Standing by your kitchen window one morning, you notice a gray squirrel in the
yard, busily tucking fallen leaves between his throat and chest. "Ah,
he's making a nest," you think, "isn't that nice". The
squirrel, carefully tending his load, hops over to the tree outside your
window and scrambles up out of sight. But then was that a
"thump" on the roof? The sound of little toenails scrabbling
across the shingles, and oh no! a rustling in the attic! Rushing outside,
you find a neat little hole chewed in the lattice vent in the roof peak.
Your attic has become a squirrel den.
Four squirrel species occur in Maryland - gray squirrel, red squirrel,
flying squirrel and fox squirrel. Gray and flying squirrels are the most
abundant and cause homeowners the most problems.
Gray squirrels are active in the daytime and, therefore, are more readily
observed than the nocturnal flying squirrel. In most other ways, their
habits are similar. Breeding seasons occur in January and June. At these
times, gray squirrels can be seen noisily chasing each other through the
trees. The female bears three or four young, which are dependent on her
for about three months.
Squirrels are associated with mature trees, where they normally find
their food and lodging. Gray squirrels prefer tree cavities for winter
dens and raising young, but will construct leaf nests, 12 - 16" in
diameter built in tree tops, to use in spring and summer. Flying squirrels
use only tree cavities. Their food is primarily acorns, nuts, berries,
fruits, buds, and occasionally fungi, bird eggs or nestlings.
Vocal and animated, gray squirrels play and chase each other, often
barking and chattering. They also scold intruders, such as dogs, cats or
people, from a safe perch. In suburban and urban areas, they become quite
tame and can be approached very closely.
The squirrel's most damaging habit is gnawing entrances into attics. Once
inside, they often use insulation or other materials found in the attic
for nest building. Occasionally, they chew electrical wiring and cause
short circuits and sometimes fires. Less frequently, squirrels mistakenly
end up in the living area of a house. They find their way in through an
open damper in a chimney or travel through the walls to the basement.
Squirrels can also become trapped in chimneys. Nesting in houses is
usually the only problem that flying squirrels cause.
Gray Squirrels raid fruit and nut trees, and occasionally vegetable
gardens. They find flower gardens very attractive, and they eat both
flower bulbs and buds. Tree leaves and twigs may be trimmed from trees for
nest building, and bark gnawed away for reasons unknown.
Squirrels bury nuts and acorns, sometimes in lawns. The problem arises
not from the burying because buried nuts are well hidden. However, when
the nut is retrieved, the squirrel doesn't bother to fill in the hole.
Squirrel populations often build up to high numbers in older residential
areas which have lots of mature trees, particularly oaks. Because their
reproductive rate is so high, live trapping is not usually effective. A
homeowner's best bet is to protect his house by screening openings and
removing access to food sources, such as bird feeders.
Attic louvers, vents, and fan openings should be screened with
one-quarter inch mesh hardware cloth. Window screening is not sturdy
enough to prevent their entering. Eaves should be closed up tightly and
rotten boards replaced. Chimneys should be capped.
Squirrels nearly always enter houses near the roof line. Oftentimes,
they can be denied access to the roof of a house by trimming overhanging
tree branches. All branches within six feet of the roof or walls should be
trimmed. Before considering this approach, bear in mind that squirrels can
easily climb textured surfaces, such as brick or rough-cut siding.
Aluminum siding and smooth, painted surfaces are not so easily scaled.
A yard can be made less attractive to squirrels by removing as many
food sources as possible. This means no bird feeding or using
squirrel-proof feeders. A number of squirrel guards for feeders and
squirrel-proof bird feeders are on the market. Check hardware and garden
stores and wildlife-oriented catalogs to see what is available. One method
for protecting feeders mounted on a single post is a cone-shape sheet
metal guard. For this guard to be effective, the feeder must be at least 5
feet above the ground and placed so that squirrels can't jump on it from
Fallen acorns and other nuts can be raked up and removed from small
yards. This removes one source of attraction and reduces the problem of
squirrels digging in the lawn. They usually will not carry acorns very far
to bury them.
The arsenal of weapons for controlling an onslaught of squirrels is
varied, but the best may be your own inventiveness. The following
information will help you plan your attack. Keep in mind, however, that
trapping to reduce populations is generally not effective and poisoning is
Squirrels which have entered attics can often be chased out with a
broom and the entrance closed. When the den area is inaccessible, trapping
is about the only alternative. The live trap should be placed as close as
possible to the squirrel's entranceway. Peanut butter is a very good bait.
When removing squirrels from January through early September, remember
that young may be in the nest. If you have access to a nest with young,
put the whole nest in a box and put it outside near the entrance in a safe
place. The mother will take them to a new location.
Squirrels which have found their way into the living area of a house
can usually be encouraged to leave by darkening the room and opening a
door or window to the outside. It may take an hour or two for the squirrel
to get up enough nerve to leave. A squirrel trapped in a chimney can free
himself if a rope is hung inside the chimney from the top.
Keeping squirrels out of fruit and nut trees is a difficult task. Tall
fruit and nut trees can be protected by trimming away lower branches that
come within six feet of the ground and then placing an 18" long sheet
metal cylinder around the trunk. The top of the cylinder should be about
four and one-half feet above the ground. Groves of dwarf trees can be
protected by an electric fence of the type used for livestock. Place three
or four strands at 4" intervals on metal, not wooden, stakes.
A number of methods can be used to protect flower gardens. The most
effective method for protecting flower bulbs and preventing digging in
gardens is placing one inch mesh chicken wire over the bed before bulbs
sprout in the spring. The flower shoots will easily find their way through
the mesh. A number of commercial repellents are on the market which claim
to repel squirrels from flower beds and shrubs. They are available at
hardware and garden stores.
Squirrel's twig-trimming and bark gnawing activities usually do not do
long-lasting damage to trees. Large patches where the bark has been
removed should be coated with a tree-pruning paint.
In general, squirrels carry no diseases that are easily transmitted to
humans. It is subject to rabies; however, rabies in squirrels is very
rare. Any squirrel that is exceedingly aggressive, lethargic, has trouble
moving, or is immobile should be avoided.
Maryland Department of Natural Resources
Wildlife and Heritage Service
Tawes State Office Building, E-1
Annapolis MD 21401
Toll-free in Maryland: 1-877-620-8DNR, Ext. 8540
Photo of Squirrell Bird Feeder
Courtesy of GustavoG, flickr
580 Taylor Ave, Annapolis MD 21401