NEW YORK – Uno the beagle turned Madison Square Garden into his own big, green backyard.

He barked and bayed. He nipped at a newly printed sign. He tried to grab his leash. He took a flying leap at a piece of filet mignon.

“Snoopy would be proud,” handler Aaron Wilkerson said Monday. “He was being his merry little hound self.”

He also did something out of character: He became the first beagle to win the hound group at the Westminster Kennel Club show since 1939 – that’s 483 years, in dog years.

America’s top dog competition has presented best in show 100 times and a beagle has never won. Uno’s victory assured him a place in the final seven Tuesday night.

Beagles are always among the most popular dogs in the country, yet Wilkerson was at a loss to explain why they’ve never done better here.

“I can’t really say,” he said. “All of them are just good.”

A repeat standard poodle, a prize-winning Sealyham terrier and an Australian shepherd also locked up spots in the final ring. A perfectly trimmed toy poodle and a top Akita hoped to win their groups Tuesday.

They were among the 2,627 entries at this year’s show, coming in 169 breeds and varieties. Included were four newly sanctioned types – the Tibetan mastiff, Beauceron, Swedish vallhund and Plott.

Also in the building: Patty Hearst and “How to Look Good Naked” reality show host Carson Kressley.

Far, far removed from the days when her image as a machine gun-toting revolutionary captivated a nation, Patricia Hearst Shaw was in more genteel surroundings. She was tending to Diva, petting her French bulldog’s soft head on dogdom’s biggest day.

“When people find out it’s me, it’s like it doesn’t make sense,” Shaw said. “The Frenchie people know me because I’ve been around. But others, they seemed surprised.”

Shaw has been working with dogs for three years, and her first trip to Westminster was well worth it. She came away with a red ribbon for Best of Opposite Sex – a male won the breed, and hers was judged the top female.

“It’s overwhelming,” she said.

Kressley, who formerly starred on “Queer Eye For The Straight Guy,” had his hair “zhooshed” just like the dogs. He found himself looking at more than the pooches.

“I was mesmerized by the handlers’ outfits,” he said. “And they have to wear sensible shoes.”

While Uno aimed at best in show, the precocious package of personality certainly deserved one title: noisiest in show.

“Ah-rooo!” his howls echoed all over the arena. It didn’t take much to get Uno going, either. A click of a spectator’s pen, a wave of the judge’s hand, any effort by Wilkerson to hush him. “Ah-rooo!”

Though the Disney movie “Underdog” was a big winner last year, a beagle is forever a long shot at the Garden.

Tri-colored and nearly 3, with pleading, golden-brown eyes and a most playful nature, Uno wanted to break out of the Westminster doghouse. His official name is K-Run’s Park Me in First, and he topped 12 other entries in the 15-inch beagle category.

Beagles also come in the 13-inch variety, though both types can come from the same litter.

Uno already has won 32 best in show titles and finished 2007 as the sixth-ranked show dog in the nation. He retreated to the safety of his crate after winning best of breed, complete with his favorite stuffed frog toy and a fluffy pillow sporting a Hollywood star.

Judge Ralph Lemcke picked Uno over 25 others in the hound group, praising his “soft expression” and the neat “brush on his tail.”

In December, Uno won the hound group at the big AKC/Eukanuba show in Long Beach, Calif. The winner of that event, a Sealyham called Charmin, won the terrier group.

Charmin is “squeezably, wonderfully soft,” co-owner and handler Margery Good said. He has a dark gray patch over his left eye and a tremendous pedigree – his brother is the top-winning dog in Canada.

A standard poodle with white pompoms on his feet and tail won the nonsporting group for the second straight year. Merci was a clear pick for judge Michael Manning.

“Beautiful is beautiful,” he said. “His personality went on for miles.”

Deuce, a 4-year-old Australian shepherd, won the herding group. She took a year off to have nine puppies and returned to the show ring last month.

Judge Stanley Saltzman said Deuce never missed a step, complimenting how she had “a lot of reach and drive in her stride.”