Montana Audubon

Montana Audubon works at the local, state and national policy levels to protect our natural heritage.

Wind Energy

Wind power is an important part of a clean and sustainable energy economy. However, proper siting of wind turbines and infrastructure is important to avoid damaging habitat and wildlife resources.

Montana Audubon works to ensure that wind energy producers do not locate their facilities in critical habitat for birds or other wildlife. Collisions with turbines can kill many birds outright, and wind turbines are known to negatively affect local bat populations. Construction and use of roads and building transmission lines will often displace birds and other creatures from a wide swath of habitat.

To guide us in our work, Montana Audubon has adopted a Wind Energy Siting Policy Guidance Document.

More Wind Power Development Coming to Montana:

Montana ranks #1 for class 3 or better wind and major projects are currently planned for development throughout the state. Since they do not require permits in Montana, it is difficult to track where projects are being built. However, based on several sources, we have created the following map  of developed and proposed commercial wind projects:


To download this map as a pdf, click HERE.

Impacts to Montana Wildlife:

Commercial wind development harms bird populations by increasing mortality due to outright collisions with turbines, and overall fragmentation of habitat.

Bird Collisions with Wind Turbines:

Since most birds migrate at night, they are vulnerable to collisions with structures such as wind turbines. This is especially true when weather conditions force birds to fly at lower elevations.

In Montana, studies at Judith Gap Wind Farm indicate that there are fatalities between 3.3 – 4.5 birds per turbine per year. Environmental studies done prior to construction of this facility predicted this fatality rate, which is considered acceptable for a wind project because it will not impact bird populations.

The positives about newer wind turbines is that they do not have places for birds to perch or nest: these turbines lack lattice structures where birds could perch. In addition, transmission lines between turbines are nearly always buried underground. Fewer birds using turbines, power lines and poles, means a reduced potential for birds striking turbines. This is especially true on the prairie, where perches are particularly attractive to everything from meadowlarks to raptors. Since this design change, the number of birds killed by wind turbines has decreased significantly.

Bats and Wind Turbines:

There are at least two ways that bats are killed by wind turbines. First, since most bats migrate at night, they are vulnerable to colliding with structures such as wind turbine. Bats may be attracted to the moving blade of the wind turbine. This attraction can spell trouble: if bats get too close to the turbine blade, they can be sucked into the lower pressure area following the blade.

Studies at Judith Gap Wind Farm indicate that there are fatalities between 7 – 13 bats per turbine per year. Environmental studies conducted prior to construction of this wind farm predicted 4 bats per turbine per year. Consequently, the bat mortality rates were higher than expected. Newer studies about bats and turbines suggest that “barotrauma” is unlikely to cause mortality.

  • Migratory tree roosting bats were the most common bats killed by turbines at Judith Gap. Specifically, most of the bats found under turbines were hoary bats (Lasiurus cinereus) or silver-haired bats (Lasionycteris noctivagans), which is pictured above (photo by Kristi DuBois). These bats were killed during their August to September migration south.
  • In other states, Eastern Red Bat (Lasiurus borealis), which are also found in Montana, are commonly found to be vulnerable to wind turbine mortality.

Habitat Fragmentation:

Habitat fragmentation occurs when wind farms—and their associated roads, power lines, and other structures—displace wildlife. The effects of habitat fragmentation go far beyond the immediate “footprint” of the wind farm, because some wildlife—particularly prairie species—will avoid areas with high towers. A solution is to keep these projects close to established roads, cropland, and other developed areas—and away from large blocks of crucial wildlife habitat.

Commercial wind facilities in Montana use between 20 acres (Two Dot) and 50,000 acres (Glacier Wind Farm near Shelby).

Wind Facility Regulation:

Currently Montana has virtually no ability to regulate wind farms. Consequently, wildlife concerns may only be addressed if a project is located on public land. When this happens, an environmental review must be conducted under either the Montana Environmental Policy Act (MEPA) for state land, or under the National Environmental Policy Act (NEPA) for federal land (forest service, BLM, etc.). These environmental reviews usually allow the public to comment on the proposed project.

Modern Wind Turbine Technology:

Modern wind turbines are getting more efficient than their predecessors—and bigger in size.

Wind turbines used at Montana wind farms produce about 1.5 Megawatts (MW) of energy. In general, these 1.5 MW turbines are:

  • Height of Tower: 250 – 300 feet;
  • Blade Length: 100 – 130 feet;
  • Total Height of Turbines: 390 – 400 feet;
  • Wind Speeds Used by Turbines: Wind turbines usually start spinning when the wind is stronger than 6 – 7 miles per hour (mph); they stop spinning when wind speeds are above ~ 50 mph.
  • Speed of Turbines: The tips of the blades can spin as fast as 230 mph.

The good news about these newer turbines is that they don’t have lattice areas for birds to perch and transmission lines between turbines is nearly always underground. These two design improvements have reduced the number of birds killed by turbines significantly.

Larger turbines are currently being used in other states.

Learn More about Wind Energy:

National Audubon Society and NRDC have created MAPS of restricted lands and sensitive wildlife areas in the western US, to help plan energy development projects by avoiding key areas. View sensitive areas in Montana – go to Google Earth Outreach

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