I'd like to think I'm reverent of animals. I go out of my way to save bees, snakes, spiders, and other forgotten little critters that find themselves in the wrong place (often, my house) at the wrong time (ever, in my house). And as much as I love hunting, killing is the second least fun part of hunting - next to gutting the kill. There's mortality, staring me in the face in its full brutality. But when it comes to rats, well, to hell with rats. They can all die. Today if possible. Not slowly, because that would be cruel. Just immediately.
I live in Baltimore, which is one of the most rat-infested cities on earth (current global rank: #3), and certainly within the United States (ranked between #3 and #9 nationally). "Why" that's the case is a fascinating tale of human history and behavior intertwined with a rodent species (the Norway Rat in particular), and Robert Sullivan's book "Rats" is as good a place to start as any, though its focus is the Norway Rat's invasion of New York City in particular. Here in Baltimore, we (citizens) punish rats, but we hardly make a dent. Rats are trapped, poisoned, fenced out, cemented over, and even shot.
The bottom line with Norway Rats is that if they have a reliable food source and a place to burrow or escape the cold, they will exist. The rats in a habitat can be fully extinguished, but within months, new rats will colonize the area if burrowing habitat and food are present. From that viewpoint, especially within an urban context where it is impossible to change the critical mass of human behavior (particularly, not picking up dog poop and putting trash out in advance of trash pickup), it is impossible to extirpate rats. Instead, for purposes of sanity, sanitation, and perhaps being able to safely let your kids in the yard or grow a garden, the objective has to be rat management or abatement.
Placing a few traps or a few poison (bait) blocks is an exercise in futility. With both approaches, you are virtually certain of accomplishing a few things.
1) You will kill a few, maybe even several, sub-adult and juvenile rats
2) You will educate all the other dominant, reproducing rats to your plan
3) You risk poisoning pets, kids, and other wildlife due to your random bait placement.
Understand that the Norway Rat is a strongly r-selected species, and an invasive species to boot. I encourage you to look up both of those terms, but suffice to say, it means that biologically speaking, the Rat holds every advantage in battle against you. It also means that population control efforts will usually produce non-linear results related to scale of effort, and results that (regardless of scale of effort) inevitably decline in success over time.
In the coming posts, I will explain how some fundamental principles of rat biology, biogeography, behavior, and nutrition interact with the urban landscape and human behavior to create an existence that is heavily tilted in favor of the Norway Rat's survival at your expense. Within those blog posts, I'll also describe how I've used conventional and unconventional methods to intercept rats' needs and behaviors with abatement measures. Generally, those methods would fall into three categories:
1) strategic removal of food supply
2) exclusion from habitat
3) lethal controls
However, I am going to assume that readers like you, being serious about rat control, have already wholly or strategically removed the rats' food supply if you're serious about rat abatement. Yes, that includes dog poop, cat food, bird seed, and leftover veggies in the garden. If you're not ready to control the rats' food supply, you are not ready for the kind of measures, specifically in the lethal controls area, that I'm going to describe for your use. And in some cases, the food supply may not be yours to eliminate - you only need one uncooperative neighbor to ensure that you'll be doing rat control work for years to come. Still - my studies, my test methods, and my plan will help you do that with as minimal an effort and as high success as possible.