To know How to Stop Birds from Flying Into Windows ? Bird-window collisions are a common problem, especially during migration seasons. Birds often mistake reflections of the sky or trees in glass for open space, leading to potentially fatal impacts. Fortunately, there are simple and effective ways to prevent this. One of the best methods is to make your windows visible to birds. Applying window decals, tape patterns, or UV-reflective stickers can break up the reflection and alert birds to the barrier. These should be spaced no more than 2 inches apart horizontally and 4 inches vertically to be effective.