While cluster flies may look similar to regular house flies, they are usually found in greater numbers around windows and are very slow moving. They don’t transmit disease, since they normally live outdoors laying their eggs in earthworms not on food sources. They become a nuisance pest when the adult flies emerge in late summer early fall and enter homes to hibernate. Cluster flies prefer attics and wall voids and are sometimes called attic flies. They are sometimes tricked into thinking spring has arrived early by your home heating system. It is not unusual for 20-30 to be seen mostly on the top floor near light sources with smaller amounts as you get to ground level. This may occur anywhere from September to May. If you think you have a Cluster fly problem please give us a call or fill out the form to the right and we will get right back to you.