Hang CDs in Cherry Trees

We have birds and squirrels visit our cherry tree. In order to have any cherries ourselves, I take old CDs, tie one end of a string through the center hole, and tie the other end on the tip of a tree branch. A gentle breeze will twist and turn them, causing the critters to leave the cherries alone. I don't put them out until just before harvest because, like anything else, once the critters become used to them they are useless as a deterrent. As soon as the harvest is done, I bring them in to keep until next year.

Where do I get so many CDs? I accumulate them all year long and even have family members hand me theirs. Some are old broken CD's or DVD's. Each new electronic device has a CD to give directions, making the old ones obsolete. By the time cherry picking time is here, I have quite a stack of them.