It will probably never be known whether Flaco, the Eurasian eagle-owl that stole our hearts, died because of a collision with a building, herpes from eating pigeons, the ingestion of lots and lots of rat poison, or some combination of the above. But what's clear from his necropsy report is that New York City's natural foodways, especially for rat-eating raptors like Flaco, is completely suffused with rodenticides, and our absolute refusal to do anything with our trash but collect it in huge piles on the ground helped speed Flaco's demise.
According to the report, Flaco was exposed to four different anticoagulant rodenticides that are "commonly used for rat control in New York City." Those rodenticides can often be found in black bait boxes, which are placed by building superintendents, pest control workers, and parks employees, on what seems now like every block in New York City.
Why are the bait boxes so popular? Because New York City has a lot of rats. Why does New York City have a lot of rats? Because, unlike virtually every other city in the United States, we still pile our garbage in huge piles on the street, allowing rats to feast and their population to grow without bound, creating a nuisance for residents and real health risks to people who come in contact with them.
New York City has finally been considering ending this buffet, with a slapdash mandate to have private businesses containerize their trash, and a plan that will eventually bring containerization to all five boroughs.
"For the rats, the number one thing that has to be done is containerizing waste," Clare Miflin, an architect and founder of the Center for Zero Waste Design, which has been pushing the City to move forward with containerization, told Hell Gate.
As the rat population has soared in recent years (especially after trash collection was cut back during the pandemic), the black bait boxes have become near-ubiquitous—hardly cutting into the rat population as a whole, but poisoning the birds that feed on the rats.
"Right now, we suspect that 85 percent of raptors have varying levels of anticoagulant rodenticides in their bodies, and we've seen a huge uptick recently," said Emily Einhorn, the animal care manager at the Wild Bird Fund, who's been studying the use of rodenticides in New York City and the impact it's had on bird populations. "It's all too common for us to get raptors in which either the primary cause of intake is anticoagulant rodenticide toxicity, or as a possible secondary cause like Flaco, where we have a window-glass collision," Einhorn said. "But whenever there's anticoagulant issues and then internal hemorrhaging, they're completely impaired when they're flying."
Einhorn has seen a new generation of rodenticides enter the market in recent years, wreaking havoc on the city's bird population. Meanwhile, their use is going seemingly unchecked by federal or state regulators.
"They're super cheap to make, there's no consumer regulation, they last a long time in the environment, and they're getting used more and more frequently," Einhorn said. "In New York City, we're seeing birds get decimated."
Would trash containerization get rid of all the rats in New York City? Probably not—but it would help make the city's rat problems far less acute, possibly opening the door to more direct methods for getting rid of rats, like gassing them with carbon monoxide. The indiscriminate use of rat poison is also working against one of the most efficient rat-killers the city has at its disposal—the raptors themselves.
"You're actually killing one of the things that would help keep rat populations in check," said Bryce Robinson, a graduate student at Cornell who studies, among other bird-related subjects, the adaptive diets of raptors. "You're going hard at fighting the problem, but you're also fighting against something else that's fighting the problem."
Robinson said he doesn't think that by actually containerizing trash, other bird populations in the city, like pigeons or sparrows, who often feed on trash themselves, would feel that much of an impact.
"Sparrows, starlings, pigeons, they're ubiquitous across North America because they're quite successful in finding out a way to survive in particular situations," he said. "They'll find food, even if we lock it up. I don't think that it will have an appreciable impact on their population."
So how do some raptors continue to live in the city, like the mating pair in Tompkins Square Park, even as rat poison is seemingly everywhere? Robinson said it's simply a matter of age, sex, and immune system. Female hawks are larger than male hawks, meaning they can handle more poison in their system, while some hawks just have a stronger immune system than others.
But with newer, stronger rat poisons, and the proliferation of the poison boxes, Einhorn has found that even long-tenured birds are falling sick and dying, including a nesting pair up at Columbia University.
"The more recently made rodenticides are taking them out very quickly," said Einhorn.
And while New York City Parks often celebrates its resident raptors on social media, the Parks Department itself distributes the poison boxes throughout the City's parks, even during fledgling season, which is about to begin.
"Red-tailed hawks and great horned owls in the city are making their nests right now, and usually within 100 feet, you can find a bait box. And that's what they're gonna be feeding their chicks," said Einhorn.
Einhorn thinks there are better ways for New York City to deal with its rat issue, including options like trash containerization, to head off the still-unknown impacts of the current crop of rodenticides. She pointed at the appearance of DDE (a breakdown product of the now-banned pesticide DDT) in Flaco's toxicology as an example of the longevity these poisons have in our ecosystems.
"I just wish for one moment that humans remembered we're mammals, too," she said.
In death, it's possible that Flaco can help remind New Yorkers that we're connected to a much larger ecology, and that the poisons we so wantonly distribute on city streets don't just stop at killing rats.
The Center for Zero Waste Design's Miflin sees our trash, rats, and birds as inextricably linked: "We can't rely on nasty chemicals. We have to design better systems."
