GREENBELT, Md. - A proposed West Virginia wind power project will harm a tiny, endangered bat and its developers should be should be required to obtain permits under the Endangered Species Act, attorneys for two environmental groups argued Wednesday in federal court.

The developers admit bats will be killed by the turbines, but refuse to acknowledge the endangered Indiana bat will be among them, plaintiffs attorney Eric Glitzenstein argued in his opening statements.

"Is there some reason to think Indiana bats will escape the fate" of the other bats expected to be killed, Glitzenstein asked District Judge Roger Titus, who is hearing the bench trial.

Defense attorney Clifford Zatz said the $300 million, environmentally responsible, renewable energy project is in "limbo" because of an untested hypothesis "over a rare bat that no one has ever seen at the site."

The Washington-based Animal Welfare Institute and the Williamsburg, W.Va.-based Mountain Communities for Responsible Energy sued Rockville-based Beech Ridge Energy and Invenergy Wind. The groups say the defendants should be required to obtain U.S. Fish and Wildlife Service permits for the Greenbrier County, W.Va., wind farm.

The first day of the expected three-day trial in U.S. District Court dealt with testimony by experts over whether the quarter-ounce Indiana bat with a six-inch wingspan can be found at the site.

Penn State University bat researcher Michael Gannon said surveys using nets at the site have not captured an Indiana bat, but recordings indicate the endangered bat is at the site. The judge questioned the researcher himself after the opposing attorneys did.

Gannon told the judge that of the 160 recordings that he reviewed, he was able to make an identification of 42, including three he thought were the endangered Indiana bat, although he could not say whether the recordings were of three separate bats or the same bat on three occasions.

Under questioning by Glitzenstein, Gannon said he thought bats were at the site based on the location, habitat and recordings and he felt it was likely they would be harmed by the project. Under cross-examination by Zatz, who questioned the accuracy of audio recordings, Gannon acknowledged Indiana bats had not been captured during netting survey, but added that the netting efforts were not intense enough.

In his opening statements, Zatz said the burden of proof rested with the plaintiffs and a better solution was what he called "adaptive management" of the project if it is found to affect the Indiana bat.