You are looking (photo below) at a wall of glass, the entire south side of the National Eagle Center building in Wabasha, Minnesota. Lots of reflections in what is plain old window glass. The building is 100 feet from the Mississippi River, and faces due south, into the teeth of spring migration.

And how many birds die here each spring season? It used to be about 100, the small warning decals here and there on the glass (look closely) making little difference. That number has been reduced by 80 percent in recent years by one simple change: All — ALL — the lights in the building are turned off every night during migration months. Even security lights go dark. (A close look also will reveal the interior lights on the high ceiling.)

Eagle Center staff discovered that the birds — mostly night migrants, as is the usual case — were attracted to lights. Whatever was applied to the glass made little or no difference in the dark because the birds could see neither glass nor warnings. The birds flew to the light, even the smallest glimmer. 

Putting the building into dark mode made a big difference.