I don't have bird houses so I don't have to worry about wasps getting in them. Birds can nest in the trees and bushes.
I HATE wasps. They're evil little devils; and I swat them whenever the opportunity strikes. The water hose makes for an effective weapon as well. I've heard bars of soap discourage wasps but I've never tried that. Fake, paper hornet nests don't work either; the wasps built up in it. Raid wasp spray is probably the best brand of wasp killer; even though it's not as fast acting as it used to be. IMMEDIATELY after you spray a wasp nest, you run as fast as you can. Wasps don't drop to their deaths as fast as they used to, and some even escape.
