Why Portland Rat Control Can Actually Be Green

by | Mar 21, 2021 | Pest, Rodent Control

In Portland rat control is incredibly important. We have a multitude of gardens, aging garages and old homes that are totally vulnerable to city rats. This article describes why ignoring rats might create more problems for the environment later, and what we can do avoid rats naturally.

Portland Rat Control is Invasive Species Control

It’s important to recognize that rats, particularly Norway and roof rats, didn’t naturally belong in Portland’s ecosystem. 

Norway rats and roof rats are introduced by humans in sensitive habitats across the globe, so they’re technically an invasive species. They exist because we exist.

Before either Norway or roof rats were introduced, native rats lived here.

Native Rodents of Portland OR

What native rodent species originally scurried through native bunchgrass prairies and oak savannas of the land occupied called Portland?

Native rats include bushy tailed woodrat (Neotoma cinerea) and dusky footed woodrat (Neotoma fuscipes).

Portland native mice are deer mouse (Peromyscus maniculatus), Pacific jumping mouse (Zapus trinotatus), and Townsend’s vole (Microtus townsendii).

The red tree vole (Phenacomys longicaudus) lived in conifer forests and nibbled almost exclusively on Douglas fir needles. They are now relatively rare but can be seen in this amazing video.

For the most part all these small rodent species are long gone from the land we call Portland.

Even the chipmunks (Tamias townsendii), have been pushed out of Portland by more aggressive invasive rodents like rats.


Portland Rat Control.

Pest Rodents

Now the only rodents common in Portland are invasive “pests”. Particularly, Norway rats (Rattus norvegicus) and Roof rats (Rattus rattus).

House mice (Mus musculus) aren’t even common in Portland OR because rats are predators of mice.

Portland Rat Problem

If you’ve heard about the Portland rat problem, there’s a reason.

Norway rats & roof rats are non-native, “commensal” pest species. Commensal means “at the table,” and refers to rats and mice’s dependence on humans for basic survival. Rats rose to this status of notoriety over thousands of years by self-domesticating themselves for the food and habitat that we unknowingly and unthinkingly provide.

Another term for species that live alongside humans is “synanthropic”.

Norway & roof rats are no doubt a nuisance. They contaminate food storage. They destroy car wiring. Rats can start electrical fires. They foul up homes & business with urine and droppings. 

Portland rats make noise and nest in our walls, attics, and crawlspaces at night. Also they make large unsightly burrow holes in our gardens and backyards.

Close up of small Norway rat feeding on bird seeds

Rat Pest Control Challenges

When discussing invasive species we should recognize that humans ourselves are the greatest. Indeed we’re the premier contributor to habitat degradation and biodiversity loss. Undoubtedly there’s major issues today. So while we blame Norway rats and house mice for habitat degradation, it’d be poor taste not to note our role in creating big sticky ecological messes.

Commensal rodents’ ability to so precisely adapt to the crevices of human habitats over centuries is an incredible evolutionary strategy for survival. They rival us in their resourcefulness to carry out their destructive behaviors.


dusky footed wood rat nest

A dusky footed wood rat nest can be several feet high, and lined with pest-controlling bay leaves


Portland Rat Control for Native Rodent Conservation

Norway rats likely originated from northeast Asia, roof rats from southeast Asia and house mice from the Indian subcontinent. They’re not just problems for humans, they harm the ecosystem too. By being more aggressive, invasive rat species have mostly overtaken our native rat, mouse and vole species in the Portland area.

Take the dusky footed wood rat. This endemic rat species builds towering wooden nests up to three feet high which are critical habitat for smaller critters when abandoned.

Sometimes dusky footed wood rats even line their nests with bits bay laurel to keep pathogenic insects and mites away. These native rats do their own pest control!

But dusky footed wood rats could not adapt to human habitat like Norway or roof rats. So they could not compete for the same land once white settler-colonist developments moved in. 

Choosing to be Proactive About Rats

We should all do our part to control Norway and roof rats, in the hopes that native rodent species might be able to return to some of their ancestral habitat in Portland

Many Portland homeowners choose not to control rats with rodenticides to prevent pollution and protect wildlife. But sometimes well-meaning people need to call an exterminator–and out the poison goes. So if we value reducing pesticide usage, we should always use Integrated Pest Management for rats to prevent them from reproducing in the first place:


Eco-Friendly Rat Control.   

Eco-friendly Portland Rat Control

For the greenest Portland rat control, remember to remove any exterior food sources.

  • It is recommended never to feed wildlife, especially in Portland where rats are more of an economic & environmental issue than we may realize.
  • The best way to support birds, pollinators, and other wildlife is by planting native plant species, which provides them with natural habitat & food sources.
  • Native plants also support natural pest control mechanisms, biodiversity and overall sustainability.
  • Limit rat nesting & hiding places by removing low-lying vegetation and overgrowth within one foot of the ground, fence lines, and sides of buildings.
  • Keep 1-2 rat traps set in your crawlspace, attic, outbuildings or garage out of reach of pets & children to monitor for interior activity.

If you’ve tried a few things and need help creating a custom Integrated Pest Management (IPM) strategy for Portland rat control, feel free to call.

pest and pollinator logo with phone number and contact info