So as you can see, Staraptor is better on the offensive. It has a massive 120 attack stat to pair with powerful moves such as STAB Brave Bird and Double-Edge and Close Combat. It's ability Reckless even boosts Brave Bird and Double-Edge to higher levels of power. Or you can choose it's other ability, Intimidate, to soften physical blows as it has mediocre defenses.
Pidgeot's stats are quite lackluster. It has decent 83/75/70 defenses, but it only has 80 attack and 91 speed compared to Staraptor's 120 and 100, respectively. It also has a very limited movepool; it only gets Bug, Flying, Normal, and Steel coverage in it's viable physical moves, leaving it walled by Steel types and Rock types with high defense. Staraptor has Close Combat to take care of those, giving it another advantage over Pidgeot. Pidgeot also has near useless abilities.
tl;dr: Choose Staraptor, Pidgeot has almost nothing over it.