Common Winter Pests and How to Control Them

Winged Carpenter Ant at Rockaway Beach
elisfanclub/Flickr/CC BY-SA 2.0

There's no doubt that summer is prime pest season. Insects are abundant: Flies and mosquitoes buzz freely in through opening doors and windows, and wildlife, including rats and mice, actively roam around grassy lawns and open fields.

But, as many of us learn, pests don't go completely inactive in the winter. In fact, when it is cold and wet or snowy outside, they're even more likely to seek the warmth and shelter of the indoors.

Following are brief descriptions of some of the most common winter pests.

Winged Carpenter Ants

Flying ants in the home are rarely a good sign, and this is particularly true if they are seen indoors during the winter. Finding a winged ant or two indoors during the summer does not necessarily mean there is a problem, but if winged ants are seen in the home during the winter months, there is a strong likelihood that there is a carpenter ant nest inside your house.

Cluster Fly

Homeowners generally expect to swat a fly or two in the house during the summer months. But what is an expected annoyance in the summer can be exasperating in the winter, when doors and windows are sealed tight, and one wouldn't think that any flies are existing in the cold outdoors to come inside.


A wily, curious creature, the house mouse is the most common of home-invading mice. Cute, perhaps, in a cage in the pet store, but not so cute when it decides to make your house its home.


Two species of rodents are most common in the U.S.: the Norway rat and the roof rat. Along with the common house mouse, both rats are believed to have been brought to the U.S. aboard ships bound for the New World in the 17th and 18th centuries.

Bed Bugs

For decades, the saying “Sleep tight, don’t let the bed bugs bite” was a fairly meaningless lights-out phrase for kids. But within the last few years, bed bugs have reappeared, causing sleepless nights for homeowners and hotel owners alike.

Fruit Fly

The fruit fly is one of the most common, and one of the smallest flies found in the home. It is often unknowingly brought into the home on fresh fruits and vegetables.

Moth Fly

Moth flies are a common small fly generally seen buzzing around drains, thus its common name is drain fly. Though it causes no real damage, its high numbers can cause it to become a nuisance pest in or around the home.


There are more than 35,000 known spider species in the world, with only about 3,500 of those appearing in the U.S. and often only one-tenth of those (350) in any single region. In general, spiders are beneficial creatures, preying and feeding on flies, crickets, mites, and other household and yard pests. Most are completely harmless to humans. But when they get into your home, they can definitely be a nuisance.

Overwintering Insects

Any discussion of insects over the winter is likely to elicit the term overwintering. While its meaning can be as simple as indicating how an insect (or other animal or plant) spends its time over the winter, it's more frequently used to refer to a sort of hibernation undertaken by insects in order to survive the cold temperatures.

Firewood Pests

A wood-burning stove or fireplace can bring a great deal of warmth, comfort, and pleasing aesthetics into a home. However, the firewood that is brought inside for that fire can also bring with it a number of household pests.

Preventing Home Invasion

You can prevent a home invasion of pests, and there are methods to control them if they do get in:

  1. Rodent Control: The best method of rodent control is prevention through sanitation and exclusion. These clever creatures can enter a home or building through spaces much smaller than the seeming roundness of their bodies, and they are constantly seeking food, water, and shelter. Thus, it is important to keep an eye out for signs of mice and rats and understand control methods.
  2. Pest Proof Your Home: If you are like most of us, a single cockroach in your home will cause you to pull out a can of bug spray or call a pest control professional.
  3. Get Rid of Ants: To solve an ant problem, you need to first eliminate the ones you don’t see to get rid of the ones you do. Ants are very social insects with very strict hierarchies.

Calling a Professional

Sometimes it is just better to call on a professional. This is particularly true if the pest problem is ongoing, if the infestation has become large, or if the products needed for control are only authorized for use by certified professionals.

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  1. "Winged Carpenter Ants." Michigan State University.

  2. Cranshaw, W. "Cluster Flies and Other 'Winter Flies.'" May 2018. Colorado State University.