Do wind turbines pose a threat to birds?

As the U.S. becomes increasingly reliant on foreign oil, approaching crisis levels, any alternative energy source is becoming more appealing. With environmental destruction from coal and gas-derived power reaching alarming levels, even solutions still years away seem promising. Wind power, a sustainable energy option that is far cheaper than nuclear and coal energy while producing minimal environmental pollutants, appears almost perfect to many of us.

However, there are those who disagree and are opposing the expansion of wind turbines in the United States. They argue that bird deaths are an unacceptable consequence of wind energy. Through legal action and protests against pending legislation, they aim to prevent large numbers of birds from being killed by the turbines' blades.

Most experts, however, point out an issue with the bird-death argument: A significant amount of research indicates that wind turbines cause relatively few bird deaths, especially when compared to other man-made structures. The statistics are startling when considering how many people are rallying against wind power for the sake of birds:

Collisions with wind turbines account for only about one-tenth of a percent of all "unnatural" bird deaths in the U.S. annually. Additionally, 30 percent of bird deaths are due to natural causes, such as young birds falling from nests [source: AWEA]. So why is there such a widespread belief that wind turbines are "bird-killers"? It all traces back to California, raptors, and the thousands of old turbines at the Altamont Pass wind farm.

In this article, we’ll explore where the statistics went wrong, how thousands of birds do end up colliding with wind turbines each year, and what is being done to reduce these bird-turbine crashes.

Challenges Posed by Wind Turbines

The risk that wind turbines pose to birds is obvious: Enormous blades, spinning at speeds of up to 179 mph (80 meters per second), and positioned hundreds of feet (at least 30 meters) above ground, present a clear danger to anything flying nearby [source: MIT]. Unfortunately, birds do collide with the spinning blades, leading to often deadly outcomes. Most of the affected birds are songbirds, with around 10 percent being birds of prey such as raptors [source: ABC]. These raptors have been the primary focus of protests after numerous dead birds were discovered scattered across the Altamont Pass wind farm in Northern California.

Bird conservationists became deeply concerned, and the idea that wind turbines could pose a significant danger to bird populations gained traction from there. By applying the mortality rates from Altamont Pass to all wind farms across the United States, the estimates of bird deaths became severely overstated. In reality, Altamont Pass stands as a distinct example of a wind farm that truly represents a serious threat to birds.

Altamont Pass stands apart due to two primary factors: the placement of the turbines and their design.

The Altamont Pass energy farm in California houses over 4,000 wind turbines. As one of the earliest wind farms in the United States, its turbines are now over 20 years old. Their outdated design has since been abandoned: the latticework blades, with their minimal surface area, are not only inefficient for energy production but also dangerous to birds. The lattice structure itself attracts large birds, as the frame serves as an ideal perch. Raptors, in particular, are drawn to the blades, leading to high collision rates.

Another design flaw is the blades' small surface area, which forces the blades to spin faster in order to generate electricity. The faster the blades rotate, the more perilous they become for nearby birds. A bird flying near these high-speed blades is unlikely to survive the encounter.

To make matters worse, the Altamont Pass power plant is situated right in the middle of a crucial migratory route for large birds. This area also hosts the world's largest population of golden eagles [source: USA Today].

Estimates for the total number of bird deaths across all wind farms in the United States range from 140,000 to 328,000 annually, according to a 2013 estimate [source: Loss, et al.]. While up to 1 billion birds die each year from colliding with windows, the fatalities caused by turbines, though significant, are not being ignored. What steps are being taken to reduce this number? On the next page, we'll explore the measures being introduced to protect the birds.

Location, Location, and Surface Area

Over the past few decades, turbine designs have undergone significant changes. Today, turbine blades are solid, eliminating the lattice structure that once attracted birds seeking a place to perch. Additionally, the surface area of the blades is much larger, meaning they don't need to spin as quickly to generate power. Slower-moving blades reduce the risk of bird collisions.

One of the most important advancements in wind farm safety involves the location of turbines. New turbine proposals are now carefully assessed to ensure they are placed in bird-friendly areas. Wind farms cannot be constructed along migratory paths, in regions with large bird populations, or in areas with features that could eventually attract significant bird numbers. The rising trend of constructing offshore wind farms is also beneficial for bird safety, as offshore farms typically experience fewer bird collisions than those on land.

A key sign that wind turbines are not the massive bird killers they are often portrayed as is the growing number of endorsements from bird conservation organizations. The American Bird Conservancy supports wind power, provided that bird-friendly placement and design are prioritized during construction [source: ABC]. The Wisconsin Bird Initiative claims that wind turbines have a "low impact" on avian mortality compared to hazards like window glass and communication towers [source: WBCI]. In 2006, the Audubon Society gave its endorsement to the American Wind Energy Association. The president of the national organization was quoted by Renewable Energy World saying, "When you look at a wind turbine, you can find the bird carcasses and count them. With a coal-fired power plant, you can't count the carcasses, but it's going to kill a lot more birds" [source: REW].

Naturally, the ideal situation would be no turbine-related bird deaths at all, but such a goal seems unrealistic given the need for energy production. The most achievable outcome is smarter turbine placement and improved bird-friendly designs, which would continue to reduce bird deaths caused by one of the best alternative energy sources available today. For instance, Altamont Pass is gradually replacing its older turbines with newer models to address this issue.