New York CityThey’ve been called “tree rats,” maligned in pop culture, and otherwise ignored as urban pests. But the humble eastern gray squirrel is finally getting some time in the spotlight, thanks to the first-ever Central Park Squirrel Census.
Last October, more than 300 volunteers fanned out over the famous New York City green space, covering more than 840 acres over 11 days. Their goal: Count every single squirrel they could see.
“I was trying to make an educated guess,” says census logistics chief Sally Parham. “I got a number that was huge and I intuitively halved it. And the difference between the real number and my guess was 212, New York City’s area code.”
Who cares how many of the furry-tailed rodents live in Central Park? Organizers of the citizen science and storytelling project spend a lot of time trying to answer this question for skeptics, or as project founder Jamie Allen calls them, “squirrel scrooges.”
It’s partly because the common species is woefully understudied—we still know very little about the eastern gray’s behavior, biology, and baseline population.
For instance, before 2012, there was a nearly 30-year gap in the scientific literature about the species’ alarm vocalizations, which help them communicate danger to one another.
“Some people are bird people, some people are cat people. Some people love bugs. That can influence choices of what gets studied as much as anything else," says Thaddeus McRae, a biologist at Lee University who wrote his dissertation on squirrel alarm calls.
"Squirrels are cute, but so commonplace to many of us that they become background."
Beyond discovering their basic biology, Allen adds, he’s fascinated by how an animal can thrive so well in the middle of Manhattan, the heart of the biggest city in the United States. (Read more about urban animals in our series Wild Cities.)
Invaders and regenerators
Indigenous to the eastern United States, the eastern gray squirrel was eradicated from New York City sometime before the 1840s, and was later reintroduced to American cities in the mid-19th century.
Due to its ability to adapt to many climates and live alongside people, the eastern gray is also an invasive species throughout Europe, as well as in South Africa and Bermuda.
In England, eastern grays are threatening native red squirrels by both outcompeting them for food and spreading parapoxvirus, a lethal disease to which eastern grays are immune.
And even where it’s endemic, the eastern gray squirrel has destructive tendencies. They are, on par with hurricanes and cyberattacks, a leading cause of power outages across the United States, according to CyberSquirrel1, a tongue-in-cheek website that tracks squirrel-related power outages. In 1994, squirrels chewed through vital powerlines and brought NASDAQ to its knees, halting millions of trades.
But squirrels are also a vital player in their ecosystems. Each fall, the animals hoard seeds and nuts in various places, using their excellent sense of smell to locate the food again when times are tough. In doing so, the animals naturally regenerate forests. They’re also important prey for animals such as raptors, foxes, and coyotes.
In a nutshell
The crowd gathered tonight at the Explorers Club would agree. Among them are representatives from the NYU Department of Environmental Studies, Macaulay Honors College, the Central Park Conservancy, and New York City Department of Parks & Recreation, as well as the volunteers who spent nearly 400 hours in the wilds of Central Park.
The census results revealed that 72 percent of squirrels were seen on the ground, including one under a Dumpster, another lounging near a German shepherd, and—maybe the wisest of them all—an animal perched next to a street cart selling nuts, according to Allen. The highest-observed squirrel was found a hundred feet up in a tree.
The densest cluster lives, not surprisingly, in the Ramble, a heavily wooded interior section of the park. (Read why a squirrel stashed 50 pounds of pine cones in a car.)
The census team also noted behavior, such as personality, and fur color. One hundred and seventy eight squirrels were recorded as boldly approaching humans (NYC Parks discourages feeding squirrels, which can harm them), and 25 percent were observed eating.
As for color, gray dominated, representing 82 percent of the recorded population, followed by cinnamon at 13 percent and black at 3.4 percent.
Mapping squirrel habitat
To help illustrate the team’s findings, cartographer Nathaniel Slaughter projected a map of Central Park on the wall. Little yellow stars representing all 2,373 squirrels glinted like constellations against the blue background of greater Central Park.
Before the October 2018 census, Slaughter and his team methodically walked the park grounds, noting elevations, water systems, monuments, and exposed bedrock to create one of the most detailed maps of Central Park to date.
Of course, it’s impossible to know the exact number of squirrels in the park; the census relied solely on sightings. However when putting together the final tally, the organizers did factor in the potential for counting the same animal twice, as well as the likely squirrels that remained hidden.
As for what's next, it's too early to say, notes Allen, but he plans to continue responding to those squirrel scrooges.
“We do it for you. We do it for the city. We do it for the squirrels,” he says, and “because it makes us happy.”
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