[Craig S]

Around 4 pm on 6 June we noticed a Great Crested Flycatcher in our tree, was a great photo op. Then he flew right at our window, pulled up just before hitting and started beating on the window with his feet as he hovered. We thought this was really strange behavior and got some pictures as he repeated the process over and over until last light at about 10 pm, at which time he perched in our tree, called a few times then took off. He did leave several times during the course of his antics but always returned within about 20 minutes. Once he dove from our Hummingbird feeder right into the window, thankfully it was only a distance of about 2 feet. He didn't go to any other windows along the front of the house until I opened the front door to try and scare him off, I left the inside door open and he then began banging on the storm door glass.
We were up at 5:30 am on the 7th and could hear him beating on the window. He continued doing this until around 7 am, departed only to return around 9 am and repeat the process for another 1/2 hour, he has been gone almost 2 1/2 hours now and we hope he has found something more constructive to occupy his time.
At around 11 am a male and female Baltimore Oriole did the same thing for a short time.
We have had American Goldfinches and Pine Siskins land on our window sill and peck at the glass before but nothing like this.

[Steve Schoech]

Standard story ... territorial bird sees reflection of self, attacks perceived intruder. Happens regularly with many species showing this behavior although some more than others. Primarily, but not always so, done be males.

[Craig S]

Thanks for the explanation, we sort of thought that it was a territorial thing at first, but, it continued for 6 hours last night and 4 hours this morning. His attacks were always at the top of the window, starting on the right side of the window, which is three panes totaling about 10 feet in width. He would repeat his attacks across the the length of the window from right to left. Then start over again at the right side of the window. It was very bizarre.

[Steve Schoech]

I've had cardinals that could go one for day after day and even year-to-year ...

[Craig S]

It would drive me crazy, the constant thudding on the window was a little annoying, but we were certain he would injure himself and would cringe every time we saw him dive off the tree toward the window.
We are really hoping he has moved on.

[AlainaLee]

we had cardinals that would do that.. and on our car mirrors.. would leave scratchings and poo all over the cars.. would happen for months straight each spring

[Craig S]

Hmmm I think I am getting where the term bird brain originated from. This was first experience with an obsessed bird and hope he takes his obsession elsewhere.

[Craig S]

Looking at the window today we noticed the bird had smudged the window and left little footprints on the window in several places.