Alfred Duck
From Muppet Wiki
Alfred Duck has been a recurring background character on Sesame Street since Season 33 (though the puppet itself has been used many years before). He has been a recurring patient of Gina's since Season 35.
His design is very similar to the white version that also appears on Sesame Street, but with more colors.
Since John Tartaglia's abscence from Sesame Street, the duck has no permanent performer, and has been played by David Rudman and Tyler Bunch.

