I’ve had a mild amount of success asking some nature photographers if they would be willing to make a few of their photos freely licensed so that they can be used on Wikipedia articles.
I found the peachicks on Commons by searching "peacock" and then following categories up the tree. If people use the wrong search engine with naïve search terms, I don't know what to tell ya.
This is a parallel example of why reference librarians are still worth consulting, because they will guide you to the library's resources and databases, and demonstrate how to use search queries.
Wikimedia is a fantastic resource.