The 88 spotlights had been turned on since late afternoon, but it was only as dusk fell that their beams became visible. Wan and informal at first, their lights grew steadily brighter as the evening grew darker. The spotlights were aimed skywards and set up inside a fenced-in lot in lower Manhattan’s Battery Park City, divided up between two raised platforms and arranged into two squares. They remained lit from dusk on September 11 until dawn the next day, their beams combining to form two phantom pillars of pale blue—ethereal echoes of the World Trade Center towers that once stood nearby and a tribute in light to the victims who died when those towers fell.
Seen from a distance, the columns appeared to sparkle as light was being reflected off of small objects moving swiftly in the beams. The effect was beautiful but unintentional. The tribute designers never planned for it and no such sparkling was seen the first few times the memorial was lit.
When the effect began appearing in 2004, people didn’t quite know what to make of it. Some thought that dust or ash had inadvertently become illuminated, like floating dust in a shaft of light. Others thought that maybe fireworks had been set off and that distance was muting the sounds of their explosions.
Rebekah Creshkoff was in Battery Park that evening, close enough to the tribute to know that none of these guesses were correct. Gazing up, she didn’t see dust or ash or fireworks, but wings. Thousands of wings. Wings from birds and bats and moths that were flying in and circling the beams. Flapping and flitting and fluttering, the wings reflected and scattered and dispersed the tribute’s light, making the pale spectral beams sparkle.
The first thirty feet above the beams were packed with moths that had become drawn to the lights. On the platforms where the spotlights were arranged, Creshkoff saw technicians wearing dark sunglasses walk from one to another and using cloth rags to wipe off the blackened husks of those that had strayed too close to the 7,000-watt lamps.
Creshkoff is the founder of New York City Audubon’s Project Safe Flight, an organization that has been monitoring bird causalities in the city since 1997. During the spring and fall when birds migrate, volunteers patrol the perimeter of skyscrapers in Manhattan’s midtown district, collecting and cataloguing dead and injured birds, casualties of either mid-air collisions—with the sides of glass buildings or with each other—or from exhaustion after circling repeatedly around especially bright lights.
Gazing up at the Tribute, Creshkoff worried that a similar end might await some of the birds wheeling overhead.
“Sometimes they would break free so you could see them exiting the light and then they’d come back into the shaft of light,” Creshkoff remembered. “They would do that repeatedly—break free from one beam and get sucked into another one.”
Creshkoff remembers looking up at the birds and feeling sick. “It was really distressing to someone who has been following this problem like I have,” she said.
Creshkoff didn’t linger long at the tribute. After about half an hour, unable to bear the birds in distress any longer, she headed home.
Creshkoff had witnessed the same thing happen last year. Shortly after that first experience, she came up with an idea that she thought might help the birds. She proposed that the city end the memorial at midnight—before bird migration traffic reached its peak—and having the 88 spotlights be turn off one at a time, rather than all of them simultaneously at dawn. According to the plan, the lights would begin dimming around 10:30 pm and then gradually fade out until the last light was turned off at midnight. The plan seemed like a win-win situation: the birds would be spared a major distraction during their migrations and the city would have a beautiful and fitting end to its memorial.
When Creshkoff met New York City’s Municipal Art Society to discuss the proposal, however, she was kindly told that the plan would never work. The problem, of course, was money—not that there wasn’t enough, but that too much had been invested.
“I thought it was a wonderful idea but a lot of people contributed a lot of money to buy these lights,” Creshkoff said. “They get to use them only once a year. They’re not going to want to see them go out early.”
While Creshkoff was watching the birds from the ground that night, Andrew Farnsworth, a graduate student at Cornell University’s Ecology and Evolutionary Biology Department, was observing the same spectacle from atop a nearby thirty-eight-story building.
Farnsworth had been hired by Audubon to monitor bird activity around the tribute while it was lit. Concerned about the effects the lights might have on migrating birds, Audubon had made a deal with the city: if observers like Farnsworth witnessed at least 5 birds being killed or injured as a result of the lights, the city would shut down the tribute for 20 minutes to allow the birds time to disperse.
An avid birder since he was four-and-a-half years old, Farnsworth has spent many nights awake just watching and listening to migrating birds’ nevertheless, the tribute stakeout was a unique experience for him.
Farnsworth was accompanied by his fiancé, and the two of them camped out on the roof of the building from before sunset on Sept. 11 to sunrise the next day.
“We spent the whole night on top of the building,” Farnsworth said. “Our monitoring consisted of 3-5 minute periods watching the birds in the beam, followed by the same time period watching the general procession of migration in and around the beams.”
Over the course of the night, Farnsworth recorded the presence of a wide variety of birds.
“Small songbirds were by far the most common in the beam, especially warblers,” Farnsworth remembered.
That night, Farnsworth also recorded the presence of 7 veerys, 6 yellow-billed cuckoos, 4 scarlet tanagers, 4 rose-breasted grosbeaks, 3 gray catbirds, 3 indigo buntings, 2 wood thrushes, 1 sora, and 1 American robin; there were also herring gulls, sparrows, northern waterthrushes, yellowthroats and redstarts.
Whenever possible, Farnsworth identified the birds based on their size and plumage color through the use of binoculars and a spotting scope. But sometimes the swirl of birds became too chaotic and visual identification became impossible. When that happened, the birds were identified based on the distinctive sounds each species made. Using a shotgun microphone and a digital audio recorder, Farnsworth recorded the birds’ calls for later comparison against a computer database of bird calls.
The birds started to arrive at about 8 pm, approximately half an hour after the first moths and bats had begun appearing, Farnsworth said. The birds flew at a height of about 300 feet from the ground and those that strayed into the beams remained anywhere between 2-15 minutes at a time.
Bird traffic around the beams was light at first but gradually became heavier as the evening progressed. The peak occurred at about 2:30 am when there were about 50-60 birds in the beams at once and many more circling nearby. By 4 am, the number of birds had dwindled and the last bird flew through the beams at about 6 am.
Scientists don’t really know why some species of migrating birds are attracted to bright, artificial lights or why they become reluctant to leave once they reach the lights’ source.
“Birds are attracted to the light much the same way that moths, insects, and many other organisms are attracted to light,” Farnsworth said. “They’re attracted to lights mostly under very specific conditions, usually associated with poor visibility, low cloud ceiling, fog and haze.”
It’s thought that under such conditions, the birds have to rely heavily on visual cues to guide them. Many bird species are known to navigate by moonlight or starlight, and some scientists think the artificial lights may be acting as a distraction.
“The theory is that once birds focus on such a strong visual cue, they move toward it and once they get to it they do not want to leave it,” Farnsworth said. “Some anthropomorphize this as fear to leave, but it’s probably closer to simply being overwhelmed by the strength of the cue.”
In the end, Farnsworth and the other observers didn’t witness any bird casualties that could be attributable to the lights and Audubon’s emergency plan was never enacted.
Creshkoff fears that in a few years migrating birds will face an artificial light disturbance that makes the Tribute lights seem pale in comparison.
The Freedom Tower, the building designed to replace the twin World Trade Center towers that were destroyed, is expected to be completed in 2010. Rising 1776 feet into the air, the new tower is expected to be the tallest building in the United States. At night, a 400-foot spire atop the tower will emit an intense beam of light that will penetrate more than a thousand feet into the air above the tower.
“I just shudder to think what impact that will have on migrating birds,” Creshkoff said.
Creshkoff believes people need to become more aware of the impact of artificial lights.
“Light is beautiful; people like it and get aesthetic jollies from seeing the New York skyline lit up,” Creshkoff said. “[But] we need to educate ourselves and realize that light is not benign, light is not a non-event, light does not have zero-impact either on ourselves or other animals.”