To update up to Gen 9:
Talonflame now has the highest BST at 499.
Noctowl still has the Highest Hp at 100.
Staraptor and Toucannon now tie for the Highest Attack with 120.
Corviknight now has the Highest Defense with 105.
Kilowattrel now has the Highest Special Attack with 105.
Noctowl still has the highest Special Defense with 96.
Talonflame now has the Highest Speed with 126.
Talonflame is a strong contender. It's insane speed and access to hard hitting STAB Flare Blitz and Bravebird/Acrobatics provides plenty of damage, while also having speedy utility moves to keep itself alive with Will-O-Wisp and Roost. It also has 2 great abilities in Flame Body, and the one point busted Gale Wings ability. It's Fire typing however, is a double edge sword, it's Offensive stab overlaps with its Flying for most it's super effective hits, only adding Steel and Ice, while making it 4x weak to rock and adding a Water weakness.
Toucannon is another story. While having a quite impressive Attack Stat, all its other stats are Average to Mediocre. Not fast Enough to really sweep anyone or survive a decent hit. It's main gimmick is Having Skill Link and access to Rock Blast and Bullet Seed, but with such low speed and no speed setup you can't even really use the Skill Link Kings Rock strategy without support from other Pokemon such as Sticky Web.
Corviknight is a monster. Combining impressive defensive stats with an amazing Steel/Flying Typing. While not really impressive on the offensive spectrum it does have access to to Body Press, a non stab damage move that utilizes its excellent Defense stat to do damage. Overall Corviknights very few flaws make it a strong contender.
Lastly, Kilowattrel is a respectable special sweeper. Base 125 speed only barely lags behind Talonflame in the speed department, and 105 Special Attack will deal excellent damage to most Mons. Kilowattrels flaws however comes with its very limited move pool, learning mainly only Electric and Flying type moves. It also learns very few special attacking Flying type moves: Air Cutter and Hurricane, One lacking a bit in damage, while one lacks reliable accuracy. Kilowattrel would work exceptionally well in a rain team, being able to fire off perfect accuracy Thunders and Hurricanes, as well as access to Weatherball, which turns into a base 100 power Water Type move to give it a decent coverage move. However it's inability to learn Rain dance itself makes this incredibly niche.
Overall, Staraptor debatably still holds the title of best Regional Bird Pokémon, even after all these years. It's stats best fit the role of physical sweeper of all other regional birds, Close Combat and Brave Bird have near immaculate coverage, only 19 Pokemon whatsoever can resist both of these attacks, and having Normal Stab drops this number to 5. It also has pseudo-bulk with Intimidate and Roost.
Overall I'd put them
- Staraptor
- Corviknight
- Talonflame
- Kilowattrel
- Swellow
- Toucannon
- Noctowl
- Pidgeot
- Unfezant
Hope this helps.