So what are the options for zerg scouting after terran have walled in? I just played a match where a guy hit me with 3 cloaked banshees like 6 minutes into the match. I had nothing for anti air, I was still going roaches and lings, my hydra den was on it's way up, but it wasn't in time to defense against this. Had I have known he had 2 starports, I would rushed anti air, but that's the dilemma, how can I find that out?
I typically scout with a drone in the beginning or i'll send an overlord over to his base to hang out. However, once he has a marine or two, my overlord or drone won't be able to stick around and by that time, he's usually walled in, so I have no way of knowing what he's doing.
Maybe this is my fault, and I should have some anti air solution by 6 minutes. I could make some spore AA towers (sorry I forgot their name) but if the opponent isn't going air early then I just wasted a decent amount of resources that are probably needed to hold off his ground army.