Almost every time I go through the house to dust, I am amazed at the reoccurring corpses of flies on window sills. When I was younger, I assumed dead flies on window sill ledges meant they had died trying to get through the glass window. As it turns out, these nuisance pests are hardier than that, and bouncing against windows and window sills is not enough to contribute to the dead insects.
So if they don’t die there, what brings cluster fly corpses and other common types of flies to lie unmoving on the window sills? The good thing about it is that once you see the bodies, you can call a pest control service to stop a further fly infestation, whereas bug bodies in lights and on the floor are much easier to overlook while the problem grows. Read on to learn why flies die on window sills, what it means, and what to do about it.
Why are Dead Flies Always on Windowsills?
The main reason you will see flies and bugs near your windows is that insects are attracted to natural light. In most cases, flies that crawl into the house through window sills and window gaps and cracks will try to return back outside after exploring. The natural light coming through your ordinary window screens or window glass seems so close, but the barrier is real, and bugs and flies will die from exhaustion before finding their way back out.
Flies die everywhere, but they stay on window sills and are easier to find than ones that die in dark corners or on floors and carpets. When we repeatedly see multiple flies on our window sills, especially throughout the same day, it can be a sign of a fly infestation, the source of which you will need to find. Lights just inside or near windows, in general, will attract flies and other types of insects which may also expire on your window sills before morning.
How to Prevent Dead Bugs Dying on Sills?
Getting rid of any sources of infestation near your windows and in your home is the quickest way to prevent dead bugs from crowding your sills. If you see a few persistent bugs trying to get out, you can also open the window briefly to give them a better chance of out than through glass or mesh window screens. Make sure there are no signs of a fly infestation outside the window; however, more bugs may come in than go out.
When you clean the window sill regularly, there will be less dirt and grime to attract flies and pests. Cleaning the window tracks and screens can help you spot gaps and breach points that could lead to an infestation of flies. If your screens are constantly damaged, you can consider getting wire mesh windows that are more durable than some other types of screens.
If you have a current cluster of flies, then you should remove the bug infestations in the house to stop flies inside from dying trying to get out. Then you can prevent flies from coming inside and keep outside flies away from windows with sticky traps and natural repellents. When infestations subside, you can clean the window sills with a damp cloth to remove any food residue or dirt that may attract flies.
Signs of a Fly Infestation
Closing homes up for winter or bad weather should usually see the end of fly infestation but keep on the lookout because flies can appear on window sills any time of year. The more flies around the home more likely to have dead ones on the window frames, so keeping them out and staying on top of common sources of flies in the home can help.
Make sure to check in trash collection areas if you notice more flies on the window sill than usual, as flies lay eggs, and those eggs hatch quickly.
|Sign||What it Means||What to Do|
|Seeing Flies in the Home||Flies are able to get into your home or are breeding inside already||Find the entry point and seal it or destroy the breeding grounds|
|Maggots in Waste Bins||Flies have laid eggs and hatched maggots in your waste||Clean waste bins and use repellents/lids to restrict pest access|
|Excessive Fly Corpses on Sills and Lights||Flies can get inside your home but not escape||Check areas near where fly corpses are common for any obvious entry points and seal them|
What Do Flies Do on Windowsills?
There are many reasons flies will accumulate on window sills, with the main one always being the availability of food. They try to eat, escape, and mate but can’t make it outside even though it appears they can because screens or glass blocks them. Flies see light differently and may not notice the window glass between themselves and the path outside.
Flies will also try to warm up in the heat of sunlight when it is cold so they can fly and find food more actively. Flies become immobile when they get too cold, so the early light of the sun on window sills designed to catch winter light will keep flies alive and help them find food in cold conditions.
Continuously bumping into windows doesn’t harm the flies because they have a thick exoskeleton, but they will grow tired and need to take longer and longer breaks. Without an opening, flies will either find a new place in the home to hide or die on the window sills.