Need help figuring out which book series I read

I need help. I read this book series when I was around 11 or 12 and I want to figure out what it was called.

It was fantasy because it involves a Pegasus or multiple, sirens or mermaids, and maybe some other fantastical creatures. It’s set in modern day and tackles issues with environmentalism. I think the first book is about how wind turbines create issues with flight patterns of birds and the aforementioned pegasus.

I’ve been searching for this series for a couple of weeks now and can’t come up with what it is.

Thanks!

by Late-Entrepreneur-33