Rodents are prolific breeders and can reproduce at amazing rates. The three rodents of concern in our area are the House mouse, Norway rat and the Roof rat. They all have some differences in behavior which can be used in determining control methods.
Rodents have a home range they spend most of their time in. Mice live in smaller territories ranging 10-25 feet. Rats range around 100 feet and live in colonies. Rats usually eat their entire meal for the day at one time, usually at night while mice eat small amounts of food several times during the day. Rats are more wary of new objects, so it may take longer for success with bait stations and traps to be effective. It may take at least 5 days for the rat to accept the new object while a mouse may accept it overnight. Rats are also pickier eaters and like fresh food while mice are more curious and more willing to try new foods.
Rats can produce 10-12 litters per year with an average size of 6-8 babies. A single rat pair can
produce 15,000 descendants in only one year! The reproduction rate for mice is similar with 5-10 litters per year with 5-6 babies.
Front incisor teeth on rats - grow on average 5 inches per year, so rodents gnaw constantly to keep them worn down.
Rats can climb both horizontally and vertically. They jump vertically as much as 36” from a flat surface and 48” horizontally from a flat surface. They can swim as far as ½ mile in open water and travel against sewer lines in substantial water currents. Rats can also survive falls of up to 35 feet.
Following are best practices for rodent control:
Sanitation practices: minimize and clean up feed spills, mow around buildings/houses to decrease cover, throw away garbage frequently, and not stack lumber and other construction debris near buildings. Exclusion is a lot harder in hog or poultry houses themselves, but focus exclusion practices in offices, storage buildings and pump houses. Exclusion includes sealing cracks or openings in the building. Leave no holes larger than ¼ inch. Doors, windows and screens should fit tightly. Leave a three foot wide vegetation free buffer area covered with gravel around hog and poultry houses.
Population control: trapping can be an effective way to control rodents. Trapping rats may require more skill and labor. The advantages to trapping is that it doesn’t rely on potentially
hazardous rodenticides, success is visible, it allows disposal of carcasses, and can eliminate odors. There are several available traps which can be single trap or multiple-capture live traps.
Rodenticides (toxic baits): baits are formulated with an attractant and a rodenticide in them. Some baits may be restricted use pesticides (RUP) and require a pesticide license. There are anticoagulant and non anticoagulant rodenticides. Each of the rodenticides work in different ways to kill the rodents. There are situations where each type may be a better choice.
Bait stations with rodenticides and placement is critical. Using a bait station targets the rodents and allows them to feel secure while eating the bait. Proper placement and maintenance is critical. Always wear gloves when putting out bait for your protection as well, as rodents will avoid the bait stations if they smell human scent on them.
There are typically two types of classifications for rodenticides: multiple-feed poisons or single-feed poisons. Depending upon the active ingredient, the product may be used in different ways. It’s extremely important to read and follow the label instructions because all types of
rodenticides are poisonous and can put other animals at risk that are not the target animal of the rodenticide. Be sure to read the manufacturer information and warnings. The poultry industry usually prefers to use the single-feed poisons because rodents can potentially receive enough to kill them after only a couple feedings, whereas multiple-feed poisons take much longer.
To be effective in implementing a rodent control program, you must be monitoring and evaluating the program constantly. There are several reasons rodent programs may not be successful: not enough bait stations, the control area is too small, not enough exposure time to the bait, easy access to other food supplies, not stocking bait stations on a regular basis, choosing the wrong bait, moldy or old baits, and not rotating baits. It’s very important to properly handle rodenticides. Keep in mind the home range of the mice and the rats so you’ll ensure you have plenty of bait stations.
Planning, preparation and persistence are the “3 Ps” of rodent control. Remember them and you’ll be money and time ahead.