Science Questions

Why do birds fly into windows?

Sat, 8th May 2010

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Treece Kampmeyer asked:

I have had a bird sitting on my deck ledge and he keeps flying off the ledge and right into my kitchen window over and over and over again. †He has been doing this non-stop for 2 days now. †What is wrong with this bird?


Kat - I think heís little bird brained!  Now, birds do fly into windows.  At home, my Mum has a lot of bird outlines stuck against the window to stop them flying into them. They fly into them for various reasons.  Firstly, itís clear glass - they might not see itís there.  They might think, ďOoh! That looks like a nice room, maybe a bit of floral wallpaper...Ē  Bang! Straight into the window.  So if you do have big patio doors, itís quite good to put stickers or something on them. 

The other thing is that the birds may be seeing their own reflection and, as it is the time of year when birds maybe get a little bit frisky, they start fighting with each other.  Maybe itís a male bird, and it will start fighting with male birds or trying to mate with lady birds.  So perhaps...

Chris -   Surely they should mate with feathered birds because lady birds are insects and are a bit small for a bird to mate with, arenít they?

Kat -   Female birds.  Thank you, Chris. 

So perhaps the bird is actually seeing its reflection in the glass and flying at it, trying to attack it and not realising that itís not another bird, itís its own reflection.  Especially with houses normally if the room behind it is quite dark, that makes the window look even more reflective and then act more like a mirror.  So I suspect that your bird is fighting some imaginary turf war with itself and thatís why it keeps flying into your window.  Try keeping the lights on in the room so that the roomís not so dark or try getting a cat or putting something like stickers or something on the window might help.

Chris -   Or a shotgun of course.

Kat -   Or a shotgun.  No!  That would be nasty.


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Treece asked the Naked Scientists:

Hello naked scientist:  

My question is that I have had a bird sitting on my deck ledge and he keeps flying off the ledge and right into my kitchen window over and over and over again.  

He has been doing this non-stop for 2 days now.  What is wrong with this bird?  

Is he crazy because he is driving me a little crazy.  I am a person that animals seem drawn to but this is ridiculous.

Please help,

Treece, Eagan Minnesota

What do you think? Treece, Thu, 6th May 2010

I recall there being a number of reasons why this might happen and it seems to depend on species to an extent.

It's possible that the bird is seeing it's own reflection, perceiving it as a threat to it's territory, and attacking it.  It may be worth putting some kind of gauze in front of the window to break up the reflection, and seeing if that helps.

Anyone else got any ideas? BRValsler, Thu, 6th May 2010

If the bird is one of the territorial species then I suspect that BenV is correct: that would seem to be the best explanation for the repeated 'attacks'. LeeE, Thu, 6th May 2010

I also think BenV is probably correct.  The house I grew up in has 9 6'x6' windows in the front, with 9 3'x6' windows above them.  Needless to say, birds flying into them was a significant issue, but most seemed to only do it once, as if they simply thought there was no glass then learned different.  This case would seem to probably be the reflection though, due to the repeated "attacks".  We hung outdoor drapes on the windows and my mom no longer has an issue with birds flying into them. norcalclimber, Thu, 6th May 2010

I have a similar problem at the moment with a bird continually battering itself against a window.

Pretty sure it can see its reflection and thinks it's a competitor. I have solved the problem for now by hanging a sheet over the particular window.

I've also had problems with birds attacking the mirrors and chrome on my truck! Geezer, Thu, 6th May 2010

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