Birds don't see glass the way we do — a window either looks like open sky because of what it reflects, or it looks like a clear flight path straight through a house. Either way, the bird doesn't register it as a solid object until it's too late. Mesinurs Window Decals work by breaking up the illusion of open clear space reflected on windows. When decals are spaced closely enough across a window, birds perceive the surface as a barrier rather than open air and steer around it, the same way they'd naturally avoid a dense hedge or fence line. This is why spacing matters more than any single decal's design — a properly spaced pattern is what actually prevents strikes.