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Concentration of CO2 in the Atmosphere

Bird Mortality and Wind Turbines

Staff article

A new study has been released called,A Synthesis of Human-related Avian Mortality in Canada. All but one of its seven authors are from wildlife divisions of Environment Canada, a department of the federal government. The study can be found at:

It has some notable information. The report says over 272 million birds are killed by human-related events in Canada each year.

Cranes flying north past wind turbines in the background. Photo by Erell.

Cranes flying north past wind turbines in the background. Photo by Erell.

It turns out that the most dangerous human-related threats to birds are housecats and their feral relatives. They are considered human-related because they are not native to North America, but were brought here by European settlers. In fact, they are considered important as an invasive species, and if they are allowed to breed and run wild, they can be very destructive. Feral cats account for over 42% of all human-related bird deaths in Canada, and domestic cats account for over 29%, for a combined total of 71.85%, or about 196 million birds each year

The other important causes of human-related bird mortality are structures, vehicles, and direct human action. Power lines cause over 9% of human-related bird deaths. Collisions with houses cause over 8%, and road vehicles produce about 5%.

Lesser causes of human-related bird mortality include agricultural pesticides (0.99%), collisions with low and mid-rise buildings (0.88%), non-migratory bird hunting (0.88%), migratory bird hunting (0.84%), powerline electrocutions (0.18%), and water transportation (0.12%). Interestingly, communication tower collisions produce only 0.08% of human-related bird deaths, and collisions with tall buildings produce only 0.02%.

A couple more items are of interest. Gill fishing nets cause 0.0075% of human-related bird deaths. And, slightly less important, wind turbines cause 0.0061%.

Items not listed here include are the nestlings killed by haying, and the nests destroyed by commercial forestry, power line maintenance, and hydroelectric production. These are not listed because they confuse the issue with such questions as whether an egg should be counted as a bird. Apart from these, however, all causes of importance equal to or greater than wind turbines are listed.

Why, you might ask, do we hear so much about wind turbines killing birds, if they don’t even kill as many as gill fishing nets? Also, are the figures possibly biased in favor of wind?

To answer the second question first, we can doubt that the wildlife experts in Canada would misrepresent facts for the sake of people who might make money on running wind farms or selling wind turbines. They have no reason to do so.

As to the first question, we might answer that people who talk about wind-related bird deaths also talk about wind farms doing just about all of the following: destroying property values, raising taxes, making people sick with Wind Turbine Syndrome, failing to provide income for the investors, destroying aquifers, destroying natural habitats, and even failing to replace the energy required to make the wind turbines. Some of these arguments are hysterical, and some are pathetically silly, but all have been soundly refuted, over and over, by peer-reviewed studies, and none seems to have been supported by articles that follow strict scientific standards.

So why would windpower be under attack? It’s possibly because of the following. First, windpower represents a financial threat to die-hard fossil fuel corporations. Second, there are people who can make a lot of money benefiting the fossil fuel corporations by promoting hysteria. And third, there are people who become hysterical, to the point that they can donate time, money, and passion to a cause that only profits a select few, at the expense of the rest of the world.


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