*facepalm*
Fearnado man, c'mon. It parries projectiles and that's one of the easiest to parry in the whole game. You CAN get punished in recovery on it if he's close enough, but you can choose to MB for your own full combo.
Unfortunately, parrying birdarangs with trait on doesn't grant fear meter currently (bug, most likely).
Fact is, he CANT just spam birdarangs and get free pressure, and Crow has big punishes for everything Robin does, including both of his wakeups. I'd say Crow wins this one, especially once the bug is fixed. He's going to WANT to stop throwing birdarangs.