But I was motivated to research this issue last week, after I heard the tell-tale thump and went outside to find a dazed orange-crowned warbler lying face-down on my porch. I have one particular window that is apparently very attractive to birds, and although I have tried several fixes, I have yet to find the one that does the trick.
I brought the fellow inside, and laid him in one of my custom wild bird recovery suites. (A cardboard box with a tea towel laid inside, and another tea towel draped over the top.)
Within fifteen minutes he was up and fluttering, and when I took the box outside and lifted the tea towel, he flew away like a shot. Many other birds haven't been as lucky.
Those raptor silhouettes, once the primary suggestion for hapless homeowners, turn out to be completely useless. That was my experience, and I see that most expert sources admit it now, too. Bird strikes happen for two reasons:
ONE. Two facing windows seem to form a corridor. Birds look in one window, through your home, and out the other, and think they can dash straight through.
TWO. Lighting conditions turn a window into a mirror, tricking birds (which are very visual animals) into thinking they can fly into the trees and sky reflected there.
Which strategy you should take will depend on which of these cases is true. If you have a reflection problem, for example, it won't help to pull the curtains. In fact, it may make it worse, by providing a solid background to the window. But if you have a fly-through illusion, drawing the curtains will fix the problem by blocking the birds' view of the other window.
Both problems can be solved by these clever, mostly-transparent, UV-reflecting window decals that a friend told me about. You can buy them online, and they are also sold at many wild bird supply stores. Birds can see well into the UV range, so these reflectors stand out like beacons during the day. My friend's father, an avid feeder of birds, says they have worked perfectly for his house.
Another solution to the reflecting problem is to let that particular window get dirty. A dirty window doesn't reflect very well! (Great excuse, right? You're saving wildlife!) You can also solve the problem by hanging gauzy curtains or taping tissue paper to the OUTSIDE of the window.
If it's an important window, you can compromise by hanging netting, wind chimes, or mylar streamers outside the window. These serve to visually block the window from the bird's perspective, and are a distraction that may ward off smaller, shyer birds.
Another possibility is this stuff called CollidEscape, which is apparently only being sold to commercial building owners at this point. I'm intrigued, though, because it's transparent from the inside, but opaque from the outside. And apparently it's removable, too, which is great for us renters!
Photo credit: Flickr/Kyle Slattery