Are We Burning Down Our House to Kill a Rat? Why the use of Second Generation Anti-coagulant Rodenticides is a bad idea, for birds and people

The growing use of rodenticides known as “second generation anticoagulant rodenticides” or “SGARs” is impacting Bald Eagles and other raptors. This threat is emerging at a time when populations of these magnificent birds are rebounding following decades of work to address the harm done by the pesticide DDT. There are many other ways to kill a rat (or mouse or other pesty rodent) – we should not choose poisons that also kill birds.

Second-Generation Anticoagulant Rodenticides (SGARs) are a class of rodenticides, or rat and mouse, poison, marketed for use in managing rodent infestations. The National Audubon Society has had SGARs on our radar for over a decade now, letting our members know over the years about the threats they pose to raptors. Research studies across the country and recent reports from sick and deceased eagles in New England provide evidence that these particular rodenticides pose a growing risk to Bald Eagles as well as Red-tailed Hawks, Great-horned Owls, and other raptors and predators.

Second-Generation Anticoagulant Rodenticides can be bought online by anyone. These poisons are the top result and first sponsored product upon searching “most lethal rat poison” on the internet. A key difference between SGARs and other rodenticides is the half-life of the poison (the amount of time it remains lethal). While a single feeding of SGAR bait is fatal to a rodent, it may take up to five days to actually die and the chemicals can remain in animal tissue for over one hundred days as they are passed up the food chain to hawks, owls, eagles, and other predators like foxes, bobcats, and coyotes. Between 2014 and 2018, a study of 303 deceased eagles found the two most common rodenticides in their bodies to be SGARs. In May 2021, the State of Massachusett's wildlife officials confirmed the first bald eagle known to have died from SGAR poisoning. The liver of that eagle contained three of the four SGARs registered by the U.S. Environmental Protection Agency (“EPA”). This problem has also been documented in Connecticut where a Bald Eagle died from SGAR consumption this spring. SGARs are not just a threat to rodents and predators, they also pose a significant threat to children and pets, the primary reason that the EPA decided to restrict their use.

Compared to other rodenticides and pest control methods, one might refer to SGARs as the proverbial “nuclear option.” In 2008, the U.S. Fish and Wildlife Service and its partners deployed SGARs by helicopter to treat a number of rat-infested islands to restore the ecosystem. The Rat Island “restoration” project resulted in the death of 46 Bald Eagles, a Peregrine Falcon, and hundreds of other birds representing 24 species, which were found dead among the rats. That same year, the EPA declared that SGARs posed an “unreasonable risk” to children, pets, and wildlife. The EPA phased out direct sales to residential consumers with a goal to “reduce rodenticide exposures to children and non-target wildlife while ensuring residential users, livestock producers, and professional applicators access to a variety of effective and affordable rodent control products.”

The EPA regulation still allows SGARs to be legally used and applied by “commercial pest control and [bought/sold in] structural pest control markets,” though they are sold in bulk quantities online. It is unclear how the EPA can allow unrestricted online sales to constitute “structural pest control markets” since there are no certification checks or safeguards to ensure that online purchasers work in commercial pest control. Putting aside the widespread and problematic availability of large quantities of SGARs online to ordinary consumers, even when applied by certified professionals according to instructions and in full compliance with the law, these poisons are still an active threat to raptors and wildlife. The ease of domestic access, permissible commercial use, and mounting avian fatalities are evidence that the EPA’s regulations are not strong enough. In response, states are beginning to act in the face of EPA’s failed approach.

At the end of 2020, California became the first state to ban SGARs sale and use. Most uses of SGARs will be prohibited in California until the Department of Pesticide and Regulation determines, in coordination with the Department of Fish and Wildlife, SGARs use will not harm non-target wildlife. The California law includes exemptions to cover situations where a rat infestation poses a threat to public health. Massachusetts introduced legislation in both the House and Senate that would require public learning institutions to adopt integrated pest management strategies to minimize SGAR usage and require digital reporting. In New Hampshire, the legislature is considering a bill prohibiting SGARs, with exceptions similar to California. Additionally, the legislature in Connecticut introduced bills banning the application, sale, use, and distribution of SGARs. Finally, the State of Maine is participating in a regional study to understand the impact of SGARs on predators such as fishers.

Audubon Vermont is collaborating with these states to determine a potential legislative response in the Green Mountain State and hopes to build support for similar legislation here. The basis for the need to act is simple: SGARs are killing raptors and other wildlife and there are ample alternatives. SGARs are less effective than snap traps and about half as effective as cats for rodent management. More than 175 rat poison products, which do not pose the same level of risk to raptors and other rodent-predators, can be bought on the open market. Many basic non-lethal preventative measures can reduce rodent infestations. Finally, and ironically, healthy populations of raptors and other wildlife will reduce rat and other rodent populations.

Since most of the other New England states are taking affirmative steps to restrict the use of these poisons, it is time that Vermont joins this effort. In the meantime, please avoid using or purchasing SGAR products (any rodenticide containing Brodifacoum, Bromadiolone, Difenacoum, or Difethialone). Additionally, please encourage any commercial pest applicators you hire to avoid using SGARs.

Thank you for doing your part. Bald Eagles were only removed from Vermont’s list of endangered and threatened species last year. We do not want to see populations of our national symbol, or of any other hawk, falcon, or owl begin to decline after so many years of hard work to recover the populations of these amazing creatures.

How you can help, right now