Vegetarian In Boston Maynard S. Clark's Veggie and Boston Blog talks about vegetarian topics AND Boston-related topics, often intersecting them interestingly. Maynard S. Clark is a long-time and well-known vegan in Greater Boston, who often quips in his 'elevator pitch': "I've been vegan now for over half my natural life, longer than most human earthlings have been alive."
The SOLUTION - the ENGINEERING SOLUTION - is to SHIFT THE PLANE from rotating the blades in the VERTICAL plane to rotating the blades in the HORIZONTAL plane.
Let's THANK animal (bird) advocates for raising this issue, but let's insist that future design integrate this concern from the outset.
Lots of blade building has already gone ahead, production machinery has been purchased, and workers have been hired and put on the assembly lines.
I raised this concern nearly a decade ago - and suggested this solution about 3-4 years ago.
Advocates didn't see that as an issue at that time (or some merely said, yes, the blades shouldn't hurt the birds).