CLOSED: what is the bird doing

My friend has a bird that I believe is a female House finch - who jumps up and hits the window of her French door. It keeps doing this. Reflection maybe so she covered the window pane up, the bird went to another side of window and did the same. Has been at it for over two weeks. Has red under the tail, going to try for a picture later.

Is it reflection and mating or what any ideas?

You can probably rule out female House Finch, since she has no red on her. I've never heard of a finch doing this behaviour, but birds often surprise me. Any other parts of the bird red?

Is your friend located in your area? Even without a picture, this can help with ID. I am wondering if a female Northern Cardinal if this is not in California. Cardinals of both genders often beat up on their reflections. I'll post a picture of a female we had last summer. We pulled the car out of the garage to help the Barn Swallows, to give them peace, but it caused another problem. :)

No, its not mating, but more than likely defending territory. As your friend is experiencing, birds do not recognize glass as being glass. The lighting plays a large part of that. She can cover up the other side, or point an inside light toward the window.

thanks - no other red on bird. She has tried taking a pic but is not having any luck. We are in California, she is North Hills. The bird or birds are still doing it. She tried covering up the bottom two areas of the French doors (12 panes) but lost patience and took some of it off, wont stay on and does not look good. shame. Ill try getting a picture.

thanks for info

As one who prefers birds over much that is man made, I cannot help with the looking good part. :)

Here is a site with more suggestions to prevent the window attacks. They brought up the lights inside the house.
http://www.wildbirds.com/dnn/ProtectBirds/WindowHazards/tabid/681/Default.aspx

A poor quality picture is better than none. Birds are keen at sensing movement, so if she moves too close to the window too fast, they will notice that.