Save the Robin

We have a breakfast nook where we can sit & eat while watching the trees, squirrels, birds, sunset (if at the right time) and the little flower bed just outside. In the midst of the flower bed is a black pole with 2 painted glass balls hanging from the top and a clematis wrapped around the bottom in the summer. Occasionally a bird will perch on top.

Last summer we noticed a hummingbird hovering around the glass balls, which do look similar to some of the hummingbird feeders we have seen in stores. The little bird came over to the glass & bumped it a couple of times. We thought perhaps it saw its shadow & thought there was another bird there. We have noticed that they seem rather territorial.

This morning I was in the kitchen and heard a big thump. Actually, there were a couple of thumps. A few seconds later there were 2 more thumps. I noticed a robin perched on top of the pole. Then it just turned and flew into the window glass and up the glass and into it again at the top. This happened over and over. Finally my husband came into the room to watch it. He agreed that the robin probably saw his reflection and was attempting to attack his foe. After about 10 minutes of this the robin left.

I know there are decals you can buy to put on sliding doors or other big panes of glass so that humans will know it is actually glass and not an opening. What can we do to protect the birds? I was afraid the robin would break its beak or knock himself out.