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Fall kicks off a season of beauty in Lake Oswego, but the transition from summer to fall and winter is also the beginning of another season. Rat season. Ew.

Rats are year round pests in Lake Oswego, but as the weather cools the rodents may begin to seek shelter indoors or in comfortable outdoor nesting places near homes. Around this time of  year our office begins to receive a high volume of phone calls regarding rat problems in Lake Oswego.

Knowing how to deter rats as well as recognize the presence of rats is the first step to tackling a potential rat problem.

What are the signs of a rat problem?

Aside from actually seeing the pests, many people realize that they have a rat problem when they begin to notice rat droppings, smudge marks from the oil of a rat body on walls, signs that rats have come into contact with food items like torn packaging, gnaw markings on walls, doors or furniture, or the discovery of a rat nest. Sometimes a rat problem is identified when a household pet begins to stare intensely at a wall or a home resident notices mysterious sounds coming from within a wall.

Will the City of Lake Oswego respond to rat problems?

Lake Oswego does not complete any requests regarding above ground rodents. That said, the city does encourage local residents to report any sightings of rodents, including rats coming out of the local sewer system or out of resident’s plumbing fixtures. The City of Lake Oswego asks residents to call the Public Works Maintenance line at 503-635-0280 and provide a specific location of the concern. The city will respond by baiting nearby manholes if applicable.

What does the City of Lake Oswego recommend to control rats near the home?

To assist with rat control near your home, the city recommends basic measures to ensure that potential food and shelter sources are not made available to rats.

These measures might include covering garbage cans with tight metal covers, storing dog & cat food, rabbit food, etc in rat proof containers, not allowing fruit from fruit trees to be left in the yard, keeping dog bones out of the yard, and keeping rabbit hutches at least a foot off the ground.

In terms of nesting sites, the City of Lake Oswego recommends removing brush piles from the yard, covering vents with screens, repairing any holes and cracks in the foundation of your home, and keeping wood piles at least a foot off of the ground.

Additional local factors that often lead to rat infestations

As pest professionals in Lake Oswego and surrounding areas, we routinely observe several factors that can be underlying causes of rat infestations. These include:

  • The presence of chicken coops on the property or on an adjacent property is a major contributing factor
  • Bird feeders on the property or on adjacent properties, especially when the bird seed falls to the ground
  • Trash build-up on the property or on adjacent properties
  • Vegetation overgrowth or other harborage sites such as woodpiles and large amounts of clutter
  • Decks and sheds that have voids underneath that are mostly inaccessible to humans but big enough for rats to fit inside
  • Blackberry berry bushes which provide both harborage and a food source to rats
  • Tree limbs touching the roof or siding of a home
  • Openings around the outside of the home at least as big as a quarter, e.g., crawl space vents that have been breached, gaps around pipes, gaps in garage door seals, etc.

Will a cat help with a rat problem?

Not usually. A recent study conducted by researchers at Fordham University found that cats are surprisingly bad at killing rats. Over the course of the 79-day testing period, local cats ambushed just three of the facility’s roughly 150 rats—killing only two.

While a cat may kill a young or small rat, a cat is usually deterred from rat hunting after one run in with an adult rat! It’s usually best to seek other options for rat control.

Are rats dangerous?

There are a number of dangers associated with rats which can include both damage to a home and the spread of disease.

Since rats front teeth grow continually over the course of their lives, rats will gnaw on things to keep their teeth trimmed down. Rats can gnaw through electrical wiring, causing electrical issues and potential fire hazards.

Rats are also a danger to public health. Rats carry diseases that are harmful to humans and pets. According to some, rats are the carriers of more potentially lethal diseases than any other animal. These diseases include salmonella, bubonic and pneumonic plague, murine typhus, and leptospirosis among many others. Diseases can be spread to humans through the handling of live or dead rats, through contact with a rat’s body fluids, through contact with fleas, and through rat bites.

What should I do if I expect a rat infestation?

Treating for a rat problem is a multi-step process that first involves identifying entry points and then trapping and/or baiting to remove the rats. Although it may seem counterintuitive at first, the third step involves sealing up points of entry.  This is because it’s important to allow rats a chance to leave a home or business to die during the baiting process.

The first step is to do everything possible to identify the specific location of the infestation and thoroughly bait and/or trap all existing rats. It’s important to note that rats are very smart and they are suspicious of new additions or any changes to their surroundings.They may notice a trap and/or the new food (rodenticide) and become wary. Don’t let this discourage you. It’s common for this process to take several days and sometimes weeks.

After the location has been identified and the treatment has been performed, it’s important to follow up and seal points of entry. While it may not always be possible to “rodent proof” a home, it’s vital to cut of the paths of least resistance and do everything possible to eliminate a rat’s physical access to the structure.

Any opening greater than 5/8 of an inch or about the size of a quarter should be sealed. Interior holes should generally be filled with stainless steel fibers. A good weather proof mesh will stop the rat from reopening the hole. For bigger holes around the outside of a structure, it may occasionally be necessary for a licensed contractor to do the repair.

Trapping rats can be a good and fast solution if the rat problem is not a large one. Rat traps can be purchased inexpensively at stores like Lake Oswego Ace Hardware or Home Depot. It’s usually a good idea to purchase more than you think that you’ll need as a rat colony is often larger than anticipated. Place the traps along walls about 10-15 ft apart as rats prefer to run along walls in an attempt to be undetected. Don’t touch household pets before touching the traps. Some people prefer trapping because they can physically see the rat and remove it from the home before it begins to decompose and smell. Continue trapping for at least a full week.

Baiting rats can be the right solution if the rat colony is large or if the size of the colony is unknown. There are products known as “bait stations” which help to protect kids and animals from accessing the poison. As with the traps, place the bait stations 10-15 feet apart in an area where you suspect high rat activity.  Bait stations can also be a very effective means to prevent reinfestation. Sometimes homeowners find it easier to hire a licensed exterminator to handle the baiting and rat removal processes in a way that is both safe and effective.

How do I clean up following a rat infestation?

Rats are incredibly unsanitary, so it’s very important to clean up their nesting areas and dispose of dead rats appropriately.

The Centers for Disease Control and Prevention have specific guidelines on how to clean up after rats. The CDC recommends wearing long rubber, latex, or vinyl gloves, and spraying the nesting area (including the carcass) with a mixture of bleach and water. Let the solution soak for at least 5 minutes before mopping up. Place the dead rodent and the nesting materials in a thick plastic bag and then double bag. Place the bag in a sealed garbage can that is regularly emptied.  

Who can I call to address a rat problem in Lake Oswego?

If you’re currently experiencing a rat problem at your home or business, you’re not alone! Rats are a common problem and a major concern for many Lake Oswego residents.  Aspen Pest Control loves serving our Lake Oswego community including family homes and businesses. We have successfully treated many homes in Lake Oswego for rats. We offer free, no pressure estimates and same day service for no extra charge. Our results are 100% guaranteed and we use products that are safe for your family and pets. Contact us to discover why your neighbors in Lake Oswego are loyal customers of Aspen Pest Control.