I just discovered the miracle of "post-it laveling & coverup tape for making a crisscross design over my picture windows; every year I get several bird hits and sometimes they can recover, but not always. Hope this helps. VERY easy to apply & not expensive.
Here are a few options: Set up a window feeder, it will keep the birds safe from striking the window and provide close views of them feeding. If your feeding station is in the direct vicinity of a window, move it to within three feet of the window. Install window screens. Decals and stained-glass decorations are moderately successful. Hanging vertical exterior tape stripes across the window at 4 inches (10 cm) intervals.
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