Hi Tom,

Your cardinal is trying to chase away it's the new bird in it's territory, her reflection.  Unless you can prevent her form seeing her reflection by putting something in or on the window, she will likely continue for a while.

I have seen both N. Cardinals and N.Parulas do this before.  While working at a Wild Bird Center and nature centers we get calls about cardinals during their nesting season on a regular basis.

Good Luck!

Naturally,
Mike Callahan
Nanjemoy, Charles County, MD