Out of all the regional birds, the best one competitively is Staraptor. Staraptor has nice 125 attack an acceptable 100 speed, it gets Close Combat which is a solid move, it also get Double-Edge and brave Bird and the ability Reckless which increases their base power to a wrapping 144 base power, thats stronger than hyper beam! You can make this set even stronger with a choice band or life orb to skyrocket its already high attack. The only problems with staraptor are its frailty and not being fast enough to outspeed common Pokemon, it's frailty combined with what basically is a set that guarantees that you'll always lose health when you attack isn't really good. it's still a solid. What I just listed was its overall viability.
AG
I'm going to assume that is is Nat dex ou since staraptor isn't in gen 8. It stands absolutely no chance against literally anything in there, almost everything outspeed and defeats it.
OU
I'm going to assume this Nat dex ou since staraptor isn't in gen 8. It's biggest threat is regieleki which is a very common Pokemon, it also can't outspeed many other Pokemon and it can get OHKOed easily. staraptor works best in nat dex UU.
Staraptor @ Choice Band
Ability: Reckless
EVs: 4 HP / 252 Atk / 252 Spe
Jolly Nature
- Close Combat
- Double-Edge
- Brave Bird
- U-turn
Hope this helped?