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Pests & Wildlife

Pests & Wildlife

Rats

Rats are a never-ending problem in the Pacific Northwest and keep us busy year-round.  The two most common rats found in Oregon and Southwest Washington are Norway Rats and Roof Rats (see descriptions below).  Both are drawn to the warmth, water, and food sources that our homes and properties offer.  They are both nesters and rapid breeders, which can cause serious problems if not detected early.

Behavior

 

Norway Rats

Norway rats are the larger of the two species.  Adults can reach 10 -12 inches in body size (not including tail) and weigh over a pound.   Their shaggy fur can range from a reddish brown color to dark gray.  The ears and tail are covered in scales with the length of the tail being slightly shorter than the length of the body. Their droppings are 1/2" - 3/4" long and are capsule-sized with blunt ends.

 

Norway Rats are great burrowers. Despite the size of their bodies, they can fit through holes as small as 1" in diameter.  In the wild, they build their nests in underground boroughs and then travel from the nest to seek food and water. However, once they gain access to a home, building, or structure, they are known to build their nests inside attics and crawlspaces, as well as walls and sewers.

 

While all rats are amazing reproducers, the Norway Rat is particularly hard to control.  Females reach sexual maturity within 2 to 5 months and can breed any month of the year, producing between 3 to 12 litters per year. Each litter can number from 4 to 22 babies. 

 

Average life span of the Norway Rat in the wild is about 1 year.

 

Roof Rats

Roof rats are slightly smaller and have sleeker bodies reaching up to 8 inches (not including tail) and weighing up to 1 pound.  Their fur is smooth and dark brown to black in color.  They have large eyes and a pointed nose. Roof Rat droppings can be distinguished from Norway Rats. They are 1/4 - 1/2" in length and capsule shape with pointy ends.

Roof Rats are great climbers and can often be found in the higher places within structures, as well as in the walls and crawlspaces.

Roof Rats are also ambitious breeders and, just like the Norway Rat, become sexually mature within 2 to 5 months after birth.  The Roof Rat produces 4 to 6 litters per year that consist of 6 to 8 young each. Life span in the wild is about one year.

Prevention

 

How Do You Know When You Have Rats?

Rats will seldom make themselves visible in open daylight.  If you do see them, it usually indicates that their nests have been taken over by other rats or disturbed by natural or man-made causes.  Unless you have a major problem, you are more likely to confirm a rat infestation through the following:
  • Odorous smells, like ammonia, coming through your floors, walls, and exposed areas.
  • Crawling sounds through your walls at night.
  • Gnaw marks on food, utility lines, and other exposed areas.
  • Grease stains along their footpaths and low-lying areas of your structure.
  • Fecal trails (view descriptions above).

When you confirm that you have a rat or other rodent problem, call a professional.  Rat problems can get out of control quickly.

 

Prevention

It is a common misconception that you can simply eliminate rats with traps and bait. While these can are effective for extermination purposes, they do not address the circumstances that attracted the rats in the first place, nor to they close off the access points that allowed them to gain access to your home or property.  While long-term prevention usually involves the help of a professional, here are a few tips to help keep rats from being interested in your structure.

  1. Avoid having bird feeders, or at least having them close to the vulnerable places in your property.  Rats easily get access to the feed and then look for a safe, warm place to store it.  FYI, chicken coops are one of the main rat attractions in the Northwest. If you have a chicken coop, you can expect rats to come with it.
  2. Frequently inspect the access points to your home.  This includes windows, screens, garage doors, doorway entrances, laundry vents, exhaust fans, and many others.  Look for small holes, loose, thin or crumbled concrete, and compromised wood structures.  Remember, a rat can fit through any hole it can squeeze its head into.  If you find small holes or compromised areas, have them sealed permanently and professionally.
  3. Keep trees, tree limbs, shrubs, and other growing things trimmed and away from your house or property.  Rats can use these to reach the higher access areas of your structure.
  4. Check the foundation of your property frequently.  Rats (especially Norway Rats) are incredible buroughers.  If you have a shallow foundation, they can dig down and get underneath it.