I would think that birds would learn to recognize and avoid a threat within a generation or two.
Evolution at its finest.
Maybe so, but... I had a friend who was night watchman in the museum building that surrounds the 500+ foot tall San Jacinto Monument. On foggy nights in the fall, he would hear a series of loud "THUMP!s" on the roof. The next day he would be passing out loads of ducks and geese (with shattered bills and skulls) to anyone who wanted them...
I doubt that Darwin has decreased that phenomenon...
Never mind that those migratory birds ie ducks and dove are being shot at by hunters all the way down the Yucatan penninsula. I am sure that these wind mills will be their biggest challenge on the way South each year.