Unfortunately, they are not always killed outright, or at all. If using a trap, use expanded-trigger traps whenever possible. Place traps in areas where they are inaccessible to children and pets. Since rats are sensitive to changes in the environment, traps should be pre-baited. Place baited traps out for several days without setting the trap.
Check traps daily to see if bait is being taken.
Once rats take the bait, add fresh bait and set the trap. Set three traps side by side at right angles to the wall with the triggers facing the wall. Place traps for roof rats on tree limbs, under vegetation, on backyard trellises and fences, and at other above-ground sites. Traps should be inspected daily, and stale baits should be replaced. Chemical Control Options Use poison baits only when trapping and rodent-proofing have failed to solve the problem.