A.This is a million-dollar
question without (unfortunately) a million-dollar
answer. Effective rodent management is based on
exclusion — you have to keep them out.
Killing rodents once they have entered the
structure doesn't solve the problem, because there
are always more rodents to take their places. Also,
killing rodents with poison bait inside insulation
causes other problems: When they die, they decay
and smell really bad! Plus, they attract insects
and other decomposers.
Keeping mice out is a big challenge. They can
enter a gap that's only 1/4 inch in diameter. But
control is not hopeless. Mice begin to enter homes
in search of food and shelter during the early fall
when the weather turns colder. Establishing an
active trapping effort around the outside of the
home during this time will pay big dividends. Tight
construction is also essential. Mice can climb
well, so be especially careful to identify and seal
all gaps in the construction within 3 feet of
grade. Don't ignore gaps in the roof construction,
either. Look specifically for plumbing and
electrical penetrations, spaces under doors,
basement floor drains, and other construction gaps.
Fill all gaps with inedible materials like sheet
metal, hardware cloth, wire mesh, cement, or
plaster. Mice can easily chew through most
construction foams and caulks.
It's important to make the area around the house
unattractive to nesting mice as well. Remove thick
vegetation, piles of junk or clutter, bird-feeder
droppings (and other mouse food), and any debris
from the area surrounding the home. With a little
luck and effort, you should be able to keep your
rodent roommates to a bare minimum.
Paul Fisette is director of
Building Materials and Wood Technology at the
University of Massachusetts at Amherst and a JLC