This is a bit of string tied around perch hardware to keep Peanut from hurting himself. As you can see, the Finsters have pulled some of it inside their cage. I used to use a strip of cloth (scroll down a bit to see), which also was a pretty good toy. But this string is even better. I've seen all the Finsters playing with it — even Sally! At first the Societies tried to fly off with the string bits to make a nest, but now everybody chews at the string. I guess it's a little like preening.