City birds learn to fly

Danielle Genter was rushing down Summer Street to retrieve a fledgling peregrine falcon that was grounded in a loading dock when she heard herring gulls overhead, harassing another raptor attempting its first flight.

"I looked up and saw him hit the side of the building," said Genter, a rescue specialist with the Animal Rescue League of Boston. "He pretty much smacked into the window on the side."

Such is the challenge of growing up in the city for a bird that nests high atop structures including the First Church of Christ, Scientist administration building, and the Goliath crane in Quincy Shipyard. But despite last week's clumsy attempts at first flight -- which the fledglings are believed to have survived -- the birds' visibility on the Boston skyline is testament to the strength of a species that has fought its way back from the brink of extinction. Massachusetts, which still lists the falcons as endangered, tallied 25 chicks this year, the highest number in decades.

"Peregrines are here to stay," said Tom French, assistant director of MassWildlife's Natural Heritage and Endangered Species Program. "They're part of the city environment now and many an office worker tells me they see them whizzing by their windows."

Since May, French has counted 11 pairs of the monogamous peregrine statewide. Though there are no current plans to take them off the state's endangered species list -- and they still have not reached the historic numbers of 15 nesting pairs -- the numbers are encouraging.

"I think they're going to be back where they were historically in the next five years," said French.

Nationally, the re-emergence of the peregrines is one of the shining success stories of the Endangered Species Act. The falcons' numbers dwindled due to the pesticide DDT, which was thinning the shells of the birds' eggs, causing them to break during incubation. The birds were listed as endangered nationally in 1970, and by the mid-1970s, were gone from the eastern United States. Their population had plummeted to 324 nesting pairs in all of North America.

Their long, slow comeback followed a government ban on DDT in 1972, and government and private recovery efforts aimed at releasing captive-born falcons into the wild to breed. The US Fish and Wildlife Service, which took them off the federal endangered list in 1999, reported last year that there are more than 2,000 breeding pairs across the country.

"They're a prime example of what can happen when the environment is taken care of," said Massachusetts Audubon Society spokesman John Gibbons.

Peregrine falcons nest on ledges and in shallow caves high on cliff walls, using almost no materials to build their nests. As such, they have taken naturally to the sparse verticality of urban living.

Wildlife specialists believe the peregrines who occupied an old nest box on the Tobin Bridge may have relocated to the control tower at Logan International Airport. A new pair popped up on an abandoned mill building behind the Paul E. Tsongas Arena in Lowell. And when the Custom House Tower this year evicted a nest box used since 1986, a pair of peregrines found swank new accommodations at the Federal Reserve Bank of Boston -- on a garden balcony with waterfront views outside the office of the president.

When the raptors began to leave their nests last week, they caused some consternation among downtown workers. Attorney John Sutter called animal rescue workers on Monday, fearing that the young falcon perched on an unusually low fifth story ledge near his Federal Street office was injured.

"It was being mobbed by seagulls and it wasn't flying away," he said. "I know that they are a threatened animal and I was concerned."

Genter said that the falcon was not hurt, but she and other specialists intervened last week to help several others faltering in early attempts at flight, returning them to higher rooftops.

The fledglings first take off at about seven weeks old, resting on rooftops and ledges -- and, occasionally, parachuting to the ground in a controlled descent. It takes just one to three days for them to gain their confidence and learn to soar majestically over the skyline. Ultimately, they are capable of remarkable speeds: The world's fastest birds in flight, they can zoom at more than 200 miles an hour when diving for prey including starlings and pigeons.

In some ways, their urban habitat may even protect the young, French said. They have friends calling for help when they're in trouble.

"Out in nature," French said, "they get out on the ground, they're lunch."

Stephanie Ebbert can be reached at ebbert@globe.com.