Thought that this might be worth mentioning for those that may have missed it…
I recently read an informative article from David Sibley’s blog (Sibley Guides Notebook) about various window treatment methods to help reduce bird collisions. I think most of us that have bird feeders in our backyards have witnessed bird collisions into our windows or glass doors. Just the other day there was a dead House Finch in my flower bed. I suspect that he collided with the window I found him under and lost the battle.
Here is a quote from Sibleys blog:
“Estimates of the number of birds killed in window collisions each year in North America run as high as nearly a billion birds. It's the biggest source of direct human-caused mortality in wild birds. But a simple means to prevent birds from hitting windows on your house or office could be in your desk drawer, or at least as close as your local office supply store, costing only a couple of dollars and a few minutes of your time. This needs further testing, but it appears that an ordinary yellow highlighter can be used to draw lines on the window, and those lines may be visible to birds, warning them away from the window, but are almost invisible to people.”
While there may still be unanswered questions in his experiments, it sounds like he is on the right track with this –