“See that!” he added, spotting a somersault. “I love them.”

Mr. Sampson was first seized with a passion for pigeons as a 10-year-old immigrant when he saw the Walt Disney movie “The Pigeon That Worked a Miracle.” A few years later, he fell under the influence of Joe LaRocca, the president of a pigeon racing club. After Mr. Sampson learned the basics of raising pigeons, Mr. LaRocca and a colleague talked to his mother about his new hobby.

“They gave her the lesser of two evils,” he said. “I could hang out on the street and the street would claim me, or I could be hanging out on the roof with an interest in pigeons.”

A half-century later, Mr. Sampson still breeds his own birds, which come in myriad varieties and look different from feral pigeons that haunt the city’s squares and parks. In shops, pigeons typically cost $5 to $40 apiece, though sires of champion racers can cost six figures.

Like most breeders, Mr. Sampson spends hours each day scraping away bird droppings, hosing down coops, stocking feeders, filling water canisters and hauling 50-pound bags of feed up a 10-foot ladder and through a hatch to the roof. He uses a syringe to vaccinate each of his 300 birds against diseases and keeps a large rooftop medicine chest stocked with antibiotics, herbs, bath salts, treatments for lice and mites, and even Vicks Formula 44 for colds.

“I relate to the birds as if they’re like me,” he said. “If I’m sick, they’re sick. If I’m cold, they’re cold.”

He spends so much time on the roof, he has built himself a shack, outfitted with a heater, a television and a bunk bed for napping. Pigeon flying is often turned into a competitive game, with rivals sending their flocks into the sky to mix with other flocks, with the goal of luring the other pigeons into their own coops. Some breeders also race pigeons.

One thing all fliers lament is that younger people are not taking up the hobby. In the 1950s, every other low-rise roof in certain neighborhoods seemed to have a pigeon coop. But fewer people showed interest in the sport, and landlords also cracked down because gentrifiers did not like the pigeon mess. Dr. Jerolmack estimates there are no more than 300 pigeon fliers left in the city.