Salem's rodent profile is shaped by two underappreciated factors: the age of the housing stock east of the Willamette, and the daytime swing in human density driven by state government. Roughly 30,000 state workers commute in each weekday. The downtown food service that supports them runs a steady commercial-grade Norway rat pressure on Court Street, State Street, and the blocks immediately north of the capitol.
NE Salem and the older grid.
The neighborhoods between the Willamette and 25th Street NE — Northgate, Highland, Lansing, Grant — are dominated by pre-1950 housing. Same rim-joist and crawl-vent pattern as inner SE Portland, with a slightly drier overall climate. Norway rats use the same building-stock vulnerabilities; the local twist is that the slough and creek network in NE Salem (Mill Creek, Pringle Creek's eastern reach) maintains a baseline population that doesn't seasonally collapse the way drier-area populations do.
Salem's rodent year is steadier than Portland's. The peaks are softer, but so are the off-seasons — there is no real summer reprieve here.
West Salem and Keizer.
West Salem (Polk County) and Keizer (north Marion) are newer housing stock with different vulnerabilities — primarily garage-door thresholds, gas service entries, and attic-vent louvers on mid-century ranches. The rodent profile is also somewhat different: lower Norway rat, higher house mouse, and more deer-mouse pressure where the city limits abut the foothills west of West Salem.
The downtown commercial corridor.
State Street, Court Street, and the Liberty / Commercial Street downtown core run a permanent commercial-grade Norway rat pressure, sustained by the food service that supports the capitol and downtown offices. Residential properties within four blocks of the corridor field meaningfully higher call volumes than properties farther out.
What to do before an operator arrives.
Same standard walk-around — exterior holes, gas service entries, dryer vents, downspout-to-foundation gaps. The Salem-specific addition: check your gas-meter side. The gas service entries in pre-1950 NE Salem homes are a common ingress and a common miss.