s renewable energy development program explained that NPPD must comply with FAA guidelines for placing lights at 24 turbines, FCC and county planning zoning requirements to the list.

Facilities at the Ainsworth wind farm comprise about 50 acres of an 8,300 leased acres of sandhills upland prairie. Much of the grassland area is grazed by cattle during the growing season.

NPPD prefers to "site towers at locale that do not impact native habitats," Plettner said, avoiding wetlands such as those in the Rainwater Basin, and away from refuges.

NPPD plans to add 150 megawatts of wind-turbine generated power to its power mix by the end of 2008, Becker said. This will be done through private developers and Community-Based Energy Development (C-BED) programs that have been proposed to the company. NPPD is currently negotiating Power Purchase Agreements for the purchase of electricity from three potential proposals. At the same time, NPPD is studying potential sites for future wind farms throughout the state of Nebraska, which they can possibly construct or utilize a private developer or C-BED organization to construct and operate, he said.

Numerous private developers are currently also looking at possible future locations for wind farms. A sandhill site being evaluated is in northeast Holt County, as well as northeast Nebraska.

A top priority of the power district is to have wind power sites in close vicinity to existing  power transmission lines and studying those lines to determine if additional load can be added. This reduces the cost of project development, and also reduces any associated development that can impact native habitats.

"The Ainsworth study gives us more knowledge about the issue that can be applied to any future wind farm projects," Becker said. "At the same time NPPD continually works towards the protection of migratory birds in all its operations while balancing its mission of providing reliable cost-effective electrical service."