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Saturday, September 20, 2014


Last month I are posted on:


In summary, I reported:

  • There may be up to 400 billion birds on Planet Earth.
  • In the U.S. alone:
    • Cats kill half a billion birds/year.
    • Glass windows:  almost a billion
    • Traffic:  100 million
    • Electrical transmission lines:  around 174 million
    • Agricuture:  67 million
    • Wind turbines kill around 250.000, or 0.050% as efficiently as cats.
    • If some day wind power increases by a factor of ten, that would equal 2.5% of cat kills.
    • If some day solar farms produce as much as electricity as wind farms, all those facilities would amount to 10% of cat kills.
    • Should we eliminate cats from our society?  There are 74 million to 96 million cats as pets in the U.S., and 70-80 million dogs.  Dogs aren't as capable as cats in reference to birds.
    • Fossil fuel power plants kill ten times more efficiently than wind farms.
    • Windows and buildings kill tens times more birds than cats.  We certainly won't stop using windows nor constructing buildings.

Well, Susan Kraemer of Renewable Energy News just reported:

  • There are 5 billion small passerines (song birds) in North America.
  • Somewhat fewer than a quarter million passerines collide annually with wind turbines in the USA and Canada.  
  • This is about 0.01% of the population of passerines.
  • 30% of passerines (right) annually die of natural causes.
  • However, the size of windmills has changed from the faster-turning small kW turbines of the 19080's to the 1-3 MW turbines of today, which are out of the hunting range of raptors, but lower than the migration corridor of small passerines.
  • Bird kills have accumulated from the earlier days.  Latest studies show less of an effect on birds.

However, two of the three comments to that article indicated:
  • The study was paid for by the American Wind Energy Association, which is a clearly biased organization.
  • Raptors (right--eagles, hawks, etc.) do get killed by wind turbines, and their reproduction rates are much lower than passerines.
So, maybe this issue will continue to hinder solar and wind farm development.


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