What kinds of birds are these?
Is it the migration season for these birds?
Do you remember noticing this problem when you bought the place? Maybe the future owner won't notice either. Sellers' senses get pretty acute when the place goes on the market. Buyer's aren't nearly as critical about the property.
Trying to control birds -- forget it. Decoys don't work (tried 'em), noise doesn't work, pellet guns will simply break windows and risk a law suit when little Johnny gets hit. Same deal with poisons. The risks outweigh the benefits, of which there are none.
Cats might help, but this sounds like an urban setting. Well, the urban setting was once natural, and the birds were there first. If not, then they are being attracted to the food supply, which isn't simply stale bread. Grass seed, garden seed and tree bugs are probably the big attractors. Maybe people in the neighborhood put out seed for the birds, as this hobby has grown over the past few years.
Hey, at least it isn't black bears thrashing through your trash or pumas snacking on neighborhood poodles. Not that I have anything against feeding neighborhood poodles to the big cats
Looks like you're stuck with the garden hose treatment. Either that or a really big tarp over the house. Saran Wrap? Hopefully, the birds will move farther south as the season progresses. Unfortunately, Vegas might be their favored wintering grounds.
I like the idea of selling the birds with the house. It's nature! How wonderful it is to wake up to the sounds of birds! The new owner can put in web cams and start a Chicks Galore site and maybe make a few bucks on the side. Combine it with cats and you get, well, you know. Birds make a great emergency food source for the survivalists out there. Squab is a delicacy in some parts of the world. Birds renew the ozone layer too! (A whopper, but what the hey, it's sales.)