Sometimes the bird is "just stunned" and eventually "recovers" but often dies later of internal injuries or other injuries that render it less able to survive in the wild.
There ARE solutions! One is BirdTape from the American Bird Conservancy. I just ordered some to install on the windows of our new Garden Room. It's inexpensive and research-based.
To read about ABC Bird Tape (and order it) click here
For more on the seriousness of the problem, check out this article in the Birds on the Brain blog. Even though this piece is about Duke University in the States, the problem exists EVERYWHERE, even here on little old Gabriola Island!