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By Cheryl K. Smith – We’re not the only ones that want to spend our time indoors. Rats, mice, skunks, and other furry interlopers are busy finding their way into houses across the country and setting up housekeeping. They are also interested in cabins and other buildings that are closed up and unused during the colder months of the year. Now is the time to learn how to repel rats and other interlopers.

Sharing living quarters with these trespassers can be an annoying, destructive and unhealthy experience. Being nocturnal, these critters are busiest at night, as they go about finding food, gnawing and scratching at walls, or just running around. Anyone who has ever had a rat or rodent in their attic or wall knows what I’m talking about.

These pesky creatures will attempt to create new passes or widen those that already exist, chew up valuables, and contaminate food. They will store food throughout the house. They will multiply quickly, adding to the problems they have already created.

The damage caused by these critters goes beyond annoying and unsanitary. They can not only gnaw on walls but can chew through electrical wires, even leading to house fires. Different mammal trespassers present different problems, so they require a variety of strategies for prevention and removal.

Common Problem Animals

Rats

Several kinds of rats can wreak havoc in a home. These include the Norway rat, the Roof rat, the Wood rat (also known as pack rat, because of its propensity for collecting and storing items) and the Black rat. The Norway Rat is the most common of house rats and is found all over the world.

The first thing you need to know about how to repel rats is what attracts them. Although rats will eat anything, they are particularly fond of dog food, fish, meat, and cereal. They also are extremely destructive, and have even been known to chew through plastic and lead pipes. They need only a half-inch opening to get into a structure.

Mice

Mice are similar to rats, only smaller. The same tactics you learn for how to get rid of rats can also be used for mice. One key to determining whether a house is infested with mice or rats is to check their droppings. The droppings of mice are much smaller than those of rats.

Unlike rats, which eat a lot at one time, mice are nibblers. They also like quiet nesting places, which they line with insulation, cloth, and shredded paper.

Male mice are territorial and mark that territory with urine. They need only a 1/4-inch opening to get into a structure.

Mice and rats multiply rapidly, contaminate food and food-storing surfaces with their urine and droppings, harbor fleas and mites that can infest the house and family pets, and carry disease. Hantavirus is spread by mice, particularly in the southwest U.S. and bubonic plague is carried by the fleas that infest some rats.

Skunks and Opossums

Most people rarely encounter skunks or opossums, other than as road kill. However, these nocturnal animals have been known to make their sleeping quarters under houses or in crawl spaces. Skunks may be striped or spotted, and are members of the weasel family. They are a nuisance, mostly because of the foul odor they expel when frightened or excited. On the other hand, skunks eat rats, mice, and other rodents, so at least a skunk is one answer to how to repel rats.

Opossums are foul-smelling, unattractive animals that like dog food and road kill. Interestingly, they are resistant to rabies but are known to carry protozoal myeloencephalitis, a disease that is fatal to horses. Because of this, extra care should be taken to keep them away from horse barns.

Bats

The bat is another creature that can both help and hinder humans. Because they eat mosquitoes and other bugs, they are essential to the ecosystem. They are not good roommates because of the urine and droppings they leave during their residence in attics and walls. Like skunks, they also are known to carry rabies and, in fact, are responsible for the majority of human rabies cases. During the winter months, bats that don’t migrate to a warmer climate will hibernate. If the colony is not large or noisy, some people never even know they are there or will allow them to stay in the attic or wall.

Squirrels

Squirrels, like other mammals, need a cozy place to nest and to give birth to their young. Attics and walls often fit the bill. While not known as serious disease carriers, they can be destructive and a nuisance.

Raccoons

Raccoons sometimes will move into the attic or chimney of a house. They have sharp claws and can cause a lot of structural damage. Like squirrels, they are usually more of a nuisance than anything else.

Preparation and Prevention

The first step to learning how to repel rats and other interlopers is a little advance annual prevention. This can help to prevent unwanted creatures from moving in and sharing your living space. A good strategy is to try to think like the interlopers. Investigate the building you want to protect, looking for cracks and holes that look hospitable. Look in particular at the bottom and the top of the house.

For burrowing animals, adding wire to the bottom of the house is a good solution. Make sure to actually go into the ground with the wire. Remember that even a ¼-inch space may allow access. Attaching lattice around the bottom of a deck is helpful in keeping large animals out. Check for trails that lead to any entrance and patch holes. Double-check any lattice that was previously installed to ensure that these critters haven’t broken through in preparation for the winter.

A common entryway for animals is through the garage. They may start out by moving into the shelter made available by an open garage door and then, over time, gnaw their way into the walls or the home itself. One way to help prevent this is to avoid storing unused or summer items along walls that abut the house, so you don’t provide a cover for their activities as they work their way into the warmer house. Another is to annually organize the garage, discarding or recycling items that you no longer need.

Make sure that all holes to the outside or to the walls are covered or filled with mesh hardware cloth or something similarly strong. Some people have had luck filling holes with steel wool and then spraying in foam insulation to keep it in place. This method will last for a few years but has to be redone regularly, as rodents chew it away over time.

Attics are notorious for sheltering invading animals. Inspect the attic thoroughly for animal droppings (wearing a mask or respirator) and holes or other entryways where they can get in. Screen off trouble areas.

Remove overhanging branches and other vegetation to deter rooftop entry by squirrels and other climbing animals. Some experts recommend cementing pieces of glass along the edges of the roof to deter animals from coming onto the roof at all.

Look at cupboards and drawers indoors, especially where there is a history of rodent occupation. If necessary, purchase new plastic containers for foodstuffs. Trap any mice that may already have made themselves at home and clean the area well with bleach. Get a cat or two, if feasible, to help keep the outdoor rodent population down.

Store animal feed in the barn or other areas in stainless steel garbage cans to discourage access. Rats will chew through plastic garbage cans over time, particularly when they are located in an area that is out of the way and not checked regularly.

Eliminate brush piles or other junk near the house. Elevate woodpiles to make them less hospitable. Put up bat houses in areas where bats are prevalent. Clean gutters. Double-check the chimney and screen it, if necessary.

Eliminating Critters In Residence

Sometimes the first sign that there is an opening into or underneath the house is the animal itself. In that case, make sure to get rid of it before making repairs. Don’t risk discovering (by the smell of decay) that you have trapped an animal in the area you wanted to protect.

These trespassers can be removed in a variety of ways, from live traps to poisons. In some cases, elimination will be simple.

A friend of mine recently had a spotted skunk come into the house through the cat door. This door is located under a deck and enters the bathroom. The skunk had discovered that the cat food was served there. The solution, in this case, was easy: Remove the cat food and block the cat door.

If the offending animal is nocturnal and making forays out at night, close off the opening at that time. Be careful that no babies have been left, though, or the determined mama will dig or scratch in a new entrance to get to them.

With raccoons, skunks, and squirrels, some people have had luck with putting a light in the nesting area when the animal is out at night. This encourages it to stay out because the light makes the area undesirable for sleeping.

Poisoning

Poisoning is a common method of dealing with vermin of all types. It is readily available in supermarkets, drug stores, and farm stores. One problem is that it can be lethal to domestic animals and other animals it wasn’t intended for. Cats or other dogs may either ingest the poison or happen upon the body of an intruder that ate the poison. Another downside to this method is that even when the offending animal eats the poison, it may crawl into a wall and die, causing an offensive smell for a long time as it decays.

Various forms of poison bait are available on the market for those who decide to take this route. These include blocks, pellets, and seeds. Each rodent population is different in their preferences, so trying a little of each may be necessary before the animals are permanently eliminated. Try not to disturb the original habitat, or the rodent may move to another area. Continue to clean and sanitize the area where the poison is located and don’t forget to remove other food sources.

Kill Trapping

Kill traps are another option for how to repel rats and other interlopers. There are electronic, snap or glue traps to choose from. Electronic traps are made to kill rats and mice. They run on batteries and deliver a lethal jolt of electricity to a rodent that has entered.

Snap traps are the common spring-loaded traps that snap shut, killing the mouse or rat when it attempts to get the bait. This mousetrap has been around for a long time—it was invented and patented in 1894 by William Hooker of Illinois. Peanut butter makes the best bait for these traps. To avoid spooking and scaring the rodents away, consider putting unset traps out for a few days before baiting and setting them. The rodents will get used to the traps, even walking on them, and so they theoretically are more likely to feel safe going for the bait the first time it is put out.

Shortcomings of snap traps include that they are messy; rodents can become trap-shy if they set one off without getting injured, and they can be dangerous to children and pets that may get accidentally snapped.

Glue traps, or glue boards, are another method for trapping mice. They have a sticky surface that holds the animal that walks on it when they try to get to the bait. Many people consider these traps inhumane, because the trapped rodents may take a long time to die, frightened and starving to death.

Raising Goats for Dummies mentions a natural way to get rid of mice and rats that was developed in Africa. This solution for how to repel rats and mice consists of a partially buried bucket filled with six inches of water, a corncob and a thick wire. The wire is put through the corncob, and bent and pushed into the ground on each side of the bucket with the cob centered over the bucket. The corncob, which should spin freely, is coated with peanut butter. When the rat or mouse goes after the peanut butter, the cob rotates and the rodent falls into the bucket, ultimately drowning. Sometimes rodents will accidentally drown in livestock water buckets, as well.

Live Trapping

Live traps are the most humane way to remove most invading mammals. They come in a variety of sizes, to enable capturing a range of mammals from small mice to bobcats. They vary in price, depending on their size.

In most cases, people move the captured animal to a distant location after capturing. Be aware that state laws may govern the relocation of certain fur-bearing animals. In some cases, relocated animals have made their way back over many miles to their original location. Spotted skunks, for example, have a 150-mile range, returning to the scene of the crime is not out of the question.

Cleaning Up After Removal

After animal intruders have been removed, thoroughly clean the area where they took up residence. Wear long sleeves and pants, gloves, and a mask or respirator. Gently sweep up the debris or use a vacuum cleaner that has a Hepa filter. Animal droppings can irritate the skin and lungs and, in some cases, cause health problems. Wetting droppings with a sprayer can help minimize breathable dust. Use bleach or another disinfectant to thoroughly clean the area.

Once problem areas are identified, animals removed and the location cleaned, take necessary steps to prevent them from getting in again. When doing the annual pre-winter prevention check of the house, make sure to focus on prior problem areas. These crafty animals know where they succeeded in the past and won’t hesitate to investigate and attempt to get in again.

Trespassing animals can be a nuisance or even a serious safety and health risk. The first line of defense is to prevent them from taking up residence in the first place. Those of us who live near the woods, or in another setting that we share with wildlife, may find it impossible to keep out all interlopers. Taking the necessary steps to prevent them from getting in, remove them when they do move in, and clean up the area when they have been eliminated, can minimize problems.

Trapping & Releasing a Skunk

Items needed:  
• Two sheets or large blankets
• A brick or other object to hold open the trap door
• Leather or canvas gloves

Tips For Keeping Unwelcome Animals Out of Your Home

• Keep your property clean. Remove food, trash, and debris, especially around the house’s foundation.
• Keep trash cans covered tightly.
• Cut back tree branches and other plants that touch or overhang your home or other buildings.
• Stack firewood off the ground; store it away from the house, if feasible.
• Keep bulk pet or livestock feed in closed metal or plastic containers.
• Feed pets indoors or give them only the amount they need for that meal. Dispose of leftovers each night.
• Seal all gaps and entry points.
• Check for and remove or repair structural damage such as dry rot.
• Look for holes where roofs overlap.
• Keep gutters clean.
• Rotate stored items regularly and keep boxes tightly sealed in plastic bags or containers.
• Keep food preparation and storage areas clean and free of crumbs and grease. Use bleach or another disinfectant for cleaning.
• If you have a chimney, consider installing a cap or wire mesh covering to prevent entry.
• Install ¼-inch wire mesh (hardware cloth) over attic, roof and crawl space vents in order to prevent the entry of mammals and birds.
• Provide bat houses for bats.

What would you add to this guide to how to repel rats, mice, skunks & other interlopers?

Cheryl K. Smith is the author of Goat Health Care and Raising Goats for Dummies. She lives in the woods and has had a variety of animals try to take up residence in her home, including opossums, spotted skunks, mice, packrats, and Norwegian rats.

Originally published in the September/October 2011 issue of Countryside & Small Stock Journal  and regularly vetted for accuracy.