Why Birds Attack Windows and Mirrors鈥攁nd How You Can Stop Them

Have an aggressive bird obsessed with its own reflection? Protect it and your property with these simple tips.
A Northern Cardinal hovering in front of a window fighting its reflection.
Northern Cardinal. Photo: Cwhiteway/Shutterstock

It鈥檚 a pleasant spring morning, you鈥檙e lazing in bed, and then鈥clackety thunk-thunk clack!

A bird is thrashing away at your window and raising quite a racket. It鈥檚 annoying and it鈥檚 interrupting your sleep, but how about the bird? Is it sick? Frightened? What鈥檚 going on? 

Not to worry. This is a fairly common behavior during breeding season with a simple explanation: The bird sees its reflection in the window and is trying to drive away the potential rival. Northern Cardinals and American Robins are known for sparring with their own likenesses, but they鈥檙e not the only species to do so, and it鈥檚 common for both males and females. And the behavior isn鈥檛 limited to building windows鈥攂irds often attack vehicle windows and exterior mirrors, too. 

The bad news is that some individuals seemingly become obsessed with these phantom foes and might return to do battle day after day. 鈥淭hey have not adapted to the man-made invention of glass, so they see their reflection and they fight it,鈥 says Eli Haislip, manager at , a bird-feeding store in Nashville. 鈥淭hey鈥檙e not going to learn that it鈥檚 not real. It鈥檚 just going to become an ingrained behavior.鈥

To deter a bird from attacking its reflection, you鈥檒l need to get rid of the reflection.

The good news? This behavior typically isn鈥檛 harmful to the bird, and there are simple ways to stop it. (To be clear, this is not the same as a bird crashing into your window at speed, which is often fatal鈥here鈥檚 how to prevent that.

To deter a bird from attacking its reflection, you鈥檒l need to get rid of the reflection. The simplest way to do so is by placing something on the outside of the window鈥攊nside won鈥檛 cut it. Hanging a sheet, blanket, or piece of cardboard over the window will do the trick, Haislip says. (This might not be the most aesthetically pleasing solution, but it鈥檚 easy, and you should be able to take down the object after a few days.) 

Other experts recommend installing an exterior screen over the window, or marking up the glass with a bar of soap. Window decals designed to stop bird collisions can also prevent this behavior. 

If the window鈥檚 placement makes it difficult or unsafe to access, Haislip recommends anchoring Mylar balloons to a heavy object such that they鈥檒l float and flutter just outside the window. 

And if the bird is focused on a vehicle鈥檚 mirrors, the simplest fix may be to fold them in. Another quick and easy option is to cover them with paper bags when the car is parked. Opt for paper, Haislip says鈥攑lastic bags can mar your car鈥檚 clear coat. 

With these simple fixes, you can help a confused bird save its energy to overcome the real threats it faces. And you can get some well-deserved rest.