All you have to do is leave poison in the infested area, and sooner or later, the problem will eliminate itself. Effective, yes. Environmentally friendly? Not so much. Without debating the actual use of poison, there is a tremendous risk of collateral damage with any kind of toxic pest control substance. After all, when something ingests poison, the poison effectively becomes mobile, traveling inside of the infected animal wherever it goes, until it dies. If a predator catches and eats the poisoned animal, it’s swallowing a biological time bomb that begins wreaking havoc on its own system. In this manner, “rat” poison can easily become “hawk” poison, even when its human user only intended to safeguard his toolshed.
How could something designed to kill small animals affect a large one? In the case of birds of prey, it’s important to remember that raptors weigh much less than their appearances suggest. Even large species, like red-tailed hawks, average only around two or three pounds. The biological reasoning for this is obvious: they fly. In terms of predatory efficiency, they’re nothing short of miraculous, packing incredible strength into a streamlined package. Their lack of bulk, though, makes them extremely susceptible to poisons ingested secondhand.
A hawk weighs more than a rat, but not by as much as you’d think. If a rat, rabbit, or other rodent that ingests poison doesn’t die immediately, it will become weak and lethargic as it slowly falls victim. A weak, lethargic rodent is a sublime target for any raptor, because weak and lethargic equals an easy meal. Predators are hardwired to seize opportunities like that; they have no way to stop and consider why that rat is moving so slowly. They simply see it, and think, hey, that food’s not moving very fast. It must be my lucky day!
So the hawk catches the rat and devours its meal, in the process ingesting every bit of poison in that rat’s system. What if a dose of rat poison is enough to fatally sicken a rat, but not quite enough to down a hawk? The hawk still has poison in its system. Even if it isn’t potent enough to kill it outright, that hawk will still suffer the ill effects of it, effects that can be deadly for an animal that must operate at peak levels to survive. Any kind of lethargy, or bout of sickness, weakens the bird, and reduces its chances of catching its next meal. Missed meals mean an empty belly, and the onset of hunger only weakens the bird further, stressing it and rendering it even more susceptible to the toxins within. It becomes a sad spiral, each misfortune compromising its system further, until the once healthy hawk is every bit as dead as the rat.
That’s not to say that raptors are the only unintended victims of domestic pest poisons; so are dogs, cats, coyotes, and basically every other predator, whether wild-born or the pet next door. There are cleaner ways to get rid of rats, or any other “pest.” Some are humane, like catch-and-release traps. Others, like snap traps, are at the very least, self-contained. Poisons are made to kill; they can be used so easily, but also spiral out of control so readily.
And when they do, there is always collateral damage.