It can start at the bird feeder, or maybe a public garbage can. Discarded food waste and garbage offer a smorgasbord for small rodents, who scavenge for a living. From there, it only makes sense that the animals who feed on those smaller animals, wild ones and feral or outdoor cats, are attracted secondarily. It’s a whole food chain, right in your neighborhood!
In a city, rodent infestations are nearly guaranteed as populations grow out of control. Where there’s one rat or mouse, there are usually more. Unfortunately, most pest control companies get rid of a rodent problem by the easiest means possible, and that most often means placing bait boxes, full of rodenticide poison, to lure these mice and rats to a slow and painful death. It may be effective, but it’s inhumane. It’s also incredibly short-sighted. As those poisoned animals die, they’re an easy meal for a hawk or a scavenger like a crow, raccoon, or opossum. Even your “indoor-outdoor” cat is at risk. When these animals eat the victims of poison, they are poisoned right along with the rodents.
The poisons most frequently used for rats these days are known as second-generation anticoagulants (warfarin, another anticoagulant, is the first generation of this type of poison). They are considered preferable to other faster-acting poisons because the rats do not die immediately; although ill and disoriented, they can move around for days. This means that the rats do not die in the property owners’ houses or yards, which is considered a plus. But it also makes them easy targets for raptors, crows, ravens, and other wild predators, who eat them and poison themselves or feed them to their offspring and poison the babies they are working hard to raise.
And it is not a humane way to go — for either the intended or unintended victim. Internal bleeding does not coagulate, but puddles in the organs, and the victims often lose copious amounts of blood through the mouth.
At City Wildlife this summer, we are getting poisoned baby hawks and crows every week, and we hear of many more who have died and are not brought to the center. Our colleagues at the Tufts Wildlife Clinic in Massachusetts discovered that 86 percent of hawks and owls tested for rat poisoning between 2006 and 2010 were positive. At our center, every single raptor we have tested has been positive for rat poison, although we do not test every one we get. Sometimes we can treat them and turn them around, but often they are simply too far gone to survive despite our best efforts.
And then there are squirrels, who are also unintended victims of rat poisoning. This summer, people have reported large die-offs of poisoned urban squirrels from disparate neighborhoods in the District. The culprit appears to be improperly administered rodenticide that squirrels ingest along with the rats.
There is now a new, safe, and humane option on the market that is available from some pest control companies. Called Contrapest, it’s essentially birth control for rodents. And there are other many other safe and effective solutions — too many to describe in this article — to be found at saferodentcontrol.org.
All in all, the simplest and most effective way to control unwanted rodents is to look for the source of food that is attracting them in the first place. For some, that may mean taking down a beloved bird feeder. For others, it may mean being more careful with dog feces, which rats consume avidly, and trash, or by contacting the city for help with a broken or overflowing public trash receptacle.
But by all means, for the sake of all of the animals, please do reconsider using rodenticide. Ultimately, it’s a short-sighted response to what is essentially a man-made problem. And if you see a bait box in use, consider speaking with your neighbor, or building management, and urge them to reconsider. In the long run, you’ll be helping more animals than you even know.