I've had mockingbirds in my yard for the entire time I've been in this house - it was a cow-pasture before I had my house built. They've never, ever acted agressive towards humans. That's not to say I doubt your story. Not at all. From my experience, both in the north and south, mockingbirds are the "bluejays" of the south...aggressive to the extreme.
I imagine nitrogen is completely correct.. pretty much any non-game bird is federally protected..this means your options are S.S.S., attract other birds to your yard that will distract it, or make such a nuisance of yourself to animal control that they rid you of the problem.
I think Cromlech, even as a joke, has a valid idea. My own first thought is to hang up a bird feeder or five in your yard. If you attract a few other songbirds, your mockingbird will be too busy attacking the other birds to attack your wife... bonus is that you get to watch the other birds, most of which will be much friendlier than mockingbirds.