Birds

We have a door in our apartment that goes to nowhere. Really. It was supposed to be an outside entrance (vestibule) to the back of the house, but the people who lived here before couldnt decide if they would use brick or wood to build the steps. It became a HUGE argument, and needless to say, the steps weren't built, and the door goes to nowhere. Anyway, this spring, a couple of sparrows made a love nest and raised some little ones in there. I enjoyed watching the progression of eggs to chicks to flying little birds. I assumed that they all left the nest this summer, but it seems thats not the case anymore.

It looks like one of the babies has taken to our late night life. When I get home from work around 6ish, I can hear one bird in particular chirping away. Not really a big deal, the sun is still out. Strangely though, usually around 8:30 when the sun goes down, the bird goes NUTS. Right now, he's happily chirping in the outer vestibule making it known that he wants to be night bird. Or, in bird, a night owl.

I think its very strange that he chirps in the dark. Is he blind? Is he just a happy bird? I originally thought he was in trouble, but a quick look through the window with my little LCD flashlight, showed nothing but a dark little sparrow, hanging out in the corner eave. Whats his deal? I didn't think birds chirped at night in the dark. Anyone have incite to this oddity?