I'll wager that cars and airplanes kill more birds than these towers. Add in cats, hawks, trains, electricity, weather, poison, and the natural aging process, and we've virtually guaranteed that 100% of all birds will be killed off within their lifetimes.
That is positively terrifying, isn't it?
Back on topic- I saw a couple of blades go by on railcars a few weeks back- the train was moving at just a couple MPH, and it took me a while to realize what they were- the pictures truly don't do them justice. They are just enormous. I haven't seen larger pieces of equipment outside of a steel mill. Very impressive.