RATS and MICE
Get Them Out of Your House and Yard

Michael T. Mengak, Wildlife Specialist

Warnell School of Forestry & Natural Resources

 

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Who Has Rats and Mice?

Every country has rats and mice.  Most rats and mice live in woods and fields, but three species live with people:  the house mouse, Norway rat and roof rat.  All three of these species live in Georgia.  Even in town, rats and mice move in with the best of people.

What Do Rats and Mice Do?
Rats and mice carry diseases, spoil your food, eat your crops, stored grains, birdseed and pet food, and get into your trash.  Their droppings and urine soil your house. Rats and mice can carry fleas and ticks.  They transmit bacteria and diseases like plague.  They are not normally associated with rabies.

Rats and mice are curious. They like open garbage cans, dumpsters, sewers and rubbish heaps.  They eat a variety of foods, including grain and seeds, nuts, meat, candy, processed cereal, fruit, pet food and almost anything else they can find.  They have poor eyesight but excellent senses of smell, taste and touch.  Rats and mice usually hide during the day and come out at night. If you see one, you can be sure there are many more you haven’t seen.  Rats and mice stay near home.  Norway rats may spend their entire lives in an area only 100 to 150 feet in diameter.

What Do Rats and Mice Look Like?
Mice are about 3 inches long, not including the tail.  House mice have a naked tail; native mice have a slightly furry tail.  Rats are much larger – up to a foot long, not including the tail.  Roof rats (Rattus rattus) are also known as black rats or ship rats.  They are sleek and graceful; their ears extend past their eyes. Roof rats are good climbers. They weigh between 5 to 10 ounces, and are brown or black. They are often bred for the pet trade and are intelligent animals. 

Norway rats (Rattus norvegicus) are sometimes called brown rats, house rats, barn rats, sewer rats, gray rats or wharf rats.  Generally, they do not climb.  Norway rats are large and heavy-bodied and can weigh more than 1 pound.  Their ears do not reach past their eyes.  Norway rats have course fur; usually brown or reddish gray. Both Norway rats and roof rats have whitish or gray belly fur.

 

 Prepared by R.Z. Brown, Department of Health, Education and Welfare; Public Health Service, Centers for Disease Control, Atlanta, Georgia

 

Signs You Have Rats or Mice

Droppings:  Mouse droppings are about the size of rice grains; rat droppings are about the size of raisins.

Tracks:  Check for tracks by scattering a small amount of baking flour or talcum powder on the floor along the wall or in likely places like the attic and basement, and behind appliances.  Put a cracker or piece of bread with peanut butter in the center of your tracking patch.  Check for tracks the next day to determine if you have mice or rats.

Burrows:  Check for burrows in weedy places around landscape plants, under boards, under doghouses and near garbage cans or dumpsters.

Gnawings:  A little hole with chewed edges is a sure sign of rodent occupancy.  Check your pantry for chewed packages, shredded paper and tooth marks.

Sound:  Listen for gnawing or scratching in the walls or attics, especially at night.

Nests:  Nests made of chewed paper or cloth (Including gloves, carpet, clothes and rags) are often found in boxes, drawers, toolboxes, basements and attics.

Odor:   A musty, urine-like odor often indicates mice are present, not rats.

Get Rid of Rats and Mice

Rats and mice breed fast.  One pair of breeding mice can potentially lead to millions more in a year, although they do not actually reproduce this quickly in nature. Mice can breed at 30-day intervals, beginning when female mice are only two months old, so you must keep working to get rid of them.  Trapping alone is effective, but to really fight these prolific rodents you should also employ one or more of the following methods:

Take Away Their Food:  Keep garbage in tightly covered cans.  Feed dogs and cats in a dish, take up uneaten food and wash the dish.  A squirrel guard will also deter rats and mice feed from feeding from bird feeders.

Destroy Their Homes:  Remove any places where they can hide and reproduce.  Remove trash, old boards, weeds, brush piles, rock piles, firewood, weeds and other junk from your home, garage and property. Don’t pile wood against the house, and store firewood at least a foot up off the ground.

Close Their Holes and Entranceways:  Mice and rats can enter your house through openings as small as a dime. Closing their entry holes is one of the most effective ways to prevent mice and rats from becoming a pest in your home.  Keep patio and garage doors closed.  Seal the openings under doors.  Cover windows with screens.  One-quarter-inch mesh hardware wire will keep mice and rats outside.  Keep floor drains tightly sealed.  Cement or caulk around pipes (gas, water, hose, air conditioning drains) and wires (phone, cable, TV).  Cover clothes dryer vents (be careful to allow adequate airflow) and clean them regularly to remove lint build-up that could be a fire hazard.  Seal small holes and cracks by stuffing them with steel wool, then caulk over them.  After you get rid of rats and mice, close their burrows with rocks and dirt.  If a burrow is reopened, then you know you still have rats and mice.

What Not To Do:  Sound or flashing lights have almost no effect on repelling rats and mice. Ultrasound devices are almost completely useless in the fight against rodent pests, and commercially available products labeled as “repellents” are generally ineffective.  Taste and odor repellents are not registered for rats and mice.  Homemade products generally do not work either.

Non-native rats and mice are not protected by state laws, but shooting is not generally effective for controlling rats and it may be dangerous and illegal.

Fumigants or gas cartridges should be used only by licensed pest control operators.  Never use fumigants or gas inside structures or dwellings where humans or pets will be exposed.

Traps

Use traps – not poison baits – inside houses.  Poisons are more dangerous to children and pets, and poisoned rodents do not die immediately.  Instead, they usually crawl into an inaccessible space in a wall or behind appliances, die and then smell awful.  Use plenty of traps in rooms, attics, basements and garages.  Put them along the wall, in cupboards and drawers, on countertops and flat surfaces, and in other places where mice might run. Rat traps are larger so place them where children and pets are not likely to accidentally trigger them.  Remember that mice prefer to run along baseboards and walls and do not like to venture out into a room or open space.  Do not expect a mouse to travel more than 5 or 10 feet to find a trap.  Well-fed mice like to stay home and may live for weeks in one corner of your room or attic.  For rats, you can use fewer traps – about a dozen per house should do – but remember that rats are smarter, tougher and harder to catch than mice.

Set your traps with the bait treadle across his path at a right angle to the wall.  Don’t set the trap parallel to the wall.  Make it easy for the rodent to get the bait.  Don’t force it to go around or over your trap to reach the bait.  Using two traps back-to-back – one facing in each direction along the baseboard or wall – is also effective.

Snap traps are easy to set and inexpensive, so use plenty.  Multi-catch traps work fine but are more expensive.  Sticky traps are as good as snap traps for mice but probably will not hold a large rat.  Generally, snap traps can be easily discarded – mouse and all – and you will not have to handle the animal.  Just set a new trap in place of the old one.

Bait:  Mice and rats like peanut butter, bacon, cooked chicken or anything with a strong odor.  Cheese is not necessary. 

Have you caught them all?  It’s hard to say.  Leave the traps in place for a few weeks.

How did rats and mice get into your house?  Discover how and where they got in and seal all the holes. If you are not persistent in finding and sealing all the openings, other mice will find them and get in.  Even strong, tight houses have many holes and small openings that a mouse can use for entrance.

Once you’ve rid your house of mice and rats, can you relax and forget them?  No.  New rodents will find you.  Mice and rats really like to move into warm houses for the winter, so fall is a time when many houses get infested.  Mice will often leave the house in the spring, but don’t be fooled.  You must still trap them and keep the property in good repair.  Save your traps and be ready to start the removal process again.  Keep looking for holes and openings in your house.  Continue to keep the yard and property clean and free of hiding places, and always keep doors closed. 

Poison Baits

Use poison bait outside the house only if you can keep it away from children and pets.  Poison bait tastes good because it often contains sugar as an attractant, so be careful.  A locked shed or garage, attic or wood pile may be suitable.  Cover the bait to protect it from weather. 

Many good poisons are on the market.  Check with your local farm and garden store, hardware store, home improvement store or your local county Extension agent.  Use modern, second-generation poison baits that are fast acting and environmentally safe but not quite as dangerous as quick-kill single dose poisons.  Modern poisons are available as poison food, blocks, pellets or other presentations that are attractive to rats and mice, which need to eat them each day for about a week before they die. 

Do not use homemade chemicals or products not labeled for use as rat and mouse poisons.  Do not use arsenic, mercury, strychnine or other similar products.  Read and follow all label instructions on the poison box or packaging.

Set poison bait stations where you see signs of rodent activity.  Get a sturdy wood, metal or cardboard container.  For rats, cut 3-inch diameter holes in opposite sides of the container at ground level.  You can cut smaller holes for mice.  Fill a small container with a pound of poison bait and put it inside the bait box.  Add bait each day to keep it full.  Don’t let the rodents empty the bait container.  They must feed each day or they will not die.

Use disposable gloves to handle the bait and any dead rodents you find.  Throw them in the garbage or bury them. 

If, after a few weeks, rats and mice are no longer feeding at the bait station, remove the bait.  Save unused bait in clean, tightly sealed, well-labeled containers for later use.  Don’t leave bait out for a long time – two to four weeks should be plenty.  Unattended bait will spoil, mold, or may cause a poisoning accident.

Organize Against Rats and Mice

Get together with your neighbors if you live in a neighborhood or apartment complex that has a rodent problem.  Clean up several yards in the area.  Trap and poison neighborhood rodents at the same time so re-infestation from nearby homes or properties will be less likely.

Remember:  Sanitation is the best method of control.  Trapping is cost-effective, relatively easy and safe, and very effective if done properly.  Always use a dust mask and rubber or disposable gloves when handling mice, rats, traps or poison.  Dispose of dead carcasses and used gloves in the trash or bury them. 

 Attention!!
Pesticide Precautions

1.  Observe all directions, restrictions, precautions and warnings on pesticide labels.  It is a violation of state and federal laws to do otherwise.

2.  Store all pesticides in original containers with labels intact and behind locked doors.  Keep pesticides away from children and pets.

3.  Use pesticides and poisons at the correct labeled dosage and intervals to avoid illegal residues or injury to plants, people or native wildlife.

4.  Apply pesticides carefully to avoid drift or contamination of non-target areas.

5.  Surplus pesticides must be disposed of in accordance with label instructions so contamination of soil, air and water will not result.  Contact the local health department or poison control center for information.

6.  Follow directions on the pesticide label regarding restrictions as required by state and federal laws and regulations.

7.  Avoid any action that may threaten an endangered species or its habitat.  Your county extension office or state wildlife department can provide information on endangered species in your area.  The US Fish and Wildlife Service can assist as well in identifying species or recommending actions that minimize risk to listed species in your area.