Here's my rankings:

1. Rowlet (He's the most personable, especially when he takes care of little meltan. He might not be the best battler, but I like the funny and adorkable personality quirks of the owl.)
2. Shiny Noctowl (He's the smartest of Ash's regional birds, who maximizes his psychic potential (should have been a Psychic/Flying type. He may not be the strongest battler, but his status as Ash's only shiny and high intelligence makes up for it.)
3. Pidgeot (She, read somewhere long ago Pidgeot was a girl though not confirmed, is the OG bird, probably Ash's most loyal Pokemon, who never betrayed him or turned her back on him, despite Ash's 25-year absence. That's )
4. Hawlucha (He is probably the most chivalrous and fiercest pokemon that Ash had. He presents the new qualities of a regional bird that distinguish him from Talonflame. There's just a lot of character behind the pokemon.)
5. Swellow (his battle record, the bird is Ash's best battler among the regional birds)

What are your rankings? Since these are my top 5 for personality and ability, this is a personal ranking and everyone has their own