Wind Turbine Bird Kills
Wow! Did you realize that as many as 50,000 birds are killed each year by wind turbine collisions across North America?
As I have presented that information, wind turbines seem to represent a serious problem. Indeed, many people argue that such a total calls for a moratorium on wind power. One individual, upset by the location of a wind farm on Ontario's Amherst Island near a woodland where owls winter, has even called for a boycott of Canadian products and travel to that country.
I reject those calls for action and consider the latter an insane indictment of our Canadian friends. It represents an extreme and irrational response based on little or no understanding of the identified problem. Unfortunately, however, it also represents a kind of thinking widespread among well-meaning people.
In this column I seek to place in perspective the numbers on which that kind of thinking is partly based.
As it happens, a seminal paper by a group of Canadians headed by Anna Calvert of Environment Canada has recently summarized a series of controlled research studies of human-related causes of bird deaths in that country. Their paper gives us the best currently available data comparing the specific causes of bird death and I have drawn on their report published in the journal Avian Conservation and Ecology for the following comparisons. That 50,000, however, represents the total of bird deaths for all of North America. In it I have included the U.S. Fish and Wildlife estimate for this country.
Fifty thousand birds killed seems like a great many until you consider the total number of bird deaths each year. It turns out that only one out of 14,000 is due to those turbines. It should be clear that the general effect of wind turbines on our bird populations is infinitesimal.
Well, just what is killing those birds? For every one windmill death the following approximate numbers are killed by other means: feral cats, 6000; domestic cats, 4000; striking private homes, 1200; vehicle collisions, 750; the game bird harvest, 200; pesticides, 150; transmission tower kills, 101; striking commercial buildings, 90; transmission line collisions, 65.
It is worth considering a few of those numbers more closely.
Almost 3/4 of all of these human-related deaths are caused by cats: 43% by feral cats, 29% by domestic cats. Another way to think about those numbers is to compare them with the effect of hunting. For every game bird shot, 19 birds are killed by domestic cats, 28 by feral cats. Can you understand then why I strongly support the Cats Indoors program of the American Bird Conservancy and equally strongly oppose the Trap-Neuter-Return program that supports thousands of cats that are killing birds and small mammals?
And think too about transmission towers, those towers that support your cell phone as well as radio and television stations. They kill over 100 times as many birds as do wind turbines yet turbines are far more strictly regulated.
Okay, tower kills represent a very small fraction of the hazards we erect for birds. But research is suggesting ways to reduce those deaths as well.
Tower height and the use of guy wires to support the structure have an effect on bird deaths. A Michigan study found that guy wires increased the number of fatalities by a factor of 16, and that tower height quadrupled that factor. By constructing only un-guyed towers of medium height, many bird lives would be saved.
Most bird migration takes place at night, the birds foraging during the day to stoke up the energy needed to continue. And at night they are easily confused by lights. The results of one study suggests that avian fatalities can be reduced by over 50% by removing non-flashing/steady-burning red lights.
Here is where you may be able to help. If you observe such a structure lighted at night with steady lights, communicate the need for the simple but effective change to flashing lights to local authorities.
This has been a column burdened with mortality statistics. But Shakespeare reminds us that there's a special providence in the fall of a sparrow. We cannot undo civilization but we can do our best to minimize the devastation we cause.-- Gerry Rising