Vertical wind turbines would greatly reduce the relatively small share of bird deaths.
As for those huge mirror arrays to focus sun light on the top of a tower that fries those birds, I hate those - it's more of the "bigger is better" fallacy incorporate thinking. They just want a way to bill you for sunlight when it's free.
I saw that more birds deaths come from oil pits than windmills, but the google results are not well-vetted on everything. My first guess was pesticides, which not only directly poison them but also their food chain (think bees pollinating plants that provide a source of seeds for the seed-eating bird species). But while much bigger than renewable energies, pesticides and the whole fossil fuel energies were well behind windows and cats.
Around here our Animal Control Officer warns us that Coyotes and other predators hunt your outdoor cats and to bring them inside - so keep them inside for both reasons!
"I'd rather be an American than a Trump Supporter."
- xongsmith, 5.7d