A new study by a leading conservation organization warns that construction of wind farms could pose a high risk to wildlife habitat on 8 million acres of land in Montana.

"Wind farms have pretty big footprints, and we want to encourage wind developers to put those wind farms in places with the least amount of impact," said Brian Martin, director of science for the Montana Nature Conservancy, the report's author.

"Ecological Risk Assessment of Wind Energy Development in Montana" is the first analysis of where the best winds and wildlife intersect in Big Sky Country and is meant to help developers minimize risk to birds and animals and guide policymakers, he said.

The report's release comes as wind development is picking up in the state and the Legislature considers bills encouraging more development on state land and better siting on private property.

Last year, 126 megawatts worth of wind power were constructed, bringing the state's total to 271.

The study says the state has 17 million acres of public and private land with high potential for wind development.

But wind farm development would be a "high risk" to wildlife on 7.7 million acres that provide "critical habitat" for 30 species, the report says.

Instead, the report encourages development on 9 million acres that has high wind potential but is already developed, primarily with crops.

"Very few species use cropland," Martin said.

Wind farms can fragment wildlife habitat because they have a large network of roads and transmission lines, the study says.

Construction would pose a high risk to wildlife in some locations in central and eastern Montana, where sage grouse populations are located, and the Rocky Mountain Front west of Great Falls, home to grizzly bears, the study says.

Both sage grouse and grizzly bears avoid roads, the study says.

Additional study of the impacts of the tall poles and spinning blades on birds and bats is recommended.

"There's not a lot of information for a lot of these species because wind is just developing," Martin said.

To find out where the best wind and wildlife habitat meet in Montana, the Nature Conservancy placed maps of wildlife habitat over maps of the state's best wind.

The Montana Natural Heritage Program, a part of the University of Montana, also did inventory work on birds and bats as part of the study, which Martin said was prompted by the state's lack of wind regulations.

The risk of wind farms to wildlife in much of the Golden Triangle is low, Martin said.

"I think it's a good idea for us to be proactive on wind siting," said Janet Ellis, program director for Montana Audubon, a bird conservation organization.

Audubon is backing House Bill 584, which the Montana House approved 81-18 Wednesday.

It would set up a voluntary certification program in which wind developers could receive state certification by siting projects away from areas that attract wildlife, such as streams and migration routes.

A committee would be formed to study the details, including incentives for developers to participate and certification criteria. Legislation would be introduced at the 2011 Montana Legislature.

Ellis says 11 states have voluntary guidelines regulating wind development, while four have mandatory siting processes.

The House also OK'd a bill Wednesday limiting environmental rules to encourage wind development on state school trust land.

Some developers are using both state and private land for wind farms. Under state law, an environmental review is required for the entire wind farm if any portion of the overall project involves state school trust land.

House Bill 529 would eliminate the review on the privately sited portions of a wind farm if state land makes up less than 33 percent of the overall project.

Rep. Llew Jones, R-Conrad, said the change would encourage developers to use more state land for wind projects. He introduced the bill because developers are building projects around school trust land on private land to avoid the environmental review.

"It's great the local landowners make some money, but we also want to have our state lands have the opportunity to generate money for the schools," Jones said.

Revenue the state gets from wind development on school trust lands goes to public schools.

Montana Audubon opposes the bill. If the change is made, Ellis said most of the acreage involved would escape environmental review because developers won't use more than 33 percent of state land in a project.

"There's no wind farm in Montana that's met that threshold," she said.