The common house fly can be recognized by the reddish eye color and the long stripes on the region behind the head. This fly is attracted to light and will fly to windows. Their numbers usually increase in late summer.
House flies often breed in garbage areas. The maggots can feed and complete development into adult flies within 10 days. The adult females may remain close to the original breeding site or fly miles to find new sites to lay eggs. Large numbers of house flies around the outside of a house or building, or inside, may indicate a nearby breeding site. It may be a dumpster or another concentration of garbage. House flies do not breed in dog feces.
House flies will intentionally enter houses and other buildings. Once indoors they are attracted to food odors and exposed food. They gather on windows in kitchens where food is available and the humidity is high. They are attracted to UV light that comes through windows.