As far as I looked, these are the Pokemon that I consider to be "birds."
- Pidgey, Pidgeotto, and Pidgeot
- Spearow and Fearow
- Farfetch'd
- Doduo and Dodrio
- Articuno, Zapdos, and Moltres
- Hoothoot and Noctowl
- Natu and Xatu
- Skarmory
- Murkrow and Honchcrow
- Lugia (kind of borderline not birdy)
- Ho-oh
- Taillow and Swallow
- Wingull and Pelliper
- Swablu and Altaria
- Starly, Staravia, and Staraptor
- Chatot
- Togekiss (kind of)
- Pidove, Tranquil, and Unfezant
- Archen and Archeops
- Ducklett and Swanna
- Rufflett and Braviary
- Vullaby and Mandibuzz
- maybe Delibird
Sorry for the long list but I hoped it helped anyway!