Any green energy source has the potential to cause harm to animals. There is no such thing as an ethical green energy source. All energy sources invariably allow the continuation of deforestation and increased carbon emissions by a rise in cheap electricity. Deforestation causes danger to numerous animals every year.
The concept of eco-friendly, or green, energy, is to have an energy source that is not harmful to the planet in any way. Endangering species of animals is harmful to the ecosystem, and therefore the planet, so an energy source that endangers animals is not really a green energy source.
While it's unfortunate to endanger animals, many of our fuel sources already do this. We should not stop ourselves from upgrading to a more renewable and environment safe energy source simply because the trend of endangering animals was not removed. In time we may develop more safe solutions for animals, but we must first deal with the more immediate problems of finding good energy resources.
OK, so do have any idea how much livestock is dying from from being hit by windmills to create wind power? A lot. And apparently all of you just want to add to the problem. Well, next time you look at a windmill think of how many birds don't see the blades of the windmill and die.