They can consume as many as 200 sawfly cocoons per day. The shrew has an even better record. It can gobble its own weight in grubs and cutworms in just 3 hours, and has been observed to eat over three times its own body weight day after day. This is why fencing critical areas is the most effective control measure you can employ. However, in urban settings, these populations can quickly expand to nuisance proportions in the absence of their natural predators.
Most municipalities have ordinances against trapping and relocating 'rodents'.
Some states with serious urban pest problems have begun consideration of moderating homeowner restrictions. If you are an Illinois resident homeowner, a permit will be issued for this purpose, if you contact the biologist in charge of your County, and if you have the correct answers to his or her questions. Personally, I think that re-introduction of cougars and coyotes might be more helpful, though quite unworkable. Professional exterminators received numerous calls this year for removal of ladybugs seeking warm places for winter hibernation. If the American public freaks-out at the sight of a bee or a ladybug, one can imagine the outcry if a natural predator should be spotted during daylight hours.