"The Window Alert Decals are great and we have not had any birds hitting our windows since we put them on. They are also very easy to apply and remove for window washing. Great Product and a Great gift idea for friends." -Mary, Hummingbird Window Decal Customer Prevent bird deaths!WindowAlert decals help prevent wild birds from accidently striking windows. Each decal has a special coating that reflects ultraviolet sunlight. 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. For best results, the decals should be placed on the outside of a window. As a rough guide, we recommend one decal for every 3’ x 3’ section of glass.2 Sets of 4 low-tack decals. The Hummingbird decals measure approximately 4” across.
