They enter attics, dormers, and the highest rooms of homes during the autumn months by forcing themselves through various small cracks and openings. In Kansas, the most common attic fly is the face fly. The face fly is similar in appearance to the house fly, but is darker in color and often slightly larger. The markings between and beneath the eyes are silvery on face flies and golden on house flies. The cluster fly, a larger species with similar overwintering habits, may also occur in Kansas homes.
Cluster flies are usually more of a problem in Northern and Eastern states.
Just as the flies are a nuisance in the fall, while seeking hibernating quarters, they are again troublesome when they try to get outside. During winter warm spells and in the spring, many find their way from attics or wall voids into rooms, accumulating around the windows. In their semi-dormant state, the flies are sluggish and behave erratically. They may land on a person's face and return persistently after being brushed away. Contrary to popular impression, face flies do not breed and multiply in attics and homes, nor do they feed during the winter.