Bert is the long-suffering best friend and roommate of Ernie.  He appeared with Ernie in the first episode of Sesame Street back in 1969.

Bert is more serious, focused, and practical than Ernie, and he considers himself the voice of reason in their friendship.  He has great patience and often helps Ernie by explaining something to him.  For example, when Ernie wasn't feeling special, Bert made him touch his nose explaining no one else had a nose like his or was like him and that he was, in fact, special.

Being rather unconventional, Bert collects bottle caps and paper clips, plays the tuba, and loves his pet pigeon, Bernice.  Bert taught Bernice how to play checkers with him, which she won two out of ten times.  He not only reads books about pigeons and watches them on Pigeons in teh News, but also attends conventions and parties devoted to pigeons.

Bert likes to do things on his own most of the time.  He is not usually a willing participant in Ernie's escapades.  He correctly senses when the tables are about to be turned on him.  But Bert always forgives Ernie, forever remaining his "old buddy."

Making his debut on a 2019 postage stamp is a rare instance where we see Bert and Ernie apart.  Both appear on a sheet of 16 stamps with other characters from Sesame Street in honor of its 50th anniversary.