Cluster Flies - Why They Invade Homes and How to Keep Them Out for Good
There's nothing more annoying than hearing a constant buzzing sound near your windows in the spring or finding sluggish flies gathering around your attic or spare bedroom. If you've ever wondered where these sleepy, slow-moving insects come from, you're likely dealing with cluster flies—one of the most common but misunderstood pests in Southern Ontario homes.
They're not like houseflies and are not dirty in the same way, but they are persistent and can quickly overstay their welcome. Let's dive into what cluster flies are, why they choose your home, how you can keep them out, and how Barrier Pest Control helps families across Aurora, Newmarket, King City, Vaughan, Maple, Nobleton, Kleinburg, Schomberg, and Tottenham live cluster-fly-free.
What Are Cluster Flies?
Cluster flies (Pollenia rudis) are often mistaken for common houseflies, but they're a little larger, slower, and have a distinctive golden or brownish fuzz on their thorax. Unlike houseflies, which feed on garbage or waste, cluster flies don't pose the same health risks—but that doesn't make them any less frustrating.
Spring Cluster Flies awaken from hibernation, emerge from the cracks and crevices inside the home, and are attracted to the sunlight and warmth of the windows. They are trying to get outside towards areas to lay eggs in
Why Are Cluster Flies in My House?
Cluster flies are outdoor insects for most of the year. They lay eggs in the soil, and their larvae feed on earthworms—not garbage or decaying food like other flies.
They usually enter homes through:
- Cracks around windows and doors
- Gaps in siding or roofing
- Vents, soffits, and attic fans
- Openings around pipes or utility lines
Once inside, they find dark, secluded spots to settle in. You may not notice them until the first warm, sunny day of spring when they "wake up" and start flying around your home in a confused, sluggish state.
Are Cluster Flies Dangerous?
The good news is that cluster flies don't bite, sting, or spread disease. They're not attracted to food or waste and don't lay eggs inside your home. However, they can stain walls or curtains with droppings and leave an unpleasant odour when crushed.
Most of all, they're just plain irritating. Nobody wants to deal with swarms of flies every time the sun shines through a south-facing window.
How to Prevent a Cluster Fly Infestation
The key to managing cluster flies is to stop them before they get inside. Once they've settled into your attic or walls, they're tough to remove without professional help. Here are some steps you can take to reduce your chances of an infestation:
1. Seal Your Home Tight
Inspect your home's exterior in late summer or early spring. Use caulk to seal up cracks around windows, doors, siding, and eaves.
2. Repair Screens and Vents
Make sure window and door screens are in good condition and fit snugly.
3. Use Weatherstripping
Install or replace weatherstripping on doors and windows to prevent flies from sneaking in through tiny gaps.
How Barrier Pest Control Can Help
At Barrier Pest Control, we know cluster flies inside and out. We've helped hundreds of homeowners across Aurora, Newmarket, King City, Vaughan, Maple, Nobleton, Kleinburg, Schomberg, and Tottenham keep their homes free from these buzzing invaders.
We don't believe in quick sprays and empty promises. Our team takes the time to explain your options, tailor the treatment to your home's unique layout, and follow up to ensure lasting results.
Serving Your Local Community with Pride
We're proud to be a Canadian-owned and operated company and care about the families we serve. Whether you're in a cozy farmhouse in Schomberg, a newer build in Vaughan, or a heritage home in Aurora, we'll treat your home with the same care and attention we'd give our own. If you're tired of dealing with sluggish flies buzzing around every window the moment the sun comes out, don't wait until next season to take action.
📞 Call Barrier Pest Control today and ask about our seasonal treatments and home inspection services. Let's keep your space pest-free—naturally and professionally.