[This is especially for Martin.]
The peregrine falcon, whose salvation began 40 years ago, commands the skies
above the Empire State Building
a.. By Meera Subramanian
b.. Smithsonian.com, December 10, 2009
I'm standing a thousand feet above the streets of New York City, on the 86th
floor observatory deck of the Empire State Building, looking for birds. It's a
few hours after sunset, and New York City naturalist Robert "Birding Bob"
DeCandido is leading our small group. We can see the cityscape in every
direction as the cool wind tousles our hair, but our gaze is focused up.
Migrating songbirds, many of which travel by night to keep cool and avoid
predators, are passing high overhead on their autumn journey. DeCandido has
taught us how to differentiate the movement of small birds-"See how they
flap-flap-glide?" he tells us-from the erratic motions of moths, But there is
another denizen of the city's skies that we're all hoping to see.
A blur of a bird zips past the western flank of the building, level with the
observatory. It's too fast for a gull, too big for a songbird. Maybe a pigeon.
Maybe something else. There is an excited buzz as we fumble with binoculars,
unable to track the receding figure.
Ten minutes after that first flash, an unmistakable form draws our eyes
directly overhead. Collectively, we cry, "Peregrine!" The falcon is smaller
than the red-tailed hawks that live in Central Park, and sleeker, with a long,
narrow tail that flares as the bird turns and sharp, pointed wings that propel
its body fiercely. It loops around the building, in complete control as it
navigates the blustery night air, its undersides transformed into a ghostly
white by the upward shine of the building's glaring spotlights. It closes in on
a potential perch midway up the spire and then suddenly veers south and
disappears into the night.
"Come back," someone whispers plaintively.
"Show me the top of the food chain," says another.
*
There is a reason fighter jets and football teams are named after falcons. At
their standard cruising speed of 40 miles per hour, peregrines are apace with
pigeons and many other birds that are the basis for their diet, but falcons can
go into overdrive in an aerial feat known as a stoop. They rise dozens of feet
above their prey, tuck their wings in tightly against their bodies, and dive -
a furious, feathered mission. The fastest animal on earth, they have been
clocked at over 200 miles per hour as they descend upon their target, balling
up their talons to stun their prey and then - supremely agile, able to turn
upside down with a quick flip of the wing - scooping up their meal.
Forty years ago, we couldn't have seen a peregrine falcon from atop the Empire
State Building, or anywhere else on the entire East Coast. They were nearly
obliterated in the middle of the 20th century by the effects of the pesticide
DDT. Seed-eating songbirds fed on treated crops and were in turn eaten by the
avian predators hovering at the top of the ecological pyramid. The pesticide
didn't kill adult falcons, but it concentrated in their tissues and interfered
with females' ability to produce strong eggshells. Brooding peregrines,
settling down upon their clutches to keep them warm, were crushing their
progeny with the weight of their bodies. In 1962, Rachel Carson's Silent Spring
was published, warning of the unintended consequences of our new chemical age.
By 1964, not a single peregrine falcon was found east of the Mississippi River.
In 1970, an improbable team of scientists and falconers that became known as
the Peregrine Fund banded together at Cornell University in upstate New York to
bring back the birds. Under the guidance of ornithologist Tom Cade, they
planned to breed the birds in captivity and then release them into the wild
after DDT had been banned, which it was in 1972. Because so few of the native
falcons were left in the wild in the continental United States, they gathered
peregrine falcons from around the globe, creating an avian immigrant story.
They used the few members they could find of the subspecies that had dominated
the United States, Falco peregrinus anatum, but added a handful of other
birds-of the F. p. pealei subspecies from British Columbia and peregrinus from
Scotland, brookei from Spain and cassini from Chile, tundrius from arctic
Alaska and macropus from the southern reaches of Australia. While some people
objected to the mixing of lineages, the scientists knew their options were
limited. They also made the argument that hybridization could actually be a
boon to a species that was facing a genetic bottleneck if they survived at all.
"A peregrine is a peregrine," Cade told me. Give the new generation of
peregrines all the world's genes, the logic went, and at least some of the
birds will be fit to replace America's lost peregrines-to traverse the fields
of this region, live off the bounty of its airborne harvest, nest along its
rocky cliffs.
The Peregrine Fund started with a small team of staff and volunteers who
skirted building codes as they lived illegally in the peregrine breeding barn,
cooking on a two-burner hot plate and bathing with a garden hose through
upstate New York winters - anything to be with the birds 24/7 during the
tenuous process of raising the vulnerable chicks. Using both natural and
artificial insemination, breeding began in 1971, and just two years later, the
Peregrine Fund newsletter announced a "bumper year."
"In 1973, we raised 21 young from three fertile pairs," Cade told me. "That
clinched it in our minds that we could do this. We'd need dozens of falcons,
but not hundreds." With 30 breeding pairs, they could repopulate the eastern
United States. Starting in 1974, the Fund began to release fledgling birds in
prime peregrine habitat, wild places from New York's Adirondack Mountains to
Maine's Acadia National Park.
Then the birds reappeared, against all expectation, in the largest city around.
A peregrine released in New Hampshire in 1981 showed up on the Throgs Neck
Bridge in New York City two years later, the beginning of the abundance we see
today. Over the course of nearly two decades, more than 3,000 young peregrines
were released across the United States. Thousands of pairs are now breeding in
the wild in North America, and the birds were taken off the federal endangered
species list in 1999, although they remain listed in New York State, where 160
birds were released. Something shifted upon their return. Their old cliffside
nesting sites along the Hudson River Valley and elsewhere still existed, but
many falcons chose the city instead. Immigrant birds had come to the city of
immigrants.
>From the observation platform, we continue to watch songbirds pass high above
>us as crowds of tourists maneuver slowly along the perimeter, taking
>photographs and pointing, speaking in French, Japanese, Italian and other
>tongues. Some pause by our group, eavesdropping, as DeCandido points to where
>peregrines have come to nest in the city-on the nearby MetLife building, the
>New York Hospital, the Riverside Church, the George Washington Bridge, the
>Brooklyn Bridge and the 55 Water Street building. They nest 693 feet up the
>distant Verrazano-Narrows Bridge that's lit up in a twinkling string of green
>sparkles and have taken over an osprey nest in the darkness of Jamaica Bay.
At least 17 breeding pairs live within the borders of the five boroughs, the
densest known population of urban peregrines in the world. The new generation
adapted to the concrete canyons, towering bridge supports and steel skyscrapers
of Gotham, redefining falcon habitat. It was as though we had built them a new
world, with perfect nest sites-high, adjacent to wide expanses of open flyways
for hunting and populated with an endless, year-round food source in the form
of pigeons, another cliff-dwelling bird that finds our urban environment so
pleasing. A biologist from the New York City Department of Environmental
Protection makes annual rounds to the peregrine sites, banding young and
building sheltering boxes wherever they have chosen to nest.
The Empire State Building granted peregrines the additional gift of a nighttime
hunting perch, smack in the middle of one of North America's busiest bird
migration routes. The building's lights were the brightest continuous source of
artificial light in the world when they were installed in 1956. Today, the
illumination makes it easy for peregrines to spot their migrating prey. It's
happening elsewhere. Peregrine falcons have been observed hunting at night in
England and France, Berlin, Warsaw and Hong Kong, and off brightly lit oil rigs
in the Gulf of Mexico. Many bird populations are plummeting because of habitat
loss and other environmental threats, but peregrine falcons are thriving,
brought back from the brink, returned, reintroduced and reimagined back into
existence through science and passion.
*
DeCandido didn't start coming to the Empire State Building in search of
falcons, though. He came to count songbirds-dead ones. Generally, birds get the
sky and we get the earth, but sometimes there's a mix-up, and the two
territories overlap. One morning in 1948, 750 lifeless birds were found at the
base of the Empire State Building. "Mist Bewilders Migrators. Tiny Bodies
Litter 5th Avenue," announced The New York Times.
That was a record night, but every day, dead birds are found at the base of
buildings. A recent study by New York City Audubon estimated that 80,000 birds
perish each year in the five boroughs because of collisions with buildings.
Ornithologist Daniel Klem of Muhlenberg College, who has studied bird
collisions for more than 20 years, estimates that hundreds of millions of birds
die each year from striking glass windows-more avian deaths than are caused by
cats, cars and power lines combined. Compared with building strikes, peregrines
and other avian predators barely make a dent in overall songbird populations.
DeCandido first went to the Empire State Building in the fall of 2004, prepared
to witness migrants crashing into windows. Instead, over 77 nights, he and his
team of volunteers found only four dead birds and discovered a miraculous New
York nighttime bird-watching site. They checked off 10,000 birds on their
clipboards that fall-Baltimore orioles and gray catbirds and black-throated
blue warblers. Chimney swifts and common nighthawks. Great egrets and night
herons. Gulls and geese. A saw-whet owl and a short-eared owl. And other flying
creatures, such as little brown bats and red bats, snatching moths and
dragonflies. On more than half of the nights, they were accompanied by a
peregrine falcon, hunting by the bright lights of the big city.
DeCandido's work confirmed what Klem, the Audubon researchers and others were
finding-that most bird fatalities happen at the lower levels of structures,
especially when glass reflects landscaping and creates the lethal illusion of a
resting spot. Landscape architects are beginning to take placement of
ornamental plants into consideration to minimize this deception while design
firms continue to develop a type of glass that looks to a bird, in one
architect's words, "as solid as stone."
*
Fifteen minutes after our first sighting, the falcon returns to lie in wait on
the northern side of the spire, with a clear view of incoming bird traffic. A
few minutes later, a small form approaches with the flap-flap-glide movement of
a songbird. As it appears within our halo of light, the falcon charges from its
station, circling wide and then closing in fast on the unsuspecting creature.
The peregrine comes down hard on the bird, which drops straight down as though
injured, but the falcon swerves off, talons empty, returning to another perch
overhead. The smaller bird, DeCandido explains, folded its wings and dropped to
escape.
The falcon has speed, but this alone doesn't secure dinner. Persistence is a
requirement as well. Every few minutes, the falcon launches itself after a
weary migrant, but each time, the hunter misses its quarry. Then DeCandido
declares a faraway, lit-up speck to be an approaching rose-breasted grosbeak.
The small bird veers east as the peregrine rises, for the sixth time, both
disappearing behind the spire. We lose sight of them on the far side, gauging
their speed and waiting for them to emerge on the other side of the tower. They
don't. Just the falcon appears, landing briefly back on its perch. "Did he get
it?" someone asks, necks straining, eyes glued to binoculars in a hard squint.
And then the falcon lifts off, and we can see the limp bird held tightly in its
grasp as it drops down to the northwest, toward the Riverside Church perhaps,
wings arched, gliding down to some favorite plucking post to eat.
The peregrines have returned. To North America, and-unexpectedly-to many of the
cityscapes of the world. When it comes to bird habitat, humans have destroyed
more than we have created, but for the falcons we have inadvertently made a
nice home. Songbirds pass overhead as the night goes on, but the small beings
can no longer hold our attention. It's not even 9 p.m., early for us city folk,
so we return to the sidewalk realm of humans and down farther into the subway
tunnels below, leaving the secret avian superhighway above to carry on its
mysterious motions of life and death, the top of the food chain that has
returned, reigning over all.
Read more:
http://www.smithsonianmag.com/science-nature/The-Worlds-Fastest-Animal-Takes-New-York.html?utm_source=sciencenewsletter1216&utm_medium=email&utm_campaign=MonthlyScience#ixzz0a00Z0NVv
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