Wind turbines on the southern Texas Gulf Coast, and in Kenedy County in particular, could have a "catastrophic" impact on migrating and local birds, according to a new environmental review commissioned by the Coastal Habitat Alliance.

Wind farm developers, however, maintain that the proposed wind projects on Kenedy Ranch will have minimal effects on birds.

The alliance, a group of 11 organizations that oppose the construction of two wind farms on 20,000 acres of Kenedy Ranch, commissioned Colorado-based EDM International to study the two proposed sites and critique the wind-energy companies' own studies.

EDM used U.S. Fish and Wildlife Service guidelines in evaluating the sites and concluded their placement was problematic, the report says.

"In terms of potential harm to migratory and local birds and bats, the location of the proposed wind projects in South Texas is among the worst that can be found on any piece of private land in Texas and rivals the damage that could occur if a similar project were built on a wildlife refuge," the report states.

The alliance paid EDM to conduct the review.

U.S. Fish and Wildlife Service in 2003 developed a set of guidelines for choosing wind farm sites. The agency suggests that wind projects not be built in a migratory pathway, in areas with a high number of birds or in regions with many endangered species.

Environmentally sensitive areas like the Texas Gulf Coast should be treated with special care, said Lori Nielsen, project manager at EDM.

"I do think there are some areas of the U.S. that require additional scrutiny," Nielsen said.

EDM's report also questioned the methodology used in the wind developers' evaluation of the sites. Both companies - Portland, Ore.-based PPM Energy and Australia-based Babcock & Brown - have said they've conducted in-depth studies and determined that migrating birds mostly steer clear of the area.

Nielsen said the companies' studies aren't sufficiently thorough.

"None of the studies done so far would stand up to scientific review," she said.

PPM Energy's studies were conducted by "highly trained professionals" and university experts, countered company spokeswoman Jan Johnson.

Officials from U.S. Fish and Wildlife, Texas Parks and Wildlife Department and other agencies reviewed the study results and haven't expressed the same complaints as the Coastal Habitat Alliance, Johnson said.

"We stand behind our studies," she said.

Babcock & Brown also has conducted migratory bird assessments and found little risk of bird mortalities from the turbines, officials have said.

Coastal Habitat Alliance members, which include Frontera Audubon Society, King Ranch and the Lower Laguna Madre Foundation, say they want federal or state agencies to conduct a study of the project.

The alliance filed a lawsuit last month against state officials and the wind developers, saying they were violating the federal Coastal Zone Management Act by building wind farms without an environmental review.

The wind farms should be operational by late 2008, according to developers.