NEW YORK — On the street, Caroll Spinney is a 74-year-old of modest proportions. On the job, transformed into Big Bird, he stands 8 feet 2 inches tall and is 6 years old.

Being Big Bird is sweaty, physical work. But Spinney, who has worked on "Sesame Street" for nearly four decades playing both Big Bird and Oscar the Grouch, has no wish to be anywhere else.

"I can't imagine willingly walking away from Big Bird and Oscar," he said.

Spinney's workday transformation begins with a pair of orange furry jeans encircled in hot pink ridges. Next, manhole-size pink webbed feet made of foam — built around a pair of Hush Puppies loafers. Between takes, he protects them from his kindergarten co-stars with custom-made purple slippers.

The crew straps a television monitor to his chest. Wearing drugstore reading glasses, Spinney will watch the monitor while inside the top half of the costume to see how Big Bird appears on camera. Otherwise, he's blind inside the bird.

To play the role, "you have to not be claustrophobic," he said. "You have to be willing to walk, not seeing anything in front of you."

Spinney tops off his ensemble with the familiar 25-pound top half of Big Bird, a combination of costume and puppet. He works Big Bird's mouth with his hand and the eyes with a coat hanger attached to his pinky finger.

The set is kept so cold for his scenes that the crew sometimes wears hats and jackets. For Spinney, who called out from his perch on the stoop of 123 Sesame Place that he could no longer feel his hands, the relationship between man and bird is worth it.

He remembers a visit to Georgia Tech in 1972, when the costume was "ravaged" by ROTC students. When he found Big Bird, one of the eyes was hanging off, its mechanism ruined.

"When I saw him lying in the dirt, it was like seeing your child dead on the floor," Spinney said. "I went into shock."

Spinney got his start on "Sesame Street" during its first season in 1969, after Muppets founder Jim Henson saw him perform at a puppeteer's convention.

Henson chose him as Big Bird after Frank Oz, who helped develop Bert, Grover and Cookie Monster, swore off costume puppets following a stint in commercials as the La Choy Dragon, which was equipped with an in-costume flame-thrower.

Spinney met his wife, Debra, at Sesame Workshop, and has three children and four grandchildren. He's one of a handful of original cast members still on the show; the other original puppeteer still working full time is Jerry Nelson, who plays The Count.

"One of the things I really enjoy about 'Sesame Street' is that years go by and I'm still the same age," Spinney said. "I'd love to be 70 again, 60 and 50 and 40."

After all these years, "Sesame Street" remains seasonless. There are crunchy autumn leaves at the stoop of 123 Sesame Place, because the set looks flat without them, but the garden around the corner is in full summer bloom. Since no brands are allowed on the show, the shelves of Hooper's Store are stocked with Sesame-ized magazines, like "City Monsters: Puffy Furry Fun for All Ages!" and "Stacking Stones."

"We deal with a lot of life's realities on 'Sesame Street,' but not everything," Spinney said. "No one worries about him (Big Bird) sleeping all alone on the street."

While the show takes place in a magical mirror New York, the set is at the Kaufman Astoria Studios in Queens, where decidedly grittier fare such as "Fort Apache-The Bronx" was also filmed.

On the last day of filming this spring, the Big Bird head was wheeled upright on a dolly as Spinney sat on the stoop. "Bird on the move!" shouted senior muppet wrangler Michelle Hickey, pushing it up a ramp.

She pulled the bird off the dolly and put a hand in Big Bird's slack mouth as Spinney, sitting on the stoop, held up his right arm to put it on. As Big Bird's face came to life, another puppeteer, hiding behind a pile of books, acted as Spinney's right-hand man, working Big Bird's right arm as well as a monofilament controlling the left arm.

A question came from the crew: "How's the kid placement?" It was fine.

"And the count is to Big Bird," the floor manager said. The scene began with Big Bird asking two children whether they'd like to hear a story.

When Big Bird and Oscar appear in the same scene, Spinney pre-records Oscar's voice, then acts the scene as Big Bird while someone else puppeteers Oscar.

Spinney says he modeled Oscar on the Bronx taxi driver who drove him to the old Muppet Mansion the first day he played the character, greeting him with a gruff, "Where to, Mac?" In Spinney's mind, Oscar is 43.

When the Big Bird costume is not in use, it's stored in a crate about 10 feet high. A muppet wrangler smooths Big Bird's feathers when they get ruffled and hand-glues replacements if they get crunched.

The feathers arrive from supplier American Plume & Fancy Feather Co. in New York's garment district on boas, dyed two colors of yellow. The muppet wranglers grade them, A through D. Only A and B-plus feathers are applied to Big Bird's head and neck.

"I'm still using the head we started with," Spinney said. "He's had face lifts." He estimates Big Bird has been through four bodies. Oscar still has his original eyebrows.

A muppet wrangler also travels with Big Bird when he's on the road. The body of the costume is shipped in two crates; the head travels in a separate box.

"My worst fear is that we take off and I would see the boxes lying on the tarmac," Hickey said.

After seven years of working with Spinney, Hickey described him as having "the heart of Big Bird and a teeny bit of Oscar."

Elizabeth Fernandez, 20, started working at "Sesame Street" as an intern in the research department and is now an assistant talent coordinator, working with the children who appear on the show, while she finishes college at night.

"People here are so encouraging about going to school, getting your master's degree," she said. "There's room to move up; a lot of people started as interns.

"It really is 'Sesame Street.' "