Published 3/6/2025
Rat Poisons Can Make Their Way into Nearby Nature
Living near open spaces offers incredible benefits, but it also comes with a responsibility to help protect the delicate balance of local ecosystems. One significant threat to wildlife, specifically those living in preserves near human developments such as Rancho San Antonio and Fremont Older open space preserves near Cupertino, is the use of rat poison, also known as rodenticide, by surrounding homes and businesses. These poisons, intended to kill rodents, have devastating unintended consequences for predators like owls, bobcats, coyotes and mountain lions, and they also pose a serious risk to household pets.
Rodenticides accumulate in the bodies of rodents after they’re ingested. When predators consume these poisoned rodents, they also ingest the toxins. This can weaken their immune systems making them more susceptible to diseases like mange, a highly contagious skin disease caused by mites. In severe cases it can be fatal. Ironically, by poisoning natural rodent predators, rodent populations can actually increase.
Mange can spread from coyotes to dogs and even humans. While treatable in pets, it can be debilitating for wild coyotes, leading to dehydration, starvation and secondary infections. Remember to always keep dogs leashed while visiting a preserve to limit contact between dogs and coyotes. Unleashed pets can lead to defensive behavior in coyotes, increasing the possibility of conflict and the incidental spread of mange.
In addition to the danger posed to wildlife, rodenticides pose a risk to household pets. Curious cats and dogs, may accidentally consume bait or prey on poisoned rodents, leading to serious health issues.
You can help protect wildlife by choosing safer alternatives to rodenticides, such as snap traps and live traps. Prevent rodent intrusion by sealing entry points in your home, trimming branches that touch your house and removing ivy. Support wildlife-friendly policies by advocating for restrictions on rodenticide use within your community and any homeowner’s associations. Finally, never feed coyotes even if they appear sick, as this can habituate them to humans.
“Midpen continues to take proactive steps to advocate for the reduction of rodenticide use in our region to limit its effects on local wildlife,” Midpen Wildlife Biologist Matt Sharp Chaney said.
Midpen actively supports legislation aimed at reducing the harmful impacts of rodenticides on wildlife, including the 2023 California Ecosystems Protection Act (AB 1322) and the 2024 Poison-Free Wildlife Act (AB 2552).