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 pose a serious problem. Indeed, many people argue that such a number 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. This call for action by well-meaning people represents an extreme and irrational response based on little or no understanding of the problem.
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. The paper gives us the best currently available data comparing the specific causes of bird death, and I have drawn on the 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, 6,000; domestic cats, 4,000; striking private homes, 1,200; vehicle collisions, 750; the game bird harvest, 200; pesticides, 150; transmission tower kills, 101; striking commercial buildings, 90; transmission line collisions, 65.
Almost three-quarters of all of these human-related deaths are caused by cats: 43 percent by feral cats, 29 percent 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, which support cellphones and radio and television stations. They kill 100 times as many birds as do wind turbines, yet turbines are far more strictly regulated. Although tower kills represent a very small fraction of the hazards we erect for birds, research is suggesting ways to reduce those 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.
Also, most bird migration takes place at night, when they are easily confused by lights. The results of one study suggest that avian fatalities can be reduced by more than 50 percent by removing non-flashing/steady-burning red lights. 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.
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.