Trouble in Decal Land

I recently reported that my new ultraviolet tinted window decals did not deter a few birds from flying into our deck windows. Determined to arrest this trend, I visited a local Wild Bird Unlimited store and bought more decals (after conferring with the shopkeeper.) Thus armed, I returned home, applied the eight new stickers amidst those already in place, and rested easy. For a day. Imagine my horror when I looked out that next day and saw a female house finch slam into ... a decal. One of the new ones. On an overcast day. I tended the afflicted bird which recovered and flew off after twenty minutes. But I remained shaken. Good heavens! I would sure not like to think these products are defective. But I am truly wondering what the heck is going on out there. Hopefully the finch incident was only a fluke. We will monitor the situation.