It's not the main point of this article, but I frequently see sources mentioning wind turbines as a cause of bird deaths. Clearly, it's true. Wind turbines may kill over half a million birds per year in the US[1]. That said, apparently cars and other factors like window strikes against stationary buildings, cats, cell towers, and electric wires kill orders of magnitude more birds[2]. Big numbers sound horrible without perspective...
[1] http://onlinelibrary.wiley.com/doi/10.1002/wsb.260/abstract
[2] http://www.sibleyguides.com/conservation/causes-of-bird-mort...