Caroll Spinney has played the part of Big Bird from Sesame Street since the characters introduction in 1969. Caroll Spinney is 80 years old now and still plays the part. I found an interesting diagram of how the Big Bird suit works.
1. Spinney uses his right hand to operate the mouth.
2. There is a small LED light that Spinney can position any way he wants.
3. A fishing line is run through an opening in the neck so Spinney can move the right hand of Big Bird.
4. Big Birds script is pinned where Spinney can see it.
5. Spinney has a 1.5″ screen strapped to his chest that shows exactly what is shown on the Television.