The Norway rat is present across the United States and is the dominant pest rat species in most states. It is larger and more aggressive than the roof rat, which it displaces in temperate regions. Norway rats are adaptable to both rural and urban environments. They naturally swim well and hunt for prey animals, especially birds. As human population density increases in cities, so does the number of Norway rats since easier access to food creates smaller territories.
Norway rats prefer to nest in ground burrows. Although they can climb well, they tend to keep to the ground or the lower levels of buildings while searching for food. Because the food provided by people can be predictable, they’ll follow the same route between an established food source and their burrow until something changes. These routes can be
identified by their droppings, rub marks, gnawing or worn
trails through grass.
It’s important to place management efforts within 10 feet of the routes being used repeatedly by rats. Norway rats are not likely to leave routes that lead to an established food source to investigate other sources of food. Traps and stations set on or close to trails have a better chance of success. Baiting snap traps without setting them (prebaiting) can acclimate rats to the traps as well as help determine food preference if several options are provided.