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 Often known as 'attic flies'


At first glance, they may look like house flies, but they are larger, darker and slower-moving. There tends to be more of these flies in houses surrounded by large lawns or those backing onto open parks. The name "cluster fly" is used because of their habit of gathering in clusters after entering a house in the fall. They may give off a sickly, sweetish odour if disturbed.

Cluster flies hibernate in secluded areas of houses (like in wall voids, attics, closets, and empty rooms). They  can enter your home through the tiniest cracks around door and window frames, but also through any other small unsealed opening. They are a particular nuisance because they leave stains on walls and curtains. Also, if flies die in wall voids, they may attract larder beetles, which will feed on the dead flies and then migrate to other areas of the house.

Adult cluster flies start looking for winter shelter when the days shorten in late summer and early fall. They are often attracted to the warm south and west sides of buildings, particularly those located in open and exposed areas. After sunning themselves during the day, the flies will look for a warmer place as the sun goes down and will eventually crawl into any small opening they can find in the house siding or under eaves. They may then settle within the walls or attic to hibernate.


Choose to contact Heritage Pest Control to solve the problem.

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