When Not To Treat
for Norway Rat
"Don't treat" here mostly means "confirm it's a rat first." A mouse, an attic squirrel, or a misread dropping calls for correct identification before deploying traps or bait, because Norway rat control (ground-level) differs from roof-rat control (elevated). Once an infestation is confirmed in or against a building, delay only lets the colony grow. Source: https://ipm.ucanr.edu/home-and-landscape/rats/