Rodenticides Don’t Just Kill Rodents; They Kill Children, Pets, Birds and Other Wildlife!

It was unusual to hear scampering coming from overhead. Our dogs have not yet mastered climbing into the attic space, so we knew it was something uninvited. Rats! I’m fine with the wood rats that live among the trees and make middens, but we can’t have rats in the house.

Rob, claiming that he was thinking like a rat, crawled around the roof, the deck, and foundation looking for potential access points. The most important step was to seal off all the ways that they might enter the house. Worse was figuring out how to get rid of the rat that was already inside. We made the unpleasant decision to use a snap trap, even though neither of us are fond of killing animals. Most people don’t like snap traps; they consider them gory. But they are far more humane than the alternative of rat poison.

The newest rat poisons are slow acting anti-coagulants. They prevent clotting resulting in thirsty, hemorrhaging rodents staggering around in the open. This makes them highly tempting and easy to catch by predators. Because predators generally eat many rodents as part of their diet, the rodenticides accumulate in their body, often lethally. A barn owl can eat around 4,000 rodents in a year. But for owls today, capturing and eating their main food source could prove deadly. Even when exposure is not fatal by itself, the increase in anticoagulant levels causes disorientation and weakens the immune system.

Alarmingly, thousands of children and pets are poisoned each year by rodenticides. In addition to owls, many other non-target animals are also poisoned. Studies have found rodenticides in foxes, fishers, bobcats, cougars, coyotes, California Condors, and nearly every species of hawk and owl, as well as in scavengers such as raccoons, skunks, and opossums.

Data collected from studies illustrate the pervasive nature of the problem: 62% of 186 dead wolves collected from 2018 to 2022 carried at least one rodenticide in their bodies. 100% of 43 red-tailed hawks admitted to the Tufts wildlife clinic from 2017 to 2019 carried rodenticides. (All died.) Another clinic tested dead Bald and Golden Eagles and found that more than 80% carried rodenticides.

The best way to deal with a rodent problem is to limit attractants and prevent rodents from entering your home. If you must get rid of a rat already in the home, use a humane quick method of elimination (snap traps, electric charge traps). Do not use inhumane methods such as sticky glue traps. These capture a host of off-target animals. The Cascades Raptor Center reports a number of patients that have been stuck in glue traps. Do not use rodenticides. There is no rat poison that is safe for birds.

Although the EPA limited purchase for some of these toxins, they are still readily available and data indicate that the regulations did not decrease reports of non-target poisonings. Ironically, when we poison the owls, hawks, and other predators, we lose our most efficient form of pest control. Most people are simply not aware of the problems with the rodenticides and glue traps that we can easily purchase at stores and on-line. Help spread the word.

How to eliminate the need for rodenticides.

• Seal entry points. Cover any openings more than a quarter inch in diameter with ¼ inch hardware cloth or wire mesh. Use steel wool or copper mesh to create a barrier in holes that cannot be plugged.
• Remove attractants like food and garbage. Keep outdoor grills and cooking areas clean. Keep all garbage and food in tightly sealed containers. Do not leave pet food out.
• Backyard chicken coops may attract rats. Install rat-proof flooring in your coop. Pick up the food scraps. Seal all feed in tight containers. Feed chickens inside their rodent-proof coop.
• Compost piles should be contained in small-mesh wire.
• Keep firewood off the ground.
• Clean the ground around bird feeders or use catch trays or no-mess seed mixes.
• Remove invasive ivy—it’s a luxury hotel for rats.
• Install rodent fertility-control bait stations.
• Remove existing rodents with snap or electronic traps.
  If you live in an area where rodenticide is not being used, install barn owl nesting boxes to draw owls who’ll control rodents naturally.

by Debbie Schlenoff, debbie@ccbirdalliance.org