Best Rodent Control Means Facing Portland’s Scary Rat Problem

by | Mar 14, 2021 | Pest, Rodent Control

In Portland, we want the best rodent control. But we also want to be careful with poisons and traps. Read on to learn more about Portland’s serious rat problem & get this rat exterminator’s pro-tips for smart rodent control.

Portland Rat Problem

  • The Portland rat problem has slowly been getting worse for over a century.

   Like invasive squirrels, rats expand to new territories and gradually increase numbers and colony sizes over time.

    In Portland rodent removal is in extremely high demand because garbage is abundant and many homes are aging.

Recently Pest & Pollinator was featured on KATU news about rising rat sightings in the Rose City.

Can Rats Learn to Avoid Traps?

Part of what makes Portland’s rat problem challenging is that rats are learning to avoid traps. In extreme cases, they can even learn not to go into bait stations and avoid poison bait.

That’s why it’s important to always follow IPM for rats to prevent rats from reproducing in the first place!


Another issue is neophobia –a trait of Norway & roof rats where they have become afraid anything new in their environment.

Over the decades in Portland we systematically trapped, caught and killed all the curious rats.

Now, the most cautious rats survived and passed those genes along. 

Basically, we’ve accidentally bred super smart rats.

Equipment Avoidance & Disregard (EAD)

Recently pest control professionals have adopted the term “EAD – or Equipment Avoidance & Disregard” to describe rats that simply won’t touch traps, glue boards or even eat poison.


This is a huge problem. If exterminators can’t trap or even poison rats, then aging buildings and any home with a crawlspace becomes completely susceptible to infestations of rats.

  • EAD rodents live in downtown city centers & old buildings that have a long history of rodent control issues.
  • They’re more likely to avoid traps & bait if they have a consistent source of food (ie: dumpsters, food scraps in the sewer).

EAD rodents have been observed in downtown Portland OR.

Rodenticide Resistance

Even if we can get rats to eat posion, they can develop rodenticide resistance. Rats developed resistance to the first generation of anti-coagulant rodenticide– warfarin.

Humans widely overused warfarin in the early 20th century due to its surprisingly low toxicity to larger birds and mammals. Warfarin is actually therapeutic for humans in low doses and is used as blood pressure medication.

But now rat management professionals no longer have access to warfarin as a tool. Our second generation rat poisons are more hazardous if applied incorrectly, and at risk of developing resistance.

Portland Rat Control.

Trapping Rats

So a new breed of neophobic, pesticide resistant rats are lurking in the sewers, underground, and in the dark corners of society. Emerging from the darkness to feed on seeds, nuts, fruits, garbage and whatever.

Neophobic & intelligent, they are smart enough to avoid traps if they see another trapped rodent.

For this reason, traps (of any kind) are only part of the solution.

Do Natural Rat Repellents Work?

Rats have evolved alongside us long enough that they’re used to all the smells we are. 

Things we think of as repellents, rats happily use as food; including garlic, chili, even dog poop.

So natural animal repellents with garlic, chili, peppermint, ultra-sonic devices, or even pet odors & predator urines and other scents that repel rats should only be used temporarily. And as part of a bigger IPM strategy.

Norway, brown or sewer rat feeding on scraps on a sidewalk

Stop Rats Getting in your House

The best way to control rats is to stop them getting in your house.

  • Inspect the foundation and dormers & roofline to find any holes. Then seal any holes well with metal or wood, leaving no gap greater than 1/4″. This is known as rodent exclusion.

If you’re having rodents inside now, consider waiting until they’re under control to seal entry points. Complications from rodent services sometimes come from rodents trapped inside.

Seal Rodent Entry Points

Having a rodent exclusion professional inspect & repair your home will save you time and frustration later. Do not be fooled into thinking that rats won’t return. If there is a hole in your house, it’s only a matter of time before the rats find it.

Make sure your exterminator is looking for entry points and helping you with a plan to seal the house from rodents.

Rat Extermination

Most rat exterminators have their own methods for rat control.

Oftentimes, rodenticide (rat poison) boxes are placed around the exterior of the home. These rodenticide bait stations are put out when rat populations grow to a bothersome size.

Our goal is to maximize trapping as long as it is effective, to prevent using rodenticides at all if necessary.

But whether we like it or not, humans basically use rodenticides to manage urban rats populations to acceptable levels.

Safe Rat Control.   

Why Do We Need Pest Control?

If no one did anything, almost certainly urban rat populations would grow out of control.

  • Rats in sewers & burrows underground can tunnel into homes with dirt crawlspaces and aging construction.
  • They can act as reservoirs for human pathogens. These pathogens could increasingly contaminate kitchen counters and floors of Portland homes without someone calling for rat extermination.
  • Besides invading homes, rats chew car wires and cause significant damage.

Did Covid Cause More Rodents in Portland?

Yes, COVID-19 probably caused an increase of rat activity in residential areas due to restaurant closures.

But even before then, as early as 2013, Portlanders were noticing an uptick of roof rats

How You Can Prevent Portland Rats

Rat prevention is extremely important to avoid issues with rats & diseases.

Remember, Portland exterminators are not able to trap every rat. While we’re asleep, thousands of pounds of rodenticides are gobbled up by hungry Portland rats every month.

To reduce rodenticide usage, we need to follow the steps above to prevent rats from breeding in the first place.

Best Rat Control

It’s important to think of best rat control as a community effort. Rats have an approximately 3 block radius. Low-income neighbors with older homes may be more affected by heavy local rodent populations than folks with newer or better maintained homes.

If you’re interested in getting Integrated Pest Management for Portland rodent control, don’t hesitate to call us. We’re here to help you with the best rodent control options, anticipate & avoid teaching rats to avoid traps, and get you back to live & let live. 








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