Spring Cluster Flies

We have all had to swat away an occasional fly, especially outside during the summer. But what about when the flies seem to emerge in your home in large groups? That's when you know you may have a cluster fly problem. Read on to find out more about these nuisance pests.

What is a Cluster Fly?

Cluster flies are slightly larger than the common house fly and are often seen by homeowners in the fall and then again in the spring. Their coloring is greyish with black patterns and golden hairs. Cluster flies can be found throughout the United States, except in the states bordering the Gulf of Mexico, as well as in Canada and Europe.

What are the Behaviors of Cluster Flies?

In the autumn, cluster flies make their way to the sunny sides of homes in search of protected over-wintering sites. They do this in groups sometimes as few as a dozen or in groups as large as hundreds! Homeowners may notice large groups or clusters that have attached themselves to the side of a sunny building or window. As they make their way in through the cracks and openings of a home, they begin to hunker down for the winter. Many homeowners report seeing flies in their crawl spaces and attics during the fall months. On occasion, the flies reemerge inside homes when the weather warms only to go back into hiding when the temps dip again. In the spring, especially on warm days, cluster flies begin to come out of hiding spaces in walls and soffits and begin to work their way back to the outdoors. They do get confused and head toward light if they can not find a way outside. This is why many homeowners find cluster flies in large number by windows and doors.

What Should Homeowners Worry About?

Cluster flies do not bite humans or animals. They also aren't attracted to garbage. Their mouthparts, like many fly species, are like a trunk and used for sucking. They do not generally leave any damage to a home, unlike other pests, but they have been knowing to leave small dark-colored spots of excrement on windows and walls. Most homeowners should worry about the nuisance factor that comes with swatting at these flies in the fall, and then again in the spring. No one wants to be cleaning up fly carcasses around their windows and doors or explaining to guests why there are so many flies. Managing flies should be a part of an overall pest control solution. Be sure that your windows and doors are properly sealed and caulked throughout the home. Look for openings around utility pipes and dryer vents that could be allowing entry for all sorts of pests. If you find that you have a cluster of flies and need help controlling the issue, call Pest-End Exterminators now at 1-800-287-4321, 603-382-9644, or 978-794-4321.