blackbird singing in the dead of night

Actually, it's a mockingbird. It is nine minutes to midnight (yes, I have been puttering with computer funthings, and my sweetie is out of town and not here to gently push me to bed), and our resident Mockingbird of Insanity is chirruping away. I love mockingbirds, and songbirds of all kinds, but I don't understand why this one is singing at night. They don't, normally, do they? This one does.

I'M going to sleep now.

edit 14 Sep 06: I since learned that night singing is a "feature" of mockingbirds well known to many people other than me. I guess I just never happened to be awake to hear one before. Live and learn.