I just noticed, thanks to Shanley's thread, that the availability of dens may greatly affect population size. I thought that the main reason I find so many garters is because of an abundant food source, which could very will be the reason, but then I realized most of the areas I herp and find snakes have piles of old cracked cement blocks or other man made structures that have fallen to waste near them. So I'm thinking this may be the number one limiting factor to garter population size. Just look at the Narcisse dens!