We’ll stipulate, as the lawyers say, that no city dweller wants rats around.
But the answer shouldn’t be to over-poison the environment, putting all sorts of other urban wildlife at risk.
Last week, as Mohammad Samra reported in the May 10 Chicago Sun-Times, the last of a popular family of great horned owls living near Lincoln Park’s North Pond Natural Area died after apparently eating rats that had been poisoned. Annette Prince of Chicago Bird Monitors says owners of residential and commercial buildings have ringed North Pond with rat poison boxes.
The avian tragedy echoed the untimely end in February of Flaco, a beloved Eurasian eagle-owl in New York that died after a building collision. Flaco had survived for a year after escaping from the Central Park Zoo, but at the time of his death, his body was found to be carrying a level of rodenticide so high it would have been disorienting and debilitating, which may have led to the collision, according to the American Bird Conservancy.
“We try to make inviting spaces to enjoy wildlife and nature, and right next to it we put these potential poisonings,” Prince said. “It’s a problem. Homeowners go overboard.”
Going overboard is easy with second-generation “super toxic” anticoagulant rodenticides, although the U.S. Environmental Protection Agency now limits the sale of the most potent rat poisons to commercial use.
Rat control experts have long said the best way to tamp down a rat population is to remove food sources. If food is plentiful, a pair of rats and their successive litters can turn into more than 1,000 rats in a year. Property owners can’t poison their way out of those kinds of numbers.
But if you drive along many of the city’s alleys, it’s easy to spot overflowing garbage containers or rusted containers with holes large enough to admit rats, which can squeeze through an opening the size of a quarter. Fixing that would go a long way toward reducing the urban rat population.
So would other measures, such as ensuring food is not left out on a property, eliminating potential nesting areas or inserting dry ice pellets in outdoor rat holes while closing the entry points.
Once poison gets into the food chain, it kills predators that help control rats. An owl will catch and kill up to 12 rodents in a night. Coyotes, hawks and foxes also eat rats. Squirrels, snakes, chipmunks and mice might get into traps put out by the city, property owners or commercial services, ingesting poison and passing on that poison to predators, where the toxins build up in their bodies, a process called bioaccumulation.
When confronted with pests such as rats, it’s tempting to bring out the heaviest possible artillery. Rats can carry disease, destroy food and damage property. But as with other environmental issues, there is a cost to using poison. Indiscriminately spraying pesticides on lawns and gardens, for example, has had a bad effect on bird populations.
Even low levels of rodenticide can render birds and animals sluggish, weak and disoriented. High levels can cause bleeding, shock and death. As for people, they can suffer serious health effects just by one instance of breathing in or touching most rodenticides , according to the National Pesticide Information Center.
In 2013, the U.S. EPA put rules in place to protect children and pets from rat poison, but those rules leave wildlife at risk. It’s time for a comprehensive approach that does a better job of eliminating rats while also protecting people and local fauna.
When people are lucky enough to see owls make their homes in the city, it would be nice to know those owls are not being slowly poisoned.
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