Caroll Spinney character transitions

Big Bird
Matt Vogel has served as Caroll Spinney's understudy for Big Bird, since the early 2000s. In most cases Vogel manipulates the puppet to Spinney's vocals (either pre-recorded, dubbed in post-production, or provided live on set), however there have been several appearances and performances where Vogel has provided the vocals for Big Bird as well, most notably in the Journey to Ernie segments that ran from 2002 to 2005.

Appearances where Matt Vogel performed Big Big's voice:

 * All Journey to Ernie segments
 * Sesame Beginnings (as Baby Big Bird)
 * Episode 4107 & Episode 4108: "The Adventures of Little Big Bird" (as Little Big Bird only)
 * A sketch where Big Bird explains to Elmo that plants can't play catch
 * A sketch where Big Bird watches Elmo show up and down
 * A segment where Big Bird and Snuffy present The Spanish Word of the Day: teléfono (telephone)
 * Christmas with the Mormon Tabernacle Choir
 * "Let's Move!" PSAs with Michelle Obama
 * The Today Show (December 28, 2005)
 * The Colbert Report (December 18, 2014)
 * Billy on the Street (with Billy Eichner and Michelle Obama)
 * Big Bird Interns at Funny or Die (with Bobby Moynihan)
 * Super Bowl 50 opening video

Oscar the Grouch
By 2015, Eric Jacobson became Spinney's understudy for Oscar the Grouch; often lip-syncing to a prerecorded vocal track by Spinney, and other times doing the voice himself.

Appearances where Eric Jacobson performed Oscar's voice:

 * Oscar's Sprout appearances on February 21, 2015
 * Oscar's April 2016 appearance on Last Week Tonight with John Oliver
 * A Sesame Street YouTube video promoting the Sesame Studios YouTube channel