Credit George Etheredge/The New York Times
Three years ago, as Lawrence Pugliares searched for bugs and butterflies to photograph within the Mount Loretto Unique Area, a 200-acre grassland along the south shore of Staten Island, something not so tiny soared over his head. Mr. Pugliares scrambled as an adult male bald eagle canvassed what would become its new home.
“I had to change lenses and, of course, I missed him,” said Mr. Pugliares, 52, a stenography instructor who has taken thousands of photos of eagles. “But we met again and again and again.”
Once considered rare, bald eagles have become increasingly common along New York City’s waterways over the last few years. Seven to 10 of the birds are thought to live on Staten Island, including two adult eagles frequently found at several coastal parks in three neighborhoods.
Recently, a younger bird has been seen consistently with the two adults, leading many to believe that Staten Island’s bald eagles have achieved a milestone this summer.
If the juvenile bird hatched in that borough, it would represent the first bald eagle born in the city in more than 100 years, according to the New York City Audubon.
Birders say the juvenile’s behavior suggests it was born to that pair of adult eagles. Thick-billed but not yet white-headed, the young bird has been photographed taking food from the beaks of the older birds, something that is considered a sign of successful breeding.
“This behavior certainly indicates that it is a young bird that hatched recently,” Debra Kriensky, a biologist with the Audubon group, said. “It’s very exciting.”
Mike Shanley, a birder on Staten Island and the president of the Friends of Blue Heron Park, said the feeding suggests “probable nesting,” meaning two adult birds building a nest to try to have offspring. It is “not confirmed breeding,” he added, “though it is a very good indicator.’’
Last year, two eagles tried but failed to breed near Mount Loretto. None of the bald eagles are banded or tagged, which makes tracking them a challenge. But the male spotted this year is believed to be the same male from last year and the same one Mr. Pugliares first encountered in 2013.
Officials at the state’s Department of Environmental Conservation, which administers the Mount Loretto area, expressed some skepticism that an eagle could have been born on Staten Island, noting that the birds could have wandered across Raritan Bay from nesting sites in New Jersey. Without a confirmed nest, there is no way to be certain where the eagle was born.
Credit George Etheredge/The New York Times
But birders say there are plenty of remote places on Staten Island where a nest could be hidden.
“There are a lot of thick woods,” Mr. Shanley said. “If they nested in the top of a tall tree in the middle of those, nobody would have found them.”
It is not uncommon for eagles to fail to breed — meaning a nest was built and eggs were laid but did not hatch — several times, said Ed Johnson, the former director of science at the Staten Island Museum. “They need a few tries to get it right,” he said.
There is mounting circumstantial evidence that they did so this year: The adult birds and the juvenile, which is at most a few months old, have been spotted perching on the same branch, communicating and feeding together, implying that the young bird hatched in the area.
What is undeniable is New York’s place among urban areas to which eagles, once threatened with extinction, have returned.
Widespread pesticide use after World War II had decimated their numbers. “In 1960, there was only one breeding pair in all of New York State,” Ms. Kriensky said. But after decades of federal protection, the birds were removed from the endangered species list in 2007.
Bald eagles have also become regulars in Flushing Meadows-Corona Park in Queens and along the Hudson River in the Bronx and Manhattan.
“The way I grew up,” Mr. Pugliares said, “we knew about the national bird but we never saw it. Now they’re here. I mean, they’re right here.”
Since 2009, over 900 eagle sightings on Staten Island have been reported on eBird.com, a website that tracks bird sightings and population trends. Most have been of the adult male that Mr. Pugliares has seen so often that he gave it a nickname: Vito, after the patriarch in “The Godfather.” The eagle often flies over a church where parts of the movie were filmed, and perches conspicuously on telephone poles throughout his sliver of territory.
Since his arrival, Vito has been the most popular attraction on a Facebook group page devoted to Staten Island wildlife — a “rock-star bird,” as Mr. Pugliares says.
The juvenile bird was easily spotted recently at one of Mount Loretto’s ponds. Mr. Pugliares took photos as it spread its wings, exposing its brown belly, to bask in the sun for several minutes. It certainly appeared at home.
“I’ve never seen any eagle act this way,” Mr. Pugliares said.
But the nest where the eagle was born still eludes him, as it does everyone else.
“It’s hard to say exactly what happened with the nest,” Ms. Kriensky said. “The fact that they are here in general is pretty amazing and a sign that these birds are thriving.”