Since 1969, "Sesame Street" character Big Bird has been described as being what age?

Big Bird is a Muppet character designed by Jim Henson and built by Kermit Love for the long-running children's television show "Sesame Street". An eight-foot two-inch (249 cm) tall bright yellow anthropomorphic bird. Caroll Spinney originally performed Big Bird from 1969 to 2018. Matt Vogel began as an understudy in 1996 before becoming the character's full-time performer in 2018.

Big Bird's appearance has changed over the years, as has his personality. He originally had very few feathers on top of his head; his body feathers were also more shaggy and unkempt, and his body was not as rounded and full as it is now. His personality was more dopey and "bird-brained" than it later became.

He gradually got more feathers on top, giving his head a more rounded appearance, and developed a blaze-like crest of lighter yellow feathers above his eyes. His body got fluffier, rounder and more well groomed as well. His personality developed over time from being a dim, slow-witted character into the childlike innocence he is known for today. Although all the "Sesame Street" Muppet characters are technically ageless, Big Bird is psychologically written to represent a six-year-old.