Everyone needs to retire at some point... Amazing he performed this role for 50 years maintaining his wide-eyed enthusiasm. Equally amazing is the number (millions upon millions) of lives he has touched over that time with his performances.
https://www.nytimes.com/2018/10/17/arts/television/sesame-street-big-bird.html
https://www.nytimes.com/2018/10/17/arts/television/sesame-street-big-bird.html