Thanks!
Yes you are right! Just very much not studied.
For example, I'm very interested in what the great tits (ooh...why are these birds so indecently named? :D ) say.
After all, they have so many different sounds! And they constantly communicate with each other.
I tried to search for the meaning of their sounds, but I did not find it :( Maybe you know something about this?

btw! I recently found out on a very interesting experiment where the great tit transmitted information to other birds about tasteless food.