DEEP: Rodent Management

Rodent Management

Rat and Mouse Control

Rats and mice are one of the most bothersome pests. They spread disease, such as rabies, ratbite fever, hantavirus and food poisoning. They contaminate food and living areas with their urine, droppings and hair. They can often cause significant damage to structures stored goods and wiring because they can gnaw through wood, plaster, plastic and soft metals.

Rats will also bite sleeping children who may have food on their hands or face if they did not wash up before going to bed.

The most common rodent pests are the Norway rat, and house mouse.

Norway Rat

The larger of the two, the Norway rat is common near sources of water. In fact, they must have water daily in order to survive. They thrive particularly well in areas where garbage is not properly stored. Because they are burrowers, they often dig in rubbish and under buildings or concrete slabs, causing damage to the foundations of buildings or blocking sewer lines.

Norway rats will be active within 50-150 feet of their nests which are often in burrows along foundation walls. They are most active on the lower floors of a building unless there is a large population. They can enter a building through an opening of just 1/2 inch.

They prefer food that is high in protein or carbohydrates but will eat almost anything. Garbage provides them with a well balanced diet.

Norway rats are reddish-brown and heavy-set with a blunt muzzle. The tail is about as long as the combined head and body. Adults weigh 3/4 to 1 pound. Their droppings are 3/4 inches long and capsule-shaped. They have 8-12 young per litter and up to 7 litters per year.

House Mouse

House mice normally live outdoors in fields, occasionally migrating into structures. In houses, they live behind walls, storage boxes and in cabinets and furniture. House mice can survive in almost any environment as the need very small amounts of food, moisture and space.

Mice will usually make their nests within 10-30 feet of their food source. When food is plentiful they may not travel more than a few feet from their nest. They do not need water on a daily basis.

House mice are brown to gray in color with the tail as long as the body. Adults weigh about 1/2 ounce. Their droppings are 1/8 inch long and rod- shaped. They have 5-6 young per litter and up to 8 litters per year.

Rats and mice are active mostly at night with peak activity periods at dusk and again at dawn.

The Rat Patrol

Because rats and mice breed every three to four weeks, you should act quickly to get rid of them at the first sign of their presence. Eliminating their food, water and shelter can reduce their populations rapidly. Some of the ways to eliminate or prevent infestations of rats and mice are:

Rodentproof your home.
Make sure basement windows are secure and are not broken. Seal cracks and openings in the foundation and around pipes, utility conduit, drains and vents using cement, steel wool, metal flashing or 1/4 inch hardware cloth. Exterior doors should be tight fitting and kept closed. Every possible route of entry must be considered. Also, keep weeds, brush and foundation plantings trimmed away from the foundation.

Eliminate their shelter.
Get rid of piles of rubbish, building materials, old cars, furniture, and appliances. Items that must be kept should be elevated at least 18 inches and kept at least 12 inches away from walls and fences.

Starve them out.
Use rodentproof trash cans. Trash cans and dumpsters should be in good condition, tightly covered, with drain plugs in place. Do not leave pet food out for extended periods. Store all bulk foods in tightly covered containers. Place bird feeders on raised platforms.

Eliminate sources of water.
Empty or drain areas where water collects such as buckets, planters, old tires, etc. Cover drain pipes. Fix leaky faucets.

What About Traps & Baits?

When it comes to trapping, it is important to know that rats tend to be very cautious and mice are curious. Therefore, rats may be difficult to trap. Eliminating the conditions that they need for survival controls them best. Use of carefully placed rodenticide baits can be effective if there is an established population.

Mice, on the other hand, can be trapped easily by placing snap traps along walls where mice are likely to travel. Interest in the trap increases if it is baited with peanut butter.

Careful consideration should be given to the use of baits because the chance exists with both rats and mice that they may die in inaccessible areas. The old wives tale that they will leave the building in search of water is not true! Odor and secondary pest infestation is a concern if they die in an inaccessible location!