On merit alone, I Am Big Bird: The Caroll Spinney Story is a profoundly moving documentary. But if you grew up with “Sesame Street” in the 70s and 80s, you may find yourself experiencing an extra, particularly overwhelming set of emotions. Through an endless amount of television, feature film, and home movie footage, the film evokes the feeling of time passing rapidly, slipping through our fingers as we watch its human subjects age. As they get older, so do we, courtesy of our memories pulling us through the period from when we first engaged with “Sesame Street” through the present day. And yet, like Big Bird, that feeling of love and nostalgia we have for the show will always be frozen in childhood, never aging a day no matter how long we’ve been on this Earth.

Caroll Spinney has been the man inside Big Bird since the debut of “Sesame Street” in 1969. A puppeteer who once had a role on “Bozo the Clown,” Spinney landed the part of the country bumpkin, 8-foot tall yellow bird after Jim Henson came to see his one-man puppet show. The show went horribly, but Henson liked Spinney’s creativity under pressure. “Sesame Street” was in its infancy at PBS, and Spinney was assigned Big Bird and his polar opposite, a grumpy orange Muppet named Oscar the Grouch. Soon after, Big Bird’s countrified personality became that of a 6-year old child, and though Oscar’s personality remained the same, he dyed himself a grungy shade of green.

The perpetual optimist, Big Bird has been used to convey deeply emotional topics to children over the years, from the death of beloved “Sesame Street” character Mr. Hooper in 1983 to a more recent series of shows on bullying. “He’s complicated,” Sonia Manzano (aka Maria) says, “in ways the other Muppets are not.” I Am Big Birdshows how Spinney’s rough childhood contributed to the well of youthful hurt and confusion he can immediately tap and vocally convey through the limited mobility of Big Bird’s face. “When Caroll speaks of something that hurt him,” his wife Debra says, “even if it were 50 years ago, it’s as if it were happening to him right now.”

Conversely, Oscar the Grouch is the antidote after a day of being sweet, innocent Big Bird. “Oscar is the other side of Caroll,” someone says as we see footage of Spinney uttering a bad word brought to you by the letter F. Jon Stone, the first writer and director of “Sesame Street,” states that Oscar was “the most negative character to appear on a children’s show. He’s what kids are told not to be.” His forbidden nature explains why he was my favorite “Sesame Street” character, and why he certainly wouldn’t have made the cut had the show premiered today. While Big Bird’s voice is a higher variation of Spinney’s own, he tells us that he got Oscar’s growl from the NYC cab driver who drove him to the studio on the day he auditioned.

I Am Big Bird offers a plethora of details about Big Bird, from how he is operated by Spinney (it’s more low-tech than you think) to the number of feathers on his person. We meet Matt Vogel, Spinney’s understudy and eventual replacement, whose last name means “bird” in German. There’s also a hilarious anecdote, told by Loretta Long and Bob McGrath (Susan and Bob on the show), regarding the perils of Big Bird using a wireless mic to project his voice at a live event. It begins with some X-rated trucker talk emanating from Big Bird and ends with what the 14,000 kids in the audience perceived as Bob murdering Big Bird. This anecdote is worth the price of admission alone, and you’ll never be able to listen to that 70s classic “Convoy” the same way again.

While I Am Big Bird has its share of light-hearted moments, much of it serves as an unflinchingly honest portrait of a performer whose work has touched millions of children. It navigates the highs and lows of Spinney’s life, stopping to show how those elements shaped his art. Colleagues like director (and former Cookie Monster) Frank Oz talk about how Spinney didn’t fit in with the other puppeteers at first, partially due to the isolation involved in playing Big Bird and Oscar. Spinney says that his mentor and friend, the late Henson, chose Spinney’s characters wisely. They fit the personality of the ostracized kid Spinney was, the kid who was perfectly fine doing things solo.

I Am Big Bird is also a love story between Spinney and his second wife, Debra. Debra lists all the celebrities she and Spinney have met (including a young Michael Jackson shown interacting with Oscar), holding out hope that she may one day meet Paul McCartney. The story goes that McCartney and his late wife, Linda, were so in love that they had only been separated one day in their entire marriage; the Spinneys are like that as well. “We always shoot footage of everything we did,” Debra says, “so we can revisit the memories.”  Much of that footage plays under narration by Spinney and others, creating the film’s drifting-through-time effect.

Mitt Romney makes an appearance late in the film to prove that, even in the age of that red tyrant, Elmo, Big Bird still has relevance. “I like Big Bird,” Romney famously said, “but I’m getting rid of funding for PBS.” “I knew he’d be sorry for that,” says Joan Ganz Cooney, the creator of Sesame Street’s production company, the Children’s Television Workshop. The social media firestorm, not to mention the endless supply of late-night jokes about firing Big Bird, may have contributed to Romney’s defeat. Big Bird appeared on “Saturday Night Live” to comment on Romney, drawing rapturous applause on a show that once showcased Henson’s darker material.

My only complaint about I Am Big Bird is how little time it devotes to Sesame Street Presents: Follow That Bird. In exchange, there’s a subplot about the 30th anniversary of “Big Bird In China,” the TV show that sent Big Bird and Barkley the Dog to China. This material contains a huge, tearjerking moment between the Spinneys and Lianzi Ouyang, the little girl who helps Big Bird on his Chinese quest. Their reunion ends the film on a beautiful note that will move even those who have never heard of “Sesame Street.”

With I Am Big Bird, directors Dave LaMattina and Chad N. Walker have created a great, lasting testament to a character so iconic he has a balloon in the Macy’s Thanksgiving Day Parade–and the 81-year old man who continues to play him. Bring Kleenex. You’ll need it.