Why do Bluebirds fly into windows?

Bluebirds are absolutely stunning and if you weren’t aware of their nesting behaviors, these little guys and gals prefer trees with knotholes but are absolutely in love with nesting boxes, too!

Due to this proclivity, many fans of these blue and orange beauties leave boxes out in their backyards in hopes of attracting these lovely birds. One question we get a lot is this one:

Why do Bluebirds fly into windows? The 3 primary reasons for this behavior include the reflective qualities of the glass, the bird’s territorial nature, and some have even suggested that this is ‘alerting behavior’ that you are seeing from these birds. 

Today we’ll expand a little of each of these suggestions so that you can have a better idea of what is likely happening and what you can do to help minimize or maybe even prevent this behavior. 

Reflective Glass and The Lighting Behind It

blue bird and windows

Window glass is shiny and as long as the light outside is brighter than the light inside, then your window will be highly reflective.

When a Bluebird sees the glass from a distance then they could just be seeing the reflection of what is near to the glass rather than the glass itself.

This is dangerous, of course, as the birds can seriously hurt themselves on the glass.

 Thankfully, there are a few things that may be done in a case like this:

  • Ultraviolet stickers may be placed on the windows. Bluebirds and other birds can see on the ultraviolet spectrum so stickers placed 2 -3 inches apart on the glass may prevent these birds from flying into the windows.
  • If the window doesn’t have an outer screen, sometimes simply installing a screen can fix the issue – though it might not be the reflected area that the bird is responding to (more on this shortly).
  • If you have a bird feeder near the window, simply moving it a little farther away may take care of the issue. 
  • You can even put an outdoor plant outside the window to reduce or minimize the light reflection.

Bluebirds Are Quite Territorial in The Spring

Another possibility as to why Bluebirds keep flying into the glass is that they may be seeing their reflections in the window.

Thinking that another bird is in their territory, your backyard Bluebird is responding by trying to drive that ‘other bird’ away.

This behavior is most often seen when these birds are protecting eggs or newly hatched chicks.

Sometimes they will ‘divebomb’ humans in the backyard as well and while this can certainly get your heart racing, it is very normal behavior for Bluebirds.

Northern Cardinals and American Robins are notorious for this as well but you do have a few things that you can try:

  • Make sure that your backyard nesting boxes are at least 100 feet from your house. While you’ll surely have to wait for next season, keeping the nesting boxes farther away can prevent this issue in the future. In the meantime, try the UV stickers to help minimize the strikes.
  •  If this is occurring with only one window and you notice that the Bluebird has a favorite perch nearby, relocate or remove that perch area if you can. This will help to keep them from watching that window and should minimize strikes.

The Popular Explanation of ‘Bluebirds Alerting Behavior’

If your backyard Bluebird is not flying at full speed but rather just lightly ‘thumping’ into the window then some birding enthusiasts have a 3rd suggestion.

We should note, that these are wild birds, so anthropomorphizing their behavior is a slippery slope.

That said, some birders claim that their Bluebirds have sometimes lightly thumped into windows to get their attention.

One story, for instance, is that an insistent Bluebird kept thumping lightly on each of the windows until someone went outside to check the nesting boxes.

After cleaning out twigs that Wrens had placed for their own nests inside, this birder reported that the ‘thumping’ behavior ceased. 

Bluebirds have also been said to ‘beg’ a little when the feeders are running short of mealworms, by landing on the screens outside a window with a small, but audible thump. So, do bluebirds eat dried mealworms?

Sometimes they even just perch on the screen and look into the windows as if they are looking at us.

Whether or not ‘alerting behavior’ is real is a subject up for grabs, but there are certainly videos out there that seem to suggest this.

Final Advice

Now that you know the primary reasons why Bluebirds fly into windows we just wanted to give a couple of last minute suggestions.

If you don’t have access to UV stickers, an ugly but effective solution is to simply stick some opaque pieces of tape spaced between 2 and 4 inches apart on the window.

Netting that is hung loosely over the glass is also reported to be highly effective.

While these last-minute tips are a bit unattractive, they can certainly buy you a little time while you implement a more permanent solution. Just be patient with the process.

Once you know if it’s the reflectivity, territoriality, or the Bluebird simply trying to tell you something then one of today’s tips should do the trick! 

Related Questions

Why is a bluebird trying to get in my window? Bluebirds see their own reflection in the glass and believe that as another bird trying to intrude on their territory.

What does it mean when a bluebird taps on your window? Bluebirds are stunning and when they tap on your window, it typically means that they saw their own reflection and believed it as another bird. But some people believe that when bluebirds tap on your window, it means you are going to get some joyful news.

How to stop birds pecking at windows? There is only one solution to stop birds from pecking at windows, i.e, cover the windows and get rid of the glass reflection.

Donald Bergeson

I have always been fascinated by the skill, strength, and beauty of birds.They help in maintaining a balance of ecological environment. At Best Bird Guide, I share all of my experiences and discoveries that I have got so far and inspire more devoted fans.

Recent Posts