Bluebottle flies are the large, shiny flies that make the loud buzzing sound when they fly. They usually fly around windows and doors during the daytime. There are also green bottle flies, brass-colored bottle flies, and even black ones. Some people call them “blowflies”.
Bluebottle flies are scavengers. They deposit their eggs in decaying material. If they can find it, they prefer to use the carcass of a dead animal as the site where thy put their eggs. If that is not available, they often use garbage cans or animal droppings.
If homeowners find one or two bluebottle flies in the house, it is probably a sign of an outdoor infestation. It can mean that a door was left open or that a screen is torn.
If homeowners start to see a lot of bluebottle flies in the house, it may be a sign that something is wrong. Very often the flies are a sign of a dead mouse or bird in the attic.
The first, and most important thing to do is find the bluebottle fly breeding site. There will usually be a large number of flies buzzing around the site. If things are quiet, the buzzing sound may lead to the site.
If there is a dead mouse or bird, homeowners should not try to remove it barehanded. A trash bag can be placed over the carcass and used to grasp it. Invert the bag over the carcass so it ends up inside the bag. Place a second bag over the first.
After removing a carcass, it is sometimes necessary to apply an aerosol insecticide for fleas, bat bugs, beetles, or insect scavengers. Depending on the location, a dust insecticide may be easier to apply and be more effective than an aerosol.
Many homeowners who find bluebottle flies call a pest control professional. These people have the tools to make the inspection. They can also make any insecticide applications that might be necessary.