"The biggest bird killer in the US (and likely, the world) is #Cats. Outdoor cats kill somewhere between 1.3 billion and 4 billion birds a year in the US alone. Let’s put it this way: for every one bird that dies in the blades of a turbine, domestic cats are dragging roughly 4,000 back to the porch."
Article: The harm caused by wind turbines isn't nearly as bad as you think...

