Cluster flies, also known as attic flies or autumn flies, are a common pest species in the United Kingdom. They are named for their habit of clustering together in large groups during the cooler months, often seeking shelter in buildings and homes.
Cluster flies are not harmful to humans, but their presence can be a nuisance. They are attracted to warmth and light, which is why they often congregate near windows or light fixtures. They can also leave a noticeable odour and stains on walls and furniture. One of the biggest challenges in controlling cluster fly populations is their ability to hibernate and survive through the winter.
When temperatures begin to drop, cluster flies seek out sheltered areas to hibernate, often in attics, wall voids, and other hard-to-reach areas of buildings. Once inside, they can be difficult to remove.
Preventing cluster fly infestations requires careful attention to sealing up cracks and gaps in a building's walls and foundation, as well as proper ventilation to reduce humidity and condensation. Pest control professionals may also recommend the use of insecticides or other chemical treatments to rid buildings of existing infestations.
While cluster flies may be an annoyance to homeowners, they are a relatively minor pest species when compared to other more harmful insects and rodents. Nonetheless, it is important to take measures to prevent and control cluster fly infestations to maintain a clean and healthy living environment.