It's mating season and the birds are defending their territory. If you find a full page magazine picture of a human face and tape it showing outward, the birds will stop. Used to have this problem all the time, and this stopped it immediately.

I had a robin that made himself bloody whacking into my patio door...even with the drapes drawn, he was still at it..finally out of desperation i cut long tin foil strips and taped them all over the glass..not pretty, but did the trick till he went away! Don't ever want to deal with that again.

I have that problem a lot with cardinals. I tape a large picture in the window for awhile and they stop. We are always having doves fly into the windows.

Piepatch,
Thanks for the tip. A sparrow attacked my mirror recently.

When you buy chimes, make sure they do not have the little clear figures on the bottom. I made that mistake once and it cost me a window. I take them down off the windows in the winter now to avoid the problem

I put a CD shiny side out.

My mother has sliding glass doors and the birds would fly into the glass so she put a piece of construction paper up (red). Just taped it to the inside. Still had birds crashing into glass so she called me and told me what was happening and what she did. I told her to take the RED paper down and use white. You have to use white or very light. Problem solved.

The problem we have with the robins is that she wants to build her nest every year of the front door. I removed the mess every morning and it took weeks to get the hint across. This year she finished the nest before I could catch her and I removed the completed nest using gloves and a cardboard to a nearby tree. She didn't use it of course but she never came back for another try. I think letting her finish it and then moving was the thing that was different. I feel bad about all the work she does but the mess is so bad we can't sit out on the porch with her overhead. We also have a wall of windows in the back of the house and birds thump into them all the time. I can't reach them to do anything about it.

We have robins or swallows that always want to use the top of our front porch light as their nesting place. So every year I have to put crumpled foil on top of the light. This year they even used a giant dried hydrangea flower as part of the nest before I got the foil up.