I have a very loose knowledge of pokemon.
That said, going try my best to make some sort of workable all bird team, if that's even possible.
Not only is it possible, it'll probably be pretty easy
Here is a list of all the bird Pokemon that are confirmed pre-release
Corviknight (Flying/Steel)
Cramorant (Flying/Water)
Farfetch'd/Sirfetch'd [Sword] (Normal/Flying -> Fighting)
--
Hoothoot/Noctowl (Normal/Flying)
Togekiss [Debatably a bird] (Fairy/Flying)
Natu/Xatu (Psychic/Flying)
Wingull/Pelliper (Water/Flying)
Pidove/Tranquill/Unfeazant (Normal/Flying)
Ruffflet/Braviary [probably exclusive against Vullaby] (Normal/Flying)
Vullaby/Mandibuzz [probably exclusive against Rufflet] (Dark/Flying)
Hawlucha (Fighting/Flying)
The top mons are new ones or have new Evos.
Definitely recommend Corviknight to help alleviate against Flying weakness (specifically Rock and Ice since Steel is Super Effective against them)