From my state birding listserv:

We've all heard (or experienced) those stories of the testosterone-laden male Northern Cardinal attacking it's reflection on a window.

I've got a new twist on it.  I was atlasing along Red House Road.  I start hearing a knocking sound back towards my car parked along the road shoulder.  Turns out it is a cardinal, who (in record time?) has discovered his reflection in my passenger side rear view mirror (he eventually found the bird on the driver's side as well.)

He took some great photos! This is the thumbnail of the best one:



Go see the rest of them and look at the full-size versions ... they're really hilarious!


Those cardinals really are weird. A couple of years ago I was walking in the park by the lake and heard a thump in the direction of a tot lot about 50 or 60 yards away. Then I heard it again. I looked over, and saw a cardinal fly straight up off the ground and crash into the bottom of the metal slide!  I didn't have my digital camera yet, so all I could do was stand there watching through my binoculars in amazement as he did it over and over. 

The first time I ever saw a cardinal do that was the last summer that I lived in my wonderful house in the woods. First thing every morning -- and the sun rises early in the summer! -- I'd be awakened by the loud crack of a cardinal striking my bedroom window as he attacked the "rival" that he thought was invading his territory. He'd bounce off, fall a few feet, flutter and catch himself, land on a branch of the tree outside the window, and do it again. And again. And again and again and again. Every morning. It was nerve-racking and I tried everything I could think of, but nothing I did stopped him. I finally solved the problem by moving. It was one of the few things that made me glad to leave!