Introduction
Rodent pests are defined as “commensal” because they live in close association with people. When food, water, and shelter are available, we have made a perfect environment for rodents (and other pests).
Food availability
Rodents feed on food items that we grow, harvest, process, store, and discard. Problems exist if people have inadvertently provided a nearby food source, ranging from fresh produce to food and even pet waste.

Water availability
Norway rats need to drink standing water every day. Water can be found in puddles or condensation on a pipe.
Mice will drink water too, but can obtain enough moisture from most food sources to remain hydrated.
Nest site availability
Norway rats prefer to burrow in soil, but will take advantage of voids near a food source. Mice can make nests inside walls, equipment, and other protected places.
