WindowAlert decals help prevent wild birds from accidentally striking windows. Each decal has a special coating that reflects ultraviolet sunlight making them very visible to birds which help to reduce window strikes.. This ultraviolet light is invisible to humans, but birds see it as a brilliant glow much like a stoplight. To the human eye, the decals appear as frosted or etched glass. The decals are designed to be placed on the OUTSIDE of a window.  As a rough guide, we recommend one decal for every 3' x 3' section of glass. Reapply decals every 6-9 months.

WindowAlert decals stick to most windows using static-cling. There are 4 decals in a package except for the one with the assorted leaves, which has 5.