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Rat poisons having affect on predators, as well

By Staff | Mar 23, 2016

The black boxes which are seen around Sanibel are bait boxes used to poison rats. These rats are then eaten by the local eagles, bobcats and ospreys, which can in turn, have the “anticoagulant poisons” inside them. BRIAN WIERIMA

“You are what you eat.”

Unfortunately for some of the predators in the Sanibel area, that adage holds true and it might be having a negative affect on their health.

An initiative undertaken by the Sanibel Captiva Conservation Foundation’s Wildlife Educator, Dee Serage, is focusing on the use of anticoagulant poison as a means to kill the local rat population.

“The anticoagulant rat poisons are the worst,” Serage said. “The second-generation anticoagulant are even worse, because now, it is taking 20 to 30 times of feeding by one rat to kill them (because they have built an immunity to it), so that fills them up with the poisons, which in turn, the eagle feeds on the rat.”

Predators of rats which are affected by eating poisoned-filled rats include bald eagles, owls and bobcats. Second-generation anticoagulants include brodifacoum, bromaiolone, difenacoum and difethialone.

“Just say no to these second generation anticoagulants,” Serage added.

Three ingredients which are not anticoagulants include bromethalin, cholecalciferol and zinc phosphide.

A first-generation anticoagulant which is easier on wildlife is warfarin.

One of the most famous bald eagles which was found out to have had been tested positive for brodifacoum was “Ozzie,” the wildlife cam star which recently perished after being inflicted with injuries during a fight with another bald eagle.

Ozzie’s necropsy found the rat anticoagulant inside him, although that wasn’t the cause of death.

But the same poison was blamed for a recent eagle’s death in Tampa Bay.

“In bobcats, it messes with their immune system,” Serage said. “Tell your pest control service and management company to not use second generation anticoagulants. These anticoagulants are already banned for use by homeowners by the Environmental Protection Agency, but pesticide companies are still allowed to use them.”

The most used contraption to deliver the rat poisons are the black boxes which are laid around condos and businesses by pest control companies. Rats go inside the box and eat the poison.

“Demand that the rodenticide being used is not a second-generation anticoagulant,” Serage advised. “Deal with only the rats which are affecting your house or condo. Plug up all the holes they use to get inside and use snap traps or ‘slim Jims’ instead.”

The problem of rat poison being passed along the food chain isn’t just a Southwest Florida problem, either. In California, 78-percent of mountain lions, 84-percent of foxes and 92-percent of raptors tested had rodenticides in their toxic screens.

“Twenty plus years ago, we had an abundance of barn owls,” Serage said. “We used to have a couple of barn owls which nested on the SCCF grounds for 20 years, now they are all gone.”

Serage credits some condo and house owners for saying “no” to the use of second-generation anticoagulants, as well as the City of Sanibel, which doesn’t use any of it in their facilities.

“Plugging up all the holes and crevices where rats enter your home is still the best rat control,” Serage said.