Death of Coyote Reveals Poisoned Landscape: New Law May Help
In the spring of 2023, Humane Wildlife Control Inc. was contracted by a small community just north of San Francisco to assess the coyote population and submit a plan for minimizing human-coyote conflicts.
Our investigation revealed the heavily residential, island-like neighborhood was “home" to a single pair of coyotes - a male and female, mated pair. Coyotes are known for being monogamous - until death do they part, and pairs will hold territory, together.
This particular pair defended a territory that included most (if not all) of the small community, routinely patrolling and marking the perimeter in an effort to keep all other coyotes out. Even after the arrival of pups in April, 2024, the pair maintained territorial boundaries.
Toward the end of summer, the pups - close to the size of their parents, began dispersal from the home territory, venturing towards the outskirts of town. Inexperienced, they would dart in front of vehicles. One was found dead on the side of the road.
On the evening of October 21st, a resident of the community reported a dead coyote on their property. It had been observed earlier in the day, weak and staggering. We responded to investigate.
Thinking we would find one of the pups, instead, it was the adult male - the “king”, as we affectionately referred to him. There was no sign of physical trauma but his legs were straight out and stiff, his tail curled upward, and mouth agape, indicative of a painful death - possibly from poison.
We collected the carcass and shipped him to the California Department of Fish and Wildlife’s Wildlife Health Lab for a necropsy and toxicology screening to determine the exact cause of his death.
We received the final report on December 23rd. It suggested the coyote, which weighed 27.6 pounds, consumed antifreeze, resulting in ethylene glycol toxicosis. An additional test is being ordered to confirm this because there’s also the possibility he was exposed to a newly popular rodenticide, cholecalcipherol (Vitamin D3), which could account for the extremely high calcium and phosphorous in his system.
While the possibility of antifreeze being accidentally spilled or intentionally placed in the landscape is extremely concerning, the coyote also tested positive for exposure to six rodenticides - Brodifacoum, Bromadiolone, Difethialone (second generation anticoagulants) as well as Chlorophacinone and Diphacinone (first generation anticoagulants), and Bromethalin, a deadly neurotoxin.
Because anticoagulant rodenticides - often likened to DDT - can transfer from a dead or dying rodent to other animals when consumed, with impacts to entire populations and ecosystems, in 2020, California restricted the use of all Second Generation Anticoagulants, and added Diphacinone as a restricted material in 2023. See the law, HERE.
On January 1, 2025, California will have the strictest limitations on rodenticides in the United States when Chlorophacinone and Warfarin are added to the list of rodenticides prohibited from use in residential settings, parks and wildlife habitats.
There are some exemptions, including emergency situations to protect public health, and certain agricultural settings, but the new legislation holds users liable for unlawful use, with fines up to $25,000.00 per day for each violation.
We hope this story serves as a reminder to anyone who contracts for pest control services to confirm the active ingredient being used. By law, bait stations must be labeled clearly and indicate the poison being used.
Better yet, don’t take the bait.
Use of rodenticide to control rodent populations can be counterproductive, attracting rodents and other animals to a property (for the poisoned food). Poisoned rodents don’t die immediately, but live for a few days in a weakened state where they are easy prey for predators and scavengers, including dogs and cats.
Even more importantly, use of poison (or other lethal control measures) in an "open environment" (i.e. on the exterior of buildings) is pointless, as new individuals will quickly replace those killed by the poison, and so on, and so on, and so on...
Then why are poison bait boxes so widely used? Because it represents big business for the pest control industry (and the regulatory agency that oversees pesticide use). Because, in most applications, rodenticides won't resolve a rodent infestation, pest control companies are guaranteed repeat business.
The ultimate way to keep rodents out of a home - for good, is through exclusion - securing the exterior so they can’t get inside.
To reduce the presence of rodents on the outside of a building, reduce the food and shelter resources they require to survive. Remove debris piles and thin vegetation to reduce harborage, and remove access to food - birdseed, animal feed, compost, garbage.
Lastly, we recommend a reasonable degree of tolerance for mice and rats (and coyotes) in the environment. Complete eradication is not achievable, and attempts to eliminate rodents (or other animals) using poison can have devastating consequences.
Over the last decade, we have demonstrated the effectiveness of a no-poison, no-kill approach. Find out more, HERE.
Subscribe
