Bird Safety

Luckily, my cat, Blue, isn't interested in birds. He's hell on chipmunks, but not birds. This morning, I received this email from a friend. 
"Talking about cats, Luna had become a bird killing machine (one, sometimes two, a day). In desperation I went on line and found a site - “Bird be safe.” Apparently birds can see bright colors - I bought a simple cotton collar from the site and- voila- no more dead bird gifts. I mean none. She seems almost proud of her collar and, although she can take it off easily, she generally doesn’t. If you have friends with a similar problem you might want to pass this along." 
pet cat kills between one and 34 birds a year, while a feral cat kills ... 
It's well known that cats kill millions of birds a year--Estimated at 3.7 million. If there is something that works to cut down on that number, it has to worth a try.
Want to Stop Your Cat From Killing Birds? Dress It Up Like a Clown
 If any of you try it, I'd love to hear back.

P.S. I got this from a bird-rehabilitater of the first order.
"That bright collar sounds like a fine idea. Yes, songbirds and many others can see ultraviolet light, for one thing, which creates a kind of neon glow. For another, most diurnal birds have at least four types of color cones in their retina, RGB and violet. We have three - RGB. Other non-primate mammals, most of them, have two- blue and green. Birds react strongly to color for display and possibly territory protection, and in hunters, in getting food. What a simple solution!"