What ARE birds?

It was more like,
In an attempt to ask gatrs question in a "are ______ birds?" format I figured

If there was a name-basis to what birds are, similar to schazer's birds, then all organisms that were birds would share an exclusive trait, but if birds are not determined by a characteristic of their names then there is no such thing as a taxonomic trait exclusive to birds and thus there are no organisms that fit the given description - hence them not being birds.

But it could be said that the exclusive taxonomic trait is that they all belong to a list of names of names of the given organisms - hence the extra caveat.

But also by that point I realized I was getting too far away from the spirit of bird-game and too close to playing Nomic.


Are birds?
Are birds?
Are roses birds?
Are sunflowers birds?
Are fungi that are not mushrooms birds?