Why Do Bugs Die On Window Sills? (Important Facts)

Bugs commonly die on window sills because they are naturally attracted to light. They will fly toward any light source in an attempt to escape your house.

Oftentimes, the light source they go for is the sun that shines through your window. When the bug eventually dies, it will land on the window sill because it never stopped trying to get outside.

Bugs are very persistent when trying to get out of a house, and won’t register that the window has glass that is blocking them from getting through.

This is why they refuse to give up and will hit the glass over and over trying to escape. 

  • Bugs can die anywhere in your home, but window sills are the most common place
  • Bugs die for a variety of reasons including starvation, dehydration, and exhaustion
  • Bugs are attracted to light and can’t see when a window is in their way
  • Keeping bugs out of your home will stop them from dying on your window sills
  • Dead bugs will not harm you
  • You should clean dead bugs off your window sill to keep it clean

When bugs are dead on the window sill, what is the cause of death?

There is no definite way to find out the real reason that a bug in your house is dead, however, there are a few things that could explain it. One possibility is that the bug died from exhaustion.

Bugs will desperately try to get out through windows for hours at a time, and this will surely get tiring. They will eventually use up all of their body fat and die.

Another possible cause of death is hunger. Bugs that wander into your house won’t know where to find food, and looking for it can be a challenge.

Furthermore, if a bug is more focused on getting out of the house than finding food, they will be even more likely to die of hunger.

The last possibility is that the bug died from getting older and becoming too weak to get themselves food or water.

Bugs can die from old age but it’s very rare, and most often an insect will die because they lack the ability to find the nutrients they need to live off of.

This is similar to dying of old age because they are too weak to search, but in the end it really is just a lack of food and water.

Why don’t bugs realize that they can’t escape through windows?

Windows can disorient bugs because they are not used to being around glass and don’t understand what it is.

Windows block UVB light rays but let UVA light rays come inside, which may confuse the bugs because they can see light in a different way than humans.

The light may appear to look weird, which could throw them off and lead them to believe that the window isn’t there.

One good bug to use as an example is a fly. Flies have different eyes than humans, and because they have thousands of visual receptors they can see more things.

However, their vision is less focused because they don’t have pupils. This means that it is harder for them to register when there is glass in front of them, and all they are focused on is the fact that there is light.

If you are seeing a fly bump into a window repeatedly, it’s because the fly is confused and doesn’t realize that there is a sheet of glass in front of it.

You may wonder if the fly is getting hurt from bumping into the window and why it doesn’t notice the pain.

Flies actually have a tough yet flexible exoskeleton that protects them from getting hurt when they bump into a window, so all that it does is leave them a little disoriented.

Do bugs always die on window sills?

Bugs don’t always die on window sills, but they are by far the most common place to find dead bugs in your house. Bugs can also be found dead near other light sources such as doors and lamps.

Though finding a dead bug somewhere far away from a light source is rare, it isn’t out of the range of possibility.

Finding dead bugs near light makes sense because they are attracted to light and therefore want to be near it as much as possible.

Not only does light seem like a plausible way to escape the house, but it also makes insects feel safe from danger and predators. 

If you find a dead bug in a place where there isn’t a light source, it is most likely because they were looking for food and ended up dying in the process.

Most bugs don’t mean to end up in your house, and when they do it can be a struggle to find food to live off of.

How can you stop bugs from dying on your window sill?

There is no foolproof way to stop bugs from dying on your window sill. If they are in your house, the window sill will be the most common place to find them dead.

However, there are things you can do to keep them out of your house in the first place, as well as traps you can set if you don’t want to find them on your window sills.

If you want to keep bugs out of your house, you have to make sure it’s sealed up properly. Start looking for holes around baseboards and windows, and if you see any you can fix them with some caulking.

Also, make sure your window screens are staying up to date; patch any holes you may notice.

Avoid leaving doors or windows without screens open for long periods, especially at night when there is noticeable light coming from your house.

If you take precautions and bugs still end up in your home, there are ways you can catch them before they die on their own. For flies, you can use flypaper, which is a sticky trap that they will fly into and get stuck on.

You can buy flypaper at the store. You can also mix apple cider vinegar and dish soap to create a mix that will attract flies and gnats and trap them.

These methods are very effective when dealing with pests that have made their way indoors.

What should you do with dead bugs on your window sill?

If you happen to find any dead bugs on your window sill, you can get rid of them with a hand held vacuum or simply grab them with a paper towel and throw them in the garbage.

Some people may think that touching these dead bugs is dangerous, especially if they are flies, because flies are covered in bacteria.

However, unless you actually eat a fly, you are very unlikely to get any disease, and even then it is not a high risk.

If you are worried about it just use a towel and wash your hands afterward, and you will be completely fine.

What happens if you don’t remove a dead bug from your window sill?

If there are dead bugs on your window sill that you haven’t noticed or gotten around to cleaning up, chances are they will just stay there until you remove them.

Though if you have an animal such as a cat or dog who can reach the window sill, they may eat the dead bugs or move them around.

You may think that the bug will eventually decay if nothing else happens to it, but that is actually not likely. Bugs usually decay fairly quickly in the right conditions, such as in soil.

But bugs that die on your window sill, especially flies, will stay there for a very long time because they quickly dry out and it’s harder to decay that way.

So although a bug may decay on your window sill, it’s unknown just how long it would take and it’s more likely that you will clean up the bug before it decays.


The main reason bugs will die on your window sill is because they are attracted to the light and looking for a way out.

The window sill is the most common place to find dead bugs, however, they can be found anywhere in the home. They die for a multitude of reasons, but generally it is through hunger and exhaustion. 

If you want to keep dead bugs off of your window sill, your best bet is to use methods that will keep them out of the house.

If you end up finding dead bugs on your window sill, simply remove them and move on. 

Dead bugs are not the end of the world, though they can be annoying to constantly find in your home.

At least if you ever find a dead bug on your window sill again, after reading this article you won’t have to wonder why it’s there. 

Alright, that’s it for this article, here are a few hand-selected articles that you might also find interesting reads:

Why Do Dead Flies Attract More Flies?

30 Facts about House Flies you wont Believe!

Why Do Flies and Other Insects Hit Windows – ANSWERED!

Steve Foster

Mad about bugs and wanting to publish as many articles as I can to help educate people about these amazing beautiful creatures! For more info check out my about page https://schoolofbugs.com/about-steve-foster/

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