well. lets look at the stats
-----------noctowl--------------- crobat
HP 100-------------------------85
Atk 50-------------------------90
Def 50-------------------------80
Sp Atk 76-------------------------70
Sp Def 96-------------------------80
Spe 70 ---------------------- 130
so noctowl has more HP and slightly more SP attack but all in all crobat has better defence and SP defence (not that that matters much.) but look at that 90 attack. and 130 speed to! crobat is the answer. to me a good ingame moveset would be cross poison, mean look, theif, and fly.
hope I helped!