City Life is Hard for Raptors. Can Removing Rat Poison Make it Easier?

Earlier this year, Chicago residents were delighted to watch a pair of Great Horned Owls take up residence in Lincoln Park, a swath of green along the city’s edge, and thrilled in seeing the family grow with the addition of an owlet in spring. “They were not distant creatures that you had to look through binoculars to see,” says Dana Harbaugh, who chairs the advocacy committee of the Chicago Bird Alliance. “They were right there, in the city, in this amazing green space.” 

Then, one by one, the owls started dying. First the adult male, sometimes known as “Papa Owl,” in early April; a few weeks later the pair’s owlet, found dead near the pond where the trio spent their time. Finally, in May, the adult female owl was discovered bleeding out on the sidewalk in front of a nearby home.

Though full reports on these deaths are still in the works, local rehabbers strongly suspect that rodenticides played a role. If confirmed, that would place the Lincoln Park owls in a long line of beloved birds who have suffered after eating poisoned rats. Flaco, the Eurasian Eagle-Owl and zoo escapee who recently  captured New Yorkers’ hearts, also had high levels of rodenticide in his system when he died this year—a debilitating level of poison that likely contributed to a fatal collision with a window or building. (Even before Flaco, other famous New York raptors—such as Barry, the Barred Owl and Lima, the Red-tailed Hawk—faced similar fates). 

The deaths of these avian celebrities drive home the devastating side effects of humans’ perpetual war on rats, which often relies on poisons that spread up the food chain to predators like owls, eagles, and hawks. Wildlife advocates have long tried to limit the use of rodenticides—and efforts to tighten legal restrictions and test out safer alternatives have gained some steam in recent years—but the chemicals remain widespread. Now, some are hoping these tragedies will spur momentum in the fight to protect urban raptors, including those whose deaths fly under the radar.

“There’s so many other animals that don’t have names or fame that have been victims,” says Lisa Owens Viani, who founded the California nonprofit Raptors Are The Solution (RATS) to push for eliminating rodenticides after the poisons killed off a family of Cooper’s Hawks in her neighborhood. “If we want to have these animals living among us, we need to make better choices.”

People have been trying to poison their way out of the rat problem for centuries. In the Victorian era, arsenic was the go-to; these days, the most common forms are anticoagulants, which stop blood from clotting and leave rats to die from internal bleeding. The problem is that, since rats don’t die right away, a hungry raptor may dine on a poisoned rat that’s still scurrying around. And since the compounds from rodenticides can stick around in the body for months—especially in the case of the more toxic second-generation anticoagulants—raptors can rack up high doses as they keep eating.

In this way, rodenticides have a devastating ecological impact as they travel up the food chain, says Jesse McLaughlin, NYC Bird Alliance’s advocacy and engagement associate. At a high enough concentration, anticoagulants can directly lead to birds’ deaths. But even at lower doses, they leave birds slow and disoriented, making it harder for them to survive the challenges of city living. “All of the threats that all the other wild birds are facing—like artificial light and buildings—become a lot more difficult to navigate,” McLaughlin says. A relatively minor injury could turn deadly: “They’ll just keep bleeding and bleeding and bleeding and bleeding, and they won’t be able to heal,” Harbaugh says.

Experts can’t say exactly how many raptors are dying from rodenticides. Full necropsies that can determine why an animal died are expensive, and most states don’t directly track these raptor deaths. But research shows that raptors may be picking up these poisons at alarming rates: Studies have found anticoagulants in 84 percent of dead birds of prey tested in New York City, 100 percent of Red-tailed Hawks at a rehab center in Massachusetts, and 82 percent of Bald and Golden Eagle carcasses from across the country. “The thing that is sort of disturbing is that it’s so widespread,” says Brian Millsap, a raptor researcher at New Mexico State University, who worked on the eagle study. “It’s out there in almost every bird that we’ve looked at.” 

Though there are some federal regulations, including EPA regulations that removed second-generation anticoagulants from store shelves, advocates say these haven’t come close to solving the problem for birds, not least because those rules have exceptions for pest control companies (and a lack of enforcement for online shoppers). The EPA is currently weighing more restrictions as part of its regular review cycle for rodenticides.

In the meantime, action on the state level is picking up. Since 2020, California has had a moratorium in place on the use of some anticoagulants, while the state’s pesticide control agency is taking another look at its approval of the products. This month, a coalition in Massachusetts petitioned the state to suspend permits for rodenticide products, and Connecticut lawmakers are currently considering a bill that would restrict their use. In Canada, British Columbia has established a permanent ban on second-generation anticoagulants, limiting their use to only a few “essential services” like food production facilities. 

Such restrictions often face pushback that point to the real threats that rodent infestations pose to human health and quality of life. But as rat populations have exploded in cities like New York and Chicago in recent years and officials double down on an all-out war on the pests, avian advocates hope cities reframe the fight—and recognize that using rodenticides hasn't been a winning strategy. “We’re never going to completely eradicate rats. And if poison really worked, they would be eradicated already,” Owens Viani says.

Kathy Nizzari, founder of the New York City-based Lights Out Coalition, has seen a real interest in doing things differently. That includes a renewed focus on tried-and-true solutions, such as reducing rats’ easy access to delicious trash and cozy homes in the walls of buildings, as well as novel tactics. Some cities are testing electronic traps, placing dry ice in rat burrows, and even supplying birth control-laced pellets in hopes of controlling rats’ prolific breeding. Loretta Mayer, the scientist who created these contraceptive snacks, says the pellets are “more attractive than pizza” to the rats—though like with birth control pills for humans, rats have to keep eating them to keep up the effects. The strategy is getting trial runs in Seattle and Boston, and legislation to create a pilot program (dubbed Flaco's Law) is under consideration in New York.

Meanwhile, some grassroots groups are focusing on educating their neighbors. After rat poison killed a well-known family of owls—Oliver, Emily, Huey, and Louie—in Safety Harbor, Florida, in 2022, community members joined forces to get anticoagulants off the streets. Dubbing themselves the “Owl Team,” the group went around town asking building owners, local businesses, and pest management companies to switch to less toxic alternatives. 

Fairl Thomas, an Owl Team member and wildlife rescuer, says positive reinforcement is a big part of her efforts: If a business agrees to stop using anticoagulants, the group advertises them as “raptor partners.” Now, she’s signed on over a dozen pest control companies as partners and convinced the city to stop using the poisons in public parks. And this year, a new owl family has moved into the park where Oliver and Emily once lived, which has filled Thomas with both hope and anxiety: “The question is constantly, have we done enough?”

Since the loss of the Lincoln Park owls, the Chicago Bird Alliance is also looking for ways to turn their community’s grief and outrage into action by launching a rodenticide campaign. For Harbaugh, it’s the least we can do for the birds of prey who liven up our urban environments and reconnect people with the natural world. She’s hopeful that fixing the rodenticide problem can help us be better neighbors to the city's raptors: “We just need to get out of their way.”