DH has tried shooting water at them but it didn't work. They get in among the branches and are hard to pinpoint. We have torn down nests we could reach but they just go across the street and build another.
They nest in virtually any tree or shrub we have. If it was one tree, that would be no problem. DH has enough yard work without having to trim back every tree. Some are too high or are on too steep of a slope to get at to trim. We have a huge pile of yard waste in the yard as it is.
DH got a mechanical owl. It moves it's head. That has been helpful but we don't know how long it will work.
You know that normal birds quit nesting in July. The mockingbirds keep producing like chickens.