Rats commonly gnaw on wooden structures, such as wall studs, joists, and door corners. Newer gnaw marks have rougher edges than older ones. Gnawing may be indicated by woodchips around baseboard, doors, basement windows and frames, kitchen cabinets, furniture, clothes, stored materials, around pipes in floors and walls, and wherever rats might try to enlarge a crack or crevice or enter something.
Rats tend to burrow along foundations and walls, and underneath debris or shrubbery.
Rats will run between nesting areas and feeding areas. Depending greatly on their memory, they will use the same path over and over. Outside, you can look for a packed pathway or narrow path in dense vegetation. Inside, rats use walls as guidance. An indoor path can be noticed by greasy or dirty smudge marks along the walls, pipes, beams, and rafters.
Runway markings, "grease marks" can be found along pipes, beams, vertical surfaces, and around rafters. Active runways will not have dust or cobwebs.
Urine stains from rats are visible in a UV black light. You may notice a musky scent.
You may also hear sounds of rodents in your walls, attic, and crawl spaces. If you have pets, they may act excited or upset in the presence of rodents.
If you have any or all of the above signs of a rodent infestation, your next step would be to find, and eliminate their entrance into your home and/or yard.
Start your investigation at the exterior of your home. You want to look for areas that provide food, harborage, and water. For example, wood piles, piles or stacks of refuse, shrubs, birdfeeders, attics, crawl spaces, cupboards, closets, and food storage areas. As for how they enter your home, watch areas around windows, door thresholds, utility lines, rooftops, and downspouts.
Excluding Rodents From Your Yard
All rubbish piles and refuse need to be eliminated
Landscaped areas need to be properly maintained with wood piles elevated off the ground
Garbage cans and dumpsters should have tight fitting lids
Rodents can live off of the spilled and surplus food from bird feeders and pet food
Keeping them out of your house
Check openings under doors, add flashing or appropriate material to close the gap. Remember, rats can enter a space greater than 1/2" and mice a space greater than 1/4".
In spaces created by utilities, gaps around chimneys, gaps under flashing and holes in roof tiles, a metal mesh (such as steel or copper wool) can be used to plug the holes.
Larger holes, such as in attic vents, a wire mesh can be used to prohibit the entrance of rodents.
Now that you have eliminated entrance into your yard and/or your home, it is time to get rid of them.
1. Use plenty of traps. You may need more than you think. Usually the rat population is larger than expected.
2. Choose the correct trap. A mouse trap will not capture a rat.
3. Place traps in areas of high-activity (darkened corner, behind appliances, along walls, and wherever rat feces are found).
4. Place traps approximately 15 to 20 feet apart.
5. Position traps to maximize likelihood of rats to come across it in their natural travels.
6. Placement of unset traps in a new location for a week or two before setting them will increase the chance of trapping. Rats are leery of new objects in their environment.
7. Set out, unset rat traps can be buried in grain, sawdust, or similar materials within an empty cardboard box or pie pan. Place the rat bait in small pieces near it and above it with the hidden trap below. Once the rats start taking the bait, set the traps. This will acclimate the rats to the traps, once acclimated, set enough traps to kill a large percentage of the population before the rodents become "trap shy". This is called mass trapping, trapping them at a higher rate than they can repopulate and become shy of the trap.
Types of Traps
Rat Snap Traps:
Advantages: relatively inexpensive and will instantly kill a rat
Disadvantages: The spring on the rat snap trap is very strong
(it could break a finger); keep it out of reach of
children and your pets.
Advantages: 1. Rat glue traps are safer to use than snap traps
unless the snap traps are place in protective bait
2. Rats are less likely to become "trap shy". The glue
boards have a lower profile so the rat is less
suspicious of the new object.
3. Less costly than snap traps.
4. Glue traps can be used inside in a variety of
Disadvantages: 1. Glue traps need to be kept in a dry and dust free
2. It may be considered inhumane to the rat as the rat
may not die immediately.
ADVANTAGES OF USING RAT TRAPS
1. Poison rodent baits may be dangerous to children and pets.
2. For smaller infestations, rat traps provide quick results.
3. Easier to locate the dead rat for easy disposal.
DISADVANTAGES OF USING RAT TRAPS
1. If the infestation is large and severe, trapping can be very
time consuming and labor intensive.
2. Trapping rat programs are not as cost effective as rodent
3. Some rat traps such as the snap traps can injure people, pets, children, or wildlife if they encounter the trap.
4. Some rat traps such as glue boards are not considered humane.
When to use Rat Traps
Use rat traps when poison baits may pose a potential hazard to children, pets or wildlife.
Use rats traps where rodent baits are not allowed due to the possibility of food contamination.
Use rat traps when rodents exhibit bait shyness.
Use rat traps when dead rodents may create odors.
After trapping the rat
Wear gloves when disposing the rat. On a daily basis, check the traps and replace the traps if needed.
If you are concerned with any health threats from the dead rodent, use a household disinfectant.