Not from any bird, so yes, it is a NOPE again :-) 
As you see, I found four of them and they look the same, but not the same size. 
The material could actually be same as with egg shells, but not for the same purpose.

Look again and notice, that they are turning the exact same way all 4.
BTW, they make me think about Yin and yang. :) But that has nothing to do with it.