all have our limits on what we will and won’t tolerate
when it comes to pests in the home and garden, but there
are good reasons to control rodent populations, says
Contra Costa Master Gardener Steve Griffin.
— rats, mice, moles, gophers, tree squirrels and
ground squirrels — can cause damage to infrastructure
and spread diseases.
are some of Griffin’s tips on keeping them from
becoming too much of a pest.
first step is to identify what type of rodent problem
you have. Knowing what animal is eating your plants,
digging holes in your yard or snacking on food in the
kitchen will determine what steps you take to control
a good look at your home and yard. Are you inviting the
pests in by leaving pet food out, feeding the birds or
having fruit trees?
look at changes you can make to discourage rodents from
visiting. You may need to start storing food in
containers, removing food after pets have eaten, and
pruning trees away from your home to prevent rodents
from climbing onto your roof and into your attic.
up entryways into your home also will help eliminate the
problems inside, Griffin says. Outside, look at fencing
and other exclusions.
you decide to take lethal steps to control rodents,
choose your tools carefully. Never use poisons, which
often unintentionally kill other animals.
you use traps that capture animals alive, you’ll have
to release them on your own property — it is against
the law to relocate them without a permit from state
officials, which is seldom given — or humanely kill
are two species of rats — roof rats and Norway rats
— that live with humans, and we have both in the Bay
rats usually are found on the ground floor. They have
heavier bodies and tails that are shorter than the
length of their bodies.
rats prefer trash and wood piles, and basements.
rats are great climbers and usually are found in the
home, attic and garden. They are smaller than Norway
rats and have a tail that is longer than their bodies.
rats are agile climbers and nest above ground in trees,
walls, cabinets and false ceilings.
populations rise and fall with the availability of food
and weather conditions.
mice are attracted to pet food, snacks left in drawers
and pantries with plenty of food in cardboard or light
will nest in walls, drawers and cabinets, and build
nests of almost any materials the can find.
and mice spread disease through fleas, feces and urine,
which they leave behind on their searches for food.
housekeeping can keep most rat and mouse populations
down. Repair door sweeps, plug entry holes, screen attic
vents and the vents around building foundations. Trim
limbs and landscaping away from the roof line and
foundation walls. Pick up pet food and seal food in
sturdy plastic or metal containers.
mice and rats with snap or electronic traps. Do not use
a rat trap with nuts or sticky candy tied to the trigger
with twist-ties, wire or zip ties. Bait a mouse trap
with peanut butter or a soft candy such as caramel.
live most of their lives underground, feeding on roots
and tubers. They occasionally come out of their burrows
at night to feed on plants, fruit and vegetables.
are not good climbers, so any vegetables that are low to
the ground are targeted.
know if you have a gopher, look for crescent shaped
mounds of soil with a plugged hole. The tunnel radiates
out from the crescent and angles down about a foot.
are solitary animals except for mating. Usually only one
gopher will be found in a yard, and gophers will fight
off other gophers for territory. Just because you see
multiple mounds doesn’t mean you have many gophers.
are the best control for gophers, but not everyone has
an owl nearby. You’ll probably have to resort to
exclusion and trapping.
a wire mesh under raised beds; bury the mesh —
hardware cloth — 24 inches down to create a barrier
around your yard or garden. Pair the underground fence
with an above ground one.
you choose to trap, practice setting it before you try
placing it. There are many types of traps that are
effective in killing gophers.
the right spot to trap is the key to success, Griffin
says. Knock down all the old mounds and keep watch for a
new one to appear. Dig out the mound and find the main
tunnel below and leading away from the mound. Set two
traps in the tunnel, facing each other, so the gopher
will be trapped whether it is coming or going. Secure
the trap and then place cardboard or plywood over the
hole, covered lightly with soil. Wait a couple of days,
then check the traps.
are insectivores and don’t eat plant material. Any
damage they do is to the appearance of your garden or
yard, and occasionally they may kill a plant when they
disturb the soil around plant roots.
are difficult to capture and probably should just be
can bury mesh, as you do with gophers, to exclude moles
from the yard. Trapping rarely works.
mouselike creatures hardly ever enter dwellings, but
they can do some damage in the garden and landscape.
Their populations rise and fall with great regularity.
are active day and night, feeding on grasses, veggies,
bulbs, roots and tree bark. Unchecked, they can girdle a
young tree and kill it by eating the bark through the
young trees with a guard at the base and keep ground
covers away from the tree trunk.
with unbaited mouse traps, placed in the pathways of the
squirrels can be a nuisance, feeding on fruit and
vegetables, and nesting in attics. They also can vector
diseases through fleas.
squirrels are extremely destructive, digging under
roads, fences, foundations and utilities. They feed on
vegetables and can destroy a garden in a short time.
squirrels dig large dens with open holes. They also
vector diseases through fleas.
ground squirrels with wire fences, above and below
ground, and with an electric shock wire along the top of
squirrels can be trapped and killed at any time; most
tree squirrels are protected and can be taken only
during hunting season, with a license. The Eastern fox
squirrel can be taken at any time without special
coyotes, foxes and bobcats feed on ground squirrels, so
don’t use poisons as a method of controlling the
and deterrents are the best ways of handling any pest