It was a rainy Sunday evening when my partner and I found ourselves searching for a barred owl that was reported to have collapsed in a playground sandbox for many hours. When we finally found him, he was barely breathing. We placed him in a cloth-lined box and brought him to a raptor rehabilitator. But the barred owl died en route, choking on his own blood from a spontaneous lung hemorrhage. The owl’s autopsy (known as a necropsy) found the owl’s liver contained lethal levels of a kind of rat poison known as second-generation anticoagulant rodenticides, or SGARs. These toxins thin the blood to the point where something as simple as a sneeze can cause massive — and often ultimately fatal — internal bleeding.
This owl had been exposed to SGARs by eating rodents that eat the bait from the thousands of bait stations containing these poisons that blanket my neighborhood and countless others. These bait stations are distributed en masse by pest control companies. A rodent will feed numerous times from these stations over the course of several days or weeks while the poison bioaccumulates in higher and higher doses in their systems. By the time a predator catches and consumes these rodents, they are brimming with enough poison to kill those predators as well.
The barred owl in my neighborhood was not an isolated incident. Over the next nine months, my organization, Save Mass Wildlife, funded the testing of 40 animals that were discovered dead in private yards and public parks or had perished on the way to or in rehabilitator care in my town and a few neighboring ones. All of these animals were found to have been exposed to SGARs, and all but a couple were exposed at lethal levels and exhibited — usually significant — internal bleeding. These mostly included birds of prey like hawks and owls, but also skunks, foxes, coyotes, chipmunks and squirrels, as well as a snapping turtle and a great blue heron — all dead due to anticoagulants. Separately, the state of Massachusetts confirmed that three bald eagles in my town died due to SGAR exposure. These were the first eagles to nest and hatch here since DDT extirpated the species from New England several generations ago. The cemetery where these eagles first nested was surrounded by buildings and businesses that featured scores of SGAR-containing bait stations.
In New Hampshire, bald eagle and snowy owl mortalities from SGARs have also been reported. One such case was Seabrook, the snowy owl, who had to be admitted into care multiple times with SGAR poisoning and did not survive his last intake. The tragic irony is that by killing off rodent predators, we actually increase the numbers of rats and mice. A single owl eats thousands of rodents in a year. Studies show that house mice and rats are increasingly resistant to SGARs, which means they can eat the bait for prolonged or indefinite periods without a fatal impact. However, their predators are not resistant and so are much more vulnerable to SGARs than their prey.
The New Hampshire Legislature had an opportunity to ban SGARs this past spring but killed the bill. Meanwhile, the state’s Pesticide Control Board is only taking action to prohibit consumer use of SGARs, while still allowing the pest control industry free rein to cover our communities with bait boxes harboring these poisons. Save Mass Wildlife recently funded a bus campaign in Manchester that reminds the public that it doesn’t matter whether the person applying these poisons is a pest control professional or a consumer. The end result is the same: wildlife will die. As a New Hampshire resident, you don’t have to take the state’s inaction sitting down. In 2022, a group of activists and I persuaded our local town meeting to prohibit SGARs — and more recently, all anticoagulant use — on public properties in our municipal borders. Since then, dozens of other communities in Massachusetts and Connecticut have followed suit. It’s time for New Hampshire to join the fray and show their state representatives that its residents cherish its wildlife and will rise up to defend them.
Laura Kiesel is the author of a forthcoming book with Princeton University Press on the impacts of rat poisons — particularly anticoagulant rat poisons — in the United States.