While Calgary may be known for its Stampede and is still called Cow Town by some, it is much more a thriving metropolis than it is a ranch or a farm. In fact, Calgary is the third largest city in Canada. Yet even with its high rises, ring roads, and bustling activity, you can still find tranquil places throughout the city’s parks and river valleys. Unfortunately along with these beautiful green spaces and waterways come insects. Some, like pollinating bees and mosquito-eating dragonflies, can be a delight to see, while others can make us quiver. Among this group are cluster flies.
What Are Cluster Flies?
Cluster flies are larger than house flies and tend to swarm in groups. They are happy to live outside and particularly enjoy being in the sunshine. Cluster flies feed off flower nectar, not garbage or waste, and they do not breed in food or indoors, so having cluster flies is not a sign of unsanitary conditions. Nonetheless, it is annoying and can leave a bad impression on guests and customers.
Cluster flies are not dangerous to humans, but they can be parasites on earthworms. However, this is not harmful, not even for earthworms. Truly the most annoying thing about cluster flies is their tendency to invade our homes and businesses in large, buzzing swarms. This usually happens in the fall when outdoor temperatures cool down and cluster flies need a place to hibernate for the upcoming winter.
How to Prevent an Invasion of Cluster Flies
While they may take refuge inside for winter, cluster flies breed outdoors in fields and lawns. This is why, if you have a lot of grass or live next to a Calgary park or field with grass you will want to follow the following tips to limit the chance of an infestation of cluster flies in your home or business:
What to Do If Cluster Flies Invade Your Home or Business
There is little you can do once cluster flies enter your home or business. However, some property owners have limited success controlling their population through regularly vacuuming cluster flies and disposing of the vacuum cleaner bag and using natural repellents such as peppermint or lavender oil to deter them. However, the most effective solution is to call a professional cluster fly removal service in your area.
In Calgary, and elsewhere throughout the prairie provinces, that’s Poulin’s Pest Control. We have the expertise and experience to identify entry points, locate cluster fly harborage areas, and implement the most effective treatment plan. This includes the use of targeted insecticides and other effective methods to eliminate cluster flies at their source for a long-term solution. Our pest professionals also recommend effective preventative measures to stop future cluster fly infestations.
Cluster Flies or House Flies?
In addition to being larger than house flies, cluster flies differ from these more commonly known pests in several other ways. Here is a chart to help you easily identify the flies around you.
| Characteristic | Cluster Flies | House Flies |
| Appearance | 7-10 mm Dark body with a distinctive silver checkered pattern and golden hairs on their thorax | 3-6 mm Generally grey with four dark stripes on their back and reddish eyes |
| Behaviour | Slow and sluggish movement Cluster in groups Hibernate inside for the winter whenever possible | Quick, erratic movement Often alone or in small groups Active throughout the year |
| Habitat | Outside, grass Inside earthworms as parasites Warm, secluded areas of your home (i.e. inside walls and attics) | Very adaptable and can make their home inside or out Fond of places with high human activity Like moist environments, garbage, feces, and decaying organic matter like compost piles |
| Food Source | Flower nectar Inside earthworms | Human or animal food, waste, and garbage |
| Reproduction | Lay eggs outside near earthworm burrows | Lay eggs on decaying organic matter |
If you find your Calgary property invaded by either of these types of flies or other insects, pests, or rodents, call Poulin’ Pest Control. We’re happy to take control of the problem for you.
Take Back Your Property
Don’t let cluster flies scare your guests or customers.