Autumn is an occasion for rare splashes of color in the Big Apple, where the approaching winter is defined by dark wool coats and snow that quickly turns gray.
But this year, the turning leaves in Manhattan's Central Park have been overshadowed by a rare bird -- a brightly colored Mandarin duck, seen swimming among the park's more pedestrian bird population.
Found predominantly in east Asia and some parts of Europe, the bird's appearance in an American metropolis is a mystery.
"The zoos say it's not theirs," said Dan Tainow, an urban park ranger with the New York City Parks Department. "It's most likely a pet."
Tainow said the bird could be from as far afield as New Jersey or Long Island.
"It flies fine; it eats," Tainow added. "The mallards don't even seem to mind it. Our orders are to leave it alone as long as it can feed and fly."
Even from a distance, the Mandarin duck's appearance is striking, with blocks of deep green and blue feathers.
The wandering waterfowl was spotted last month swimming among the mallards at Central Park's duck pond at the southeast corner of the park.
He quickly became a social media phenomenon. Someone made the duck a Twitter account, and he has a popular hashtag. New York Magazine's dating column joked the Mandarin duck was "New York's most eligible bachelor."
And like most New Yorkers experiencing their first brush with fame, Manhattan's new It Bird has moved from the hustle and bustle of Midtown to tonier digs uptown.
On Friday, a few dozen birdwatchers huddled around Central Park's Turtle Pond, a more secluded spot just steps from the Metropolitan Museum of Art and the site of Shakespeare in the Park. They were hoping to catch a glimpse of the avian anomaly, who was now camped out in the rushes below Belvedere Castle.
Bruno Boni De Oliveira, 31, stood at the edge of the pond beside a tripod supporting a massive telephoto lens. De Oliveira said he'd been following the Manhattan Bird Alert Twitter feed while out of the country on a business trip. He'd landed that morning, stopped at home just long enough to grab his camera gear, and came to catch a glimpse of the duck.
Mike Ritchey, 70, peered through a pair of binoculars as the duck stood preening himself on the far shore of the Turtle Pond.
"It's a fun bird," he said with a smile. "It's colorful."
Kate Lockwood, 44, stood on a bench nearby, scanning the shore.
"As a birder, there's always the thrill of the chase," she said.
For his part, the Mandarin stuck to the far side of the pond, ducking the attention and the telephoto lenses.
Back at the park's southern pond, where the Mandarin duck was first spotted in October, a gray-haired man approached a woman identifying birds with the help of her iPhone.
"Have you seen the Mandarin this morning?" he asked her.
"He's over by the Turtle Pond today," she replied.
"Oh," the man said simply. "Good for him."