The Cliffs of Lower Manhattan

New York City holds more people than any other city in the United States. It is also believed to hold more peregrine falcons than anywhere else in the world. This bird, known as the fastest animal on Earth, regularly reaching over 200 miles per hour, can also be found nesting on the Verrazzano-Narrows Bridge, the Marine Parkway, and on office towers in Lower Manhattan.

Throughout its time on this planet, a peregrine has evolved to hunt its prey from cliffs. While there are no cliffs in New York, we might have unintentionally built something close enough, and a bird that nearly went extinct moved in.

I’d always thought of a city as the concrete and steel that replaced a former ecosystem, but that’s not the case at all, and living in New York this summer has made it clear. But the thing I keep returning to isn’t that animals have found a way to acclimate to their new environment; it’s that almost nothing in this city was built with any of them in mind. Sometimes our indifference can save a species. Sometimes it kills them at rates nature didn’t intend. Mostly the difference is a matter of luck.

Sixty years ago there were no peregrines in New York City at all. DDT moved up the food chain into birds of prey and thinned their eggshells until the eggs collapsed under the weight of the mother sitting on them. By the early 1960s, the peregrine was gone from New York State as a nesting species, and gone from the entire eastern United States. The person who made the public understand why was Rachel Carson, who died in 1964, eight years before the pesticide was banned.

What brought the falcons back was the ban and a captive-breeding program that released young falcons between 1974 and 1988. And what they came back to was a different city than the one their ancestors left. In 1983, a pair was spotted nesting on a New York City bridge, the first in decades. Today, studies show that urban peregrines successfully nest at 94% compared to 78% for their rural counterparts. Nobody built the Verrazzano for a falcon. We built a high ledge over open air with an overabundant supply of pigeons underneath it, and a predator looking for a cliff to nest on recognized the shape.

The return of the peregrines is not evidence that development is harmless—the falcons recovered because of environmental actions to ban DDT and conservation efforts to repopulate the species, not because we built bridges. However, it shows me that the built environment isn’t automatically hostile. The steel and concrete that scales the city and often discussed as a loss of environment can also be a habitat for more than just one species.

Thirty-eight years after the pair of peregrines were spotted on the bridges of New York City, a storm forced migrating songbirds over Lower Manhattan to fly low. The lights of the World Trade Center drew their attention, and when the sun came up, exhausted birds flew into the glass. Hundreds of Black-and-white Warblers, Northern Parulas, and Ovenbirds died in a single morning.

Glass isn’t a surface to a bird. It’s either invisible or it’s a screen of somewhere they can fly (trees, clouds, open sky, etc.) reproduced at life size and full brightness. NYC Bird Alliance estimates that up to a quarter of a million birds die this way in New York City every year. Nationally, a 2024 study puts the toll at well over a billion, higher than earlier estimates because birds that appear stunned and fly off die far more often than anyone was counting. Of the collision victims brought to rehabilitators in that study, only 40 percent survived. In the same city where the towers of Lower Manhattan gave the peregrine her cliffs are the same walls that kill the birds she hunts.

What’s encouraging is how cheap this question is to ask. Since January 2021, New York has required bird-friendly building materials (patterned glass so birds can read it as a barrier) on ninety percent of new façades below seventy-five feet, where most collisions happen. It works, and it only adds a rounding error to construction budgets.

And every September 11, during peak fall migration, when the Tribute in Light throws two beams four miles into the sky over Lower Manhattan, there are volunteers on the ground counting birds. The beams pull migrating songbirds off course and hold them circling so the monitors can watch, and when the number of birds trapped in the light climbs too high, the lights are switched off until the birds scatter and continue north to south.

The falcons might have found their cliffs by accident, but this, building intentionally and sustainably, we did on purpose, and we can keep doing it.

Rachel Carson National Environmental Leadership Fellow Matthew Cherfane

Matthew is a junior in the Departmental Scholar Program at UCLA studying Mathematics and Economics. His current research focuses on the financial benefits of natural infrastructure and the implications of climate collaborative initiatives on competition and prices. Matthew is currently a climate policy fellow for UCLA’s Center for Developing Leadership in Science, focused on addressing systemic barriers to sustainable development, and he previously worked as a sustainability research intern at an asset management firm