You should swap Pidgeot by Staraptor or Toucannon, way better.
Maybe use Decidueye? He's Ghost/Grass but is definitely a bird.
Appears that you are using only mons that you finding through the game. So, for Serra, I think that your best bet is to mine a Aerodactyl fossil, I really don't know if this mining becomes available before Serra, but it should. If you are taking traded mons, along with Aerodactyl, you should take Archeops as well. Both mons will outspeed her and, besides having ice disadvantage, have rock advantage + high attack stats, so Rock Slide/Throw Serra to the ground, baby.
More names: Crobat (I'd definitely swap it with swoobat), Gyarados, Scyther, Dragonite/Altaria/Salamence, Xatu, Drifblim, Chatot (always fun, must have), Gliscor, Mandibuzz and Hawlucha.
Good lucK!