Ive flow DJI drones since 2012 and never once been attacked by birds. I’ve seen vultures frequently, fly around in circles above the drone, I’ve had waterfowl zip past, a little close for comfort, I’ve seen hawks look on in curiosity, sea gulls...
Unfortunately, it appears that metal backing is essential to ALL retroreflective material, so there is no "if."
Metal Backing:
The metal backing, specifically the hemispherical aluminum coating, is crucial for the retroreflective properties.
I know very little.
I do know that if the retroreflective material is metal backed, and it is placed over the GPS antenna, it does degrade it. There was another thread on the topic.
I don't know how much reflective stuff is adequate to deter...
The same could be said for non-native Norway Rats in New York City. They define many neighborhoods in NYC and thrive in a variety of habitats. Their nativity should be irrelevant. They've been part of the environment for hundreds of years...