10/04/2026
When we first encountered cluster flies, it was the fall after we built the cabin. We assumed they were simply some flies that had found their way inside through the openings, since the cabin wasn’t fully sealed yet.
We thought a few sticky traps would solve the problem.
😂😂😂
They did not.
Our neighbours eventually enlightened us: cluster flies are just a common part of life up North.
Despite our best efforts, the flies stayed with us for almost the entire winter and then came back the following fall. And the fall after that. And the fall after that…
So at some point, we stopped fighting them and accepted them as part of the cabin experience.
We even started calling them “cuddly flies” because they have a habit of staying very close together, often clustering by the dozens (or hundreds) in the same sunny spot.
Here are a few fun facts about them:
🪰 They don’t bite. Unlike mosquitoes and blackflies, cluster flies aren’t interested in your blood. They’re generally harmless to people.
🪰 They don’t actually want your food. They’re not attracted to garbage or your dinner. Adult cluster flies feed mainly on plant material, nectar and other liquids.
🪰 Their larvae have a rather unusual life. They develop underground and parasitize earthworms before eventually emerging as adult flies. Scientists believe some North American cluster flies may have followed the introduction of European earthworms, which provided them with a suitable host.
🪰 They spend winter in buildings. In late summer and fall, adult flies look for sheltered places to spend the winter, cracks in walls, attics, around windows, under siding and, apparently, our cabin.
🪰 They can disappear… and then suddenly reappear. They may remain hidden inside walls for months and become active again whenever the building warms up on a sunny winter day.
Which explains why you can think you’ve won the battle in November, only to find a bunch of them sunbathing on your windows in January.
🪰 They’re found across much of Canada. They’ve been recorded in numerous provinces and are particularly common in rural areas.
So: seal the cracks. Repair screens. Caulk around windows and doors. Screen vents. Vacuum them up. And try to prevent them from getting inside in the first place.
As for us?
After several years of sharing our cabin with them, we’ve apparently moved beyond pest control and into coexistence.
Every fall, when the cuddly flies return, we just say:
“Oh, you guys again.” 🙄
