ALBANY, N.Y. -- While generating megawatts of electricity, windmills on the Tug Hill Plateau in northern New York are also killing hundreds of bats and birds, according to a recent study.

The consultants' report for PPM Energy and Horizon Energy identified 123 birds, mostly night migrants, and 326 bats found dead over the course of five months last year beneath 50 wind turbines on the plateau between Lake Ontario and the western Adirondacks.

The initial results from the ongoing study at the largest wind farm in New York state, which is required to assess its environmental impact, were also distributed to state and federal wildlife and energy officials.

"We already have a reasonably good idea of how birds are migrating across New York state, which is why we are reasonably confident the bird mortality on Maple Ridge will not prove significant," said William Moore, project developer for PPM Energy. "The story on the bat side is a little more complicated."

The Adirondack Council repeated concerns that wind turbine parks have been proposed in a virtual ring around the 6-million-acre Adirondack Park, saying the threat to migratory birds needs to be better studied before towers are built.

"It's hard to justify this kind of bird and bat slaughter for the amount of electricity we're generating here," council spokesman John Sheehan said. "Ultimately we think there are good places to put windmills and wind turbines, but we need to do some study before we start putting them up, and that wasn't done here."

Moore said the 195 wind turbines, spread across 12.5 miles, have all been operating since late 2006 and are generating about 900,000 megawatt hours annually, or about 2 percent of the residential electricity load in the state. The first 120 turbines have been running since 2005. While the prevailing wind comes from the southwest, the turbines can yaw into the wind to receive energy from any direction, he said.

The plateau is one of the windiest places in New York, PPM is considering a second turbine site in Lewis County, and the final report on the 2006 bird and bat data should be issued in a few days, Moore said.

A National Research Council panel reported to Congress this month that wind farms could generate up to 7 percent of U.S. electricity in 15 years _ helping reduce air pollution from burning coal and oil _ but too little is yet known about the risk to birds and bats.

At the Maple Ridge Wind Power Project, the wind turbines have 262-foot towers, three 134-foot blades that turn between 12 and 20 rpm (more than 130 mph at their tips), and a generator in the base, according to the company. They have a maximum height of 400 feet, are painted white and each can produce up to 1.65 megawatts of electricity. On an annual basis, they operate at about 30 percent of capacity.

The report data don't include spring migration, expected to increase the annual bird death rate slightly. About two-thirds of the dead birds found from July through November were songbirds, and 82 percent were night migrants, the report said.

Almost one-third of the windmills have flashing red aviation warning beacons. The study, prepared by consultants Curry & Kerlinger, said there was no clear evidence the lights attracted birds and bats. The report said the turbines are less deadly to wildlife than taller communications towers, and flashing beacons are less attractive than steady burning lights.

The Adirondack Council advocated radar tests to count the actual number of birds and bats in the area, both night and day and year-round, and to determine whether any pass the turbines unharmed.

"We're very much in favor of home size and farm scale wind production, and we think the risks especially from these lower towers are very minimal," Sheehan said. "Once you get up above 20 and 30 stories you can really have an impact on the environment and you've got to be careful where you put them."

According to Moore, preconstruction radar studies were done, and others are planned this year. None of the 28 species of birds found so far are on the endangered species list. Most of these "migrate on what is known as broad front," or in a fairly confused way, suggesting one turbine location is no better or worse than another, he said.

None of the five species of bats found dead is listed as endangered either, Moore said. "They're colliding with turbines for reasons nobody can explain."

Methods to repel bats will be tested, he said.