Season 7, episode 882: Big Bird finds a lost boy/Winnie Wiggins introduces herself.
https://muppet.fandom.com/wiki/Episode_0882
Finally, a confirmed performer for Winnie - the late great Richard Hunt! Notice how some his early Muppet roles were Large Lavender Live-Hand characters - Winnie Wiggins, Headline Howie, and the frustrated librarian in the "No Cookies in the Library" skit. Then he rose to fame as Don Music, Forgetful Jones, Gladys the Cow, Placido Flamingo, and Sonny Friendly.