It’s making reference to logistic curves and how rabbit populations, which can grow exponentially, will oscillate between a low and high population size.
In short, it explains why some years there are a shit ton of rabbits, and other years, very few.
There’s something I call a “pill stick”, into which you put it in the barrel, jam it into the cats mouth while holding their jaw and then push the trigger. Requires a little finesse but easier than other methods.