Can We Have Wind Power and Birds, Too?

By Hugh Powell
August 14, 2008
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The answer emerging from recent research seems to be a hearty ‘yes,’ qualified by a ‘but let’s not rush into things.’ This was the sentiment offered by Ken Otter, of the University of Northern British Columbia, as he described a two-year study of bird migrations at a proposed $500 milion, 170 megawatt wind-power plant.

Wind power has emerged as a front runner in the world’s sudden longing for renewable energy sources. It’s clean, abundant, fairly straightforward to produce, and even pretty quiet compared with an oil derrick or coal plant. There’s just the small problem that the monstrous structures – the one at left is taller than a football field stood on end – present a sometimes-deadly obstacle to passing birds and bats.

Still, to the pragmatic, having wind power boils down to accepting a certain amount of dead birds. And you can put a number on the amount: At last week’s AOU meeting, I learned that existing wind-power plants typically kill about 1 to 12 birds per megawatt generated per year. (A megawatt can meet the electricity needs of roughly 1,000 Americans.)

Ken Otter’s task was to advise the Canadian power company about ways to get that number as low as possible. So he hauled out a mobile radar system to track birds as they flew over the steep-sided mountain ridges where the turbines would be built. Radars can’t identify bird species, so Otter also posted graduate students with binoculars to document what was flying over.

The challenge for wind farms is that migrating birds don’t fly randomly across the landscape – they follow the wind, too, and many fly at night, making it hard to see the rotating blades.

Raptors are especially vulnerable: they soar low along ridgelines, where they catch updrafts from wind deflected up the mountainsides – exactly what the wind turbines are there to do. And even though raptors migrate during daylight hours, Otter said, they don’t always do a great job of looking in front of them. The solution just isn’t as simple as putting wind turbines in places birds don’t travel, it seems.

But after two years of study, Otter found bird movements tended to be fairly predictable. Songbirds tended to fly safely above the height the turbine blades will be when they’re built later this year. Raptors tended to cross the ridge in a predictable zone, and they tended to come through in tight groups over just a few hours or days. By monitoring weather conditions, he said, he can warn the power company that raptors are probably on their way, allowing operators to shut down turbines long enough for the birds to pass by, without making the outage too costly.

This is why preparatory studies are valuable. Even though wind power is a green energy source that we’re right to feel enthusiastic about, it does have a cost that can be minimized. Different settings – shapes of ridgelines, prevailing wind patterns, migratory routes – mean that each new wind farm will present different hazards to birds. But with a little forethought and brain power, we can reduce the costs birds pay to satisfy our own energy demands.

Wind power will never be harmless to birds. After all, radio towers kill birds, and they’re just a latticework of metal bars that’s completely motionless. But climate change and pollution kill birds, too; it’s just harder to measure (or fix). As Otter said at the end of his talk, “I’d like to see these turbines go in, because the alternative is they’re going to build coal plants.”


  • Laura Erickson

    It’s so hard to predict the future, but after researching 101 Ways to Help Birds, which was published two years ago, I came up with the same conclusion. We do need to keep funding research into minimizing the kill, but all the while remembering how many birds are killed or reproduction harmed by the toxins emitted by burning coal (the biggest source of environmental mercury), how much habitat is lost to mountaintop mining, and how much damage is being done by acid rain caused in large part by burning coal–Wood Thrushes in some areas are starting to show eggshell thinning because the calcium in the soil is getting depleted by acid precipitation, leaving less calcium for invertebrates which thrushes eat.

    Meanwhile, the best take-home advice for everyone is to conserve energy.

  • lclc

    We need to add to Laura’s list the staggering number of birds killed every migration season by radio and TV antennas and cellphone towers. It’s way past time that these structures receive the same scrutiny that wind farms do.

    The Veteran Naturalist

  • Or, put the turbine offshore where the winds are stronger and more reliable, the land is permitted and not purchased and there are far fewer migrating songbirds and no raptors. The one (and only one, unfortunately) study on offshore turbines found that each turbine killed one bird (overwintering common eiders, in that case) or less per year.

  • Laura Erickson

    The Veteran Naturalist is right. It’s actually very inexpensive to reduce daytime collisions with powerlines if “bird flight diverters” are put in place when lines are constructed, but power companies usually choose to wait until a documented large-scale kill takes place (and these are hard to document) before retrofitting, at much greater expense. Electrocution and collisions at power lines and poles is the number one cause of mortality for Harris’s Hawks in the Tucson area. And communications tower collisions are a growing problem (and they were already a significant problem) because of the many taller towers being constructed to carry high definition TV signals.

    We’re creating so very many problems for birds that each one becomes a bit smaller in overall significance, not because it’s less unimportant but because so many additional assaults are happening. This overwhelms people and makes them feel helpless, leading to apathy, leading to nothing being done about any of the issues.

  • Martin Piorkowski

    These are great comments to a hotly debated issue. As the original post explained, the issue here is how to minimize environmental impact on what is often termed a “Green” energy. Is a wind facility better than a coal facility? I tend to believe the answer is yes; however, that is not everyone’s feeling.

    Although I agree that there are other sources of anthropogenic disturbances that kill birds at rates that are magnitudes higher that what we have seen with wind power, but wind power does contribute to the overall number. Is that acceptable? Laura makes a good point to say that this is another each new disturbance reduces the overall significance, but does this make any of the less importance? Let me put this another way. Should we be any less responsible for any of the effects cause by wind power?

    As far as offshore wind power, here’s the biggest controversy yet. Finding turbine cause fatalities is incredibly difficult in the best of conditions, and nearly impossible under the worst conditions (as least using conventional survey methods) The Wind Power companies have acknowledged that this is a difficult thing to quantify as does consulting firms and scientists alike. Offshore wind farms also product a whole suite of new questions related to palagic birds, and marine animals (whales, fish, seals, and other oceanic organisms). Will offshore facilities cause a change in these animals’ movement patterns? What effect will that have on the species? It is already documented in Europe that sea ducks avoid feeding near offshore areas with turbines present even though there is an ample food supply.

    I think the most accepted comment right now concerning wind power and environmental impacts, is that more research needs to be done. General baseline research is paramont, but we also need to continue refining current questions and defining new ones to help us move forward in our understanding. Simply documenting dead birds at the bases of turbines will not be enough if we are going to help minimize the environmental footprint of these structures.

  • Kathy Griffith

    We are anxiously waiting the result of a newly published bird study which supposedly supplants bird studies done by friends of our for the wind farm owned by PPM (company has changed name)in KLeberg County. We also belong to Coastal Habitat Alliance on the TX central coast which advocates and is supporting federal and state regulations for wind farms none of which exist at the present time.

  • Wind turbines have blades, similar to jet liners. Birds have been a problem at many airports and a real danger to pilots and passengers. Wind farms really have not posed a danger to humans that I know of. Are we more concerned about the birds, or people?
    Maybe there is a way to see what steps airports have taken to protect birds and relate, however loosely, to wind turbines. Just an idea.