Rat & Mouse Control
Least-Toxic Mice and Rat Control
Whether your house is being visited by mice or rats, the steps you must take to get rid of them are similar:
- Remove the attraction (food, habitat)
- Cut off access into the house (similar to weatherproofing)
Mice generally are easier to deal with than rats and can often be gotten rid of by just removing food sources and plugging up obvious holes. Rats can be more persistent and can require more house proofing and yard clean-up. They are also intelligent and can be difficult to trap. Whichever type of rodent problem you have though, the following suggestions will work to rid your home of rodents without dangerous chemicals.
Removing the Attraction
It is important to remove all food sources from the home, especially the kitchen, including:
- Store foods, particularly grains, in tight fitting metal or glass containers
- Keep fresh fruits and vegetables in the refrigerator
- Clean up all food droppings, including in the oven
- Store compost, organic waste and garbage in containers with tight fitting lids
- Remove pet food after the pet has eaten
- Clean dirty dishes immediately or submerge in soapy water
- Give the kitchen a periodic, all-inclusive cleaning
- It is also important to remove any nesting materials that may be attracting the rodents:
- Stored materials in an attic or basement, typically fabrics or papers, are commonly used for nests. Put materials in rodent-proof containers or discard.
- Removing outdoor food and water sources close to the house is especially important when dealing with rats or wild, seasonal mice (which commonly come into the home in Fall.) Removing habitat, such as wood and debris piles, compost heaps and sacks of seeds or pet food is important. Fallen fruit from trees should also be removed and all garbage should be in enclosed garbage bins. Remove cat, dog, and horse feces daily, since rats also feed on this type of organic waste.
- Rat proof your compost bin by lining with strong wire-mesh, removing meat and fatty foods from the pile, covering or burying fresh scraps into pile, and turning pile to increase the composting speed.
- Rats can nest in dense vegetation, which provides both food and shelter. To discourage them from taking up residence in your yard, prune any low woody shrubs growing next to the house or garage, to expose at least 18 inches of the trunk (rats don’t like exposed ground and can’t reach up above about 11 inches). Prune trees and large shrubs to leave a gap of at least three feet between the branches and the roof of the house or garage, to discourage roof rats.
Cut Off Access
- Fill access holes. Even small holes should be searched out and stuffed with steel wool, covered with sheet metal or filled with caulk. Rodents can eat through wood, paper or plastic so use metal or durable caulk.
- Start with filling the holes in the areas around where the rodents have been spotted, usually in the kitchen area.
- Serious rat problems will require more rat-proofing of home exteriors. You may need to work with a professional pest-control company to ensure that all rat entry points into your house and garage at ground level and at roof level have been identified and secured. Here are the most important:
- Check foundations and walls for cracks and holes that develop from normal house settling and rocking; caulk or fill the openings.
- Cover all ventilation openings to crawl spaces, basements, and attics with sturdy wire screen; also cover the tops of ventilation pipes for dryers, heaters, stoves, etc.
- Ensure that doors to basements and crawl spaces fit tightly into their frames; metal kickplates prevent rats from gnawing entry space in the bottom edges.
- Install sheet metal cuff-type barriers on gutter drainpipes and plumbing pipes, to discourage rats from climbing them.
- Ensure that rainwater flows properly through your roof gutters and out away from the house: clogged gutters lead to softened, rotted wood that invites pest invasions.
- Install screens in the drains in basement and shower room floors.
- If you have a bird feeder, make sure that it is inaccessible to rats and is not serving as a late-night rat buffet table.
- Get a cat, if possible. Females tend to be better mousers.
- Live traps or snap traps can be used for mice. Avoid using sticky glue traps, as they are inhumane and the rodent can be in pain for hours or days before they die. Avoid poisons, as the rodents often retreat into the walls to die, causing odors. Using live traps for rats requires special care. Unlike raccoons, skunks, moles, etc., rats live primarily as parasites among human populations, depending on humans for their food supply. Releasing them elsewhere simply means that they will quickly find their way back to your (or someone else’s) house. There is, in addition, the danger of handling them; their bites can cause disease. Be sure to release them in an uninhabited area and to take special safety precautions.
- Be sure to use enough traps, 5 to 10 traps per hole, spaced 2 ft to 3 ft apart at right angles to the wall. The bait and trigger end of the trap should be facing the wall. Place traps along walls and along known rodent pathways.
- Wear gloves when handling the traps and handle them infrequently because rodents can detect human smells.
- Use sticky baits, such as peanut butter mixed with mixed oats, raisins, baked breads, gum drops, etc.
- Rodents are fairly smart and are suspicious of new objects, so place traps with bait but unset for a few days to get rodents used to them. Once they take the bait, set the trap.
- Most trapping fails because too few traps are used.
Mice and rats are very hard to control if there is a food and water source for them. The first step is to eliminate water and any form of food that is exposed, even crumbs. Thorough cleaning is important. Next eliminate the access. Stop up all holes, cracks and crevices where the rodents would have entry into the house, office or whatever. Repellents can now work. Try hot pepper dusts and sprays. Live traps sometimes have to be used, but the best control is still - cats!
The best traps are snap traps that are inside protective bait stations. The best place to set traps is close to walls in areas where rodents run. The selection of baits for trapping is important. Baits should be fresh and changed daily. Use a variety of baits on traps rather than a single kind of bait. Fruit, peanut butter and nuts all make good baits.
A small, scaly-tailed mouse with a distinct notch in the cutting surface of upper incisors (seen best in side view); hair short; ears moderately large and naked; upperparts ochraceous, suffused with black; belly buffy white, or buffy, usually without speckling and with slaty underfur; yellowish flank line usually present; tail brownish with black tip, not distinctly bicolor, but paler on underside; ears pale brown, feet drab or buffy, tips of toes white. Mammae in four or five pairs. External measurements average: total length, 6.5 inches; tail, 3.5 inches; hind foot, 3/4 inch. Weight of adults, 1/2 - 3/4 oz.
Although not native to North America the house mouse, since its early accidental introduction at most of our seaport towns, has become widespread throughout the United States and occurs either as a commensal or feral animal in practically all parts of the United States.
As commensal animals, house mice live in close association with man - in his houses, outbuildings, stores, and other structures. Where conditions permit, feral mice may be found in fields, along watercourses, and in other places where vegetation is dense enough to afford concealment. These feral animals make runways through the grass, or they may utilize runways made by rats and other meadow-inhabiting species. In the agricultural regions where irrigation is practiced house mice often are found in the vegetation along irrigation ditches, sometimes sharing common runways with native mice.
Although largely nocturnal, house mice are moderately active during the day, chiefly in their quest for food. In the wild they feed on a variety of plant material, including seeds, green stems, and leaves. Alfalfa hay, either in shocks or in stacks, affords an ideal source of food supply and, consequently, it is frequently infested with these mice.
House mice feed on practically any type of food suitable for the use of man or beast. They are particularly obnoxious around granaries, feed houses, and stores and may do considerable damage in destroying or contaminating food supplies intended for human consumption. In addition they will feed on such animal matter as insects and meat when available.
These mice are exceedingly prolific breeders. As many as 13 litters can be produced in one year. The number of young per litter averages about six. The gestation period is approximately 19 days, varying from 18 to 20. At birth the young mice are nearly naked with their eyes and ears closed. They develop rapidly; at the age of 3 weeks they are fully weaned and at the age of 4 weeks some of the young females are ready to assume family duties, although the average age of sexual maturity is about 35 days in females and 60 days in males. With commensals, breeding occurs throughout the year although it is somewhat curtailed in the colder months. In the wild state breeding appears to be restricted to the period from early June to late fall.
Although these mice are destructive when allowed to run free, they are widely used in laboratories as subjects for biological, genetic, and medical studies. When ranging free, however, they do a considerable amount of damage although they are not nearly so troublesome as the introduced rat.