NEW YORK -- Although most may not be aware of it, more and more tourists looking skyward to gawk at New York's landmark Empire State Building can occasionally catch a glimpse of a creature fast becoming another icon of the Empire State -- the peregrine falcon.
Those lucky enough to recognize the peregrine -- known to frequently perch atop the landmark -- can enjoy seeing the world's fastest animal at home in the nation's largest city. They are also witnessing evidence of the remarkable recovery of this bird of prey, which had earlier been almost entirely wiped out in the Northeast by the pesticide DDT.
Experts say the city is home to the largest population of urban peregrines on the planet, and the birds are fast becoming regular fixtures of Manhattan's artificial canyons. But greater contact with humans brings with it more threats and bird fatalities, a less-talked-about underside to this success story.
Ten years ago on this date, the peregrine falcon was removed from the U.S. endangered species list. Though peregrines are still a fairly rare sight in the Northeastern states, scientists say populations are abundant and healthy in the West and other parts of the world.
Experts say the national ban on DDT use -- the ingestion of which caused peregrine eggs to become too weak -- and the bird's steady recovery nationwide justified the delisting a decade ago.
The peregrine falcon remains on New York's own endangered species list, although the state is said to boast the largest population in the region. But conservation officials in Albany say they are close to downgrading the bird's status to threatened, as it's clear peregrine populations are growing fast with minimal human nurturing.
"The peregrine is doing well in New York state, not just New York City but statewide," said Barbara Loucks, an officer with the endangered species unit of the New York State Department of Environmental Conservation.
DEC says the state population has grown from just two pairs of nesting couples in 1983 to 67 total pairs in a 2008 study, with the numbers climbing steadily every year in between.
"I think this is going to be a good year also," Loucks said. "We had several new nests statewide and several new nests in New York City."
Nowhere is the bird's rebound more evident than in the Big Apple. Roughly a dozen couples make their home in Manhattan and the outer boroughs. Nests can be found on all the city's major bridges and on prominent local fixtures such as the MetLife Building, New York Presbyterian Hospital and Riverside Church. The population has even begun to spill over into New Jersey, with new arrivals nesting on bridges there.
"With 2008's production of 130 young hatched and 129 fledged, at least 1,444 young are known to have hatched and 1,403 presumed fledged in New York State since 1983," DEC said in its most recent report on the status of peregrines.
Those active in monitoring the bird's prognosis in the city and beyond say all signs point to a continued and rapid population expansion in the years to come. While DEC officials declined to give projections on how many birds will call the state and the city home in the decades to come, the peregrine's most optimistic supporters see a doubling or even tripling in the number of birds if conditions continue to improve.
"I don't think we've reached our carrying capacity for peregrines," said Glenn Phillips, executive director of the New York City Audubon Society. "I think we will probably have two or three times that number of birds in New York City alone in a decade or so."
Threats, old and new, remain
But Phillips notes that there is a downside to the fast recovery of peregrine falcons. Though cities make ideal habitats for the birds, with tall buildings mimicking their natural cliff-side perches and an abundance of pigeons and other urban wildlife to feast on, Audubon officials are concerned about the growing numbers of cases where peregrine nests are disturbed by building owners and maintenance crews.
"They are in close proximity to people, and so their nests are particularly vulnerable to human disturbance," said Phillips. "You could go down the list -- there are a million ways these sites can be disturbed, and it happens every year."
And in a sadly ironic twist, New York's newfound love for green buildings and eco-friendly architecture is increasing the threat to peregrines.
More peregrine falcons are getting killed from colliding into glass buildings, most recently when a tagged juvenile from Pennsylvania slammed into the Javits Convention Center on Manhattan's West Side. Phillips' group has noticed that more structures are maximizing window coverage to take advantage of daylight and reduce electricity bills. But the new windows lack a special material that reflects light in the ultraviolet spectrum, invisible to humans but visible to most birds.
DEC officials have also noticed an increase in peregrine falcon fatalities from accidents. Cars have struck young peregrines learning to fly on bridges. The birds have also been known to fly into power lines. And cases of peregrines nesting on apartment buildings have officials worried that residents attempting to use their balconies could get attacked by protective parents, inevitably causing the birds trouble.
But Loucks points out that many bridge operators are only too happy to have peregrines living on their structures because the falcons keep messy pigeons away, reducing the need for cleaning.
Aside from working with infrastructure and facility maintenance crews to schedule work away from nests or around migratory periods, and educating the public on how best to avoid disturbing nests and resting peregrines, state officials and conservationists say there is little they can do to keep peregrines from getting killed in accidents.
Audubon is advocating the production of bird-safe windows for use in all the green buildings going up around the city. But so long as peregrine falcons choose to make cities their home, they will face the risk of getting killed from car strikes or other trauma. Loucks says that's just the unfortunate reality behind the peregrine falcon's steady and strong recovery in the Northeast.
"It's not an abnormal environment for them," she said. "The peregrines will go where the food is, and there is a lot of bird food in the form of pigeons and other species in the cities."