While some places could (and should) ban colony traps due too low numbers of rats, we have an extremely high population of them. I'd never advocate the use of them when in an area with low numbers. In fact trappers as a whole should pay attention to the populations in their area and adjust their trapping based on what they see. Prime example. I don't see many ref fox in ANY of the areas I trap, so when I do catch them, they get a free pass from me. Coyotes on the other hand, along with rats and beaver, will get a ride home in the truck because we literally have a ton of them, and not as many trappers as you'd think. So in this case, and in my areas, colony traps are not a population killer like you may think.