5 Proven Ways to Stop Cardinals From Attacking Your Window

A cardinal is attacking or flying into your window and you’re concerned for its safety – and it’s downright annoying! If you’ve spent more than 10 minutes researching how to stop cardinals from attacking your window, you’ve probably encountered a lot of really ridiculous solutions that either make your windows look ugly or are just too extreme to take action on. I feel your pain. Wouldn’t it be nice to have some practical solutions? Keep reading…

I’ve been in your shoes before. With over 20 years of experience in backyard birding, I’ve had my share of beak bonks on my windows. I’ve tried a variety of tactics to get them to stop and combined the results of those efforts with the feedback of my backyard birding colleagues and arrived at a list of 5 proven ways to stop cardinals (or any bird for that matter) from attacking your window. Even better, these tactics are practical and safe.

5 Proven Ways to Stop Cardinals from Attacking Your Window

  1. Draw invisible lines on the window.
  2. Hang reflective scare tape outside the window.
  3. Close blinds or drapes.
  4. Adhere anti-reflective anti-collision window decals.
  5. Move outdoor plants toward the window.

First, let’s understand why cardinals are bashing into your window to realize why my proven tactics work. If you’re in a hurry, skip ahead to the details of my 5 Proven Ways to Stop Cardinals from Attacking your Window.

Why Cardinals Attack Windows

When wild birds face your window, depending on the angle, they’ll see a reflection of themself or the sky/world around them. It’s like looking in a mirror.

YouTube video

Perceived Threats During Breeding Season

In the case of cardinals, and especially during the breeding season, they cannot distinguish their own reflection from that of another cardinal. It’s instinctual. Since reproduction is the primary goal of all wild birds, they will fight hard against anyone (bird) that poses a threat to that objective.

Cardinals are extremely territorial during mating season. Both the male and female will aggressively defend their territory against other cardinals as well as predators. While the red male cardinal typically defends the territory and his mate against other male cardinals, the female cardinal is highly protective of the nest and is primarily combative toward other female cardinals.

This is where the window comes in. The male cardinal sees his reflection in the window, considers it a threat, and violently attacks.

Similarly, the female cardinal sees her reflection in the glass, kicks into fight mode, and flies into the window again and again.

Cardinals Mistake the reflection for More Space to Fly

As mentioned earlier, the reflection the cardinal sees in the window can be mistaken for other elements behind them like the sky or just open space. As a result, they just keep flying like they normally would if it truly were open space.

How to Stop Cardinals From Attacking Your Window

There are a plethora of solutions flying around on the interweb – some effective & safe (e.g. my proven ways), some that are dangerous, and some downright ridiculous & unnecessarily extreme.

The ultimate goal is to break the reflection in the window so the cardinal doesn’t see anything but an object in from of him – like the house. The best solutions to breaking the reflection are safe for the cardinal, can be implemented quickly, have little to no cost, and are not invasive (e.g. won’t uglify the window or your home).

Five Proven Ways to Stop Cardinals from Attacking Your Window

1. Draw Invisible Lines On the Window

chartreuse lines drawn on window

Using a chartreuse highlighter marker draw horizontal lines about 2″ apart and vertical lines about 4″ apart (Perfection is not important). Birds can see the color but humans can’t. And, the marker can easily be cleaned off with window cleaner. Win-win! Alternatively, you can use a paint marker that can be scraped off.

The easiest way to implement this solution is to use a large level (tool) to draw straight lines and approximate the 2″ or 4″ intervals. Or, if straight lines aren’t your jam, try free-handing it.

2. Hang Reflective Scare tape Outside the Window

Window with reflective strips hanging

Using strips of commercial reflective scare “tape” outside the window immediately breaks the reflection. This product is usually about an inch wide and in varying lengths. Although it’s called “tape” it’s not sticky. This is a good thing because as they sway in the wind they won’t stick together. To implement, just cut strips of similar lengths and adhere one end to the top of the window while the remainder hangs. You can still see out your window with minimal interference.

3. Close blinds or drapes

You can close your blinds or drapes to get the behavior to stop immediately. If after opening them again the bird continues to attack the window, you may need to circle back to one of the other proven effective & safe methods.

4. Adhere Anti-reflective Anti-Collision Window Decal

Window with anticollision decals

There are many commercial products specifically designed to break up the expanse of the glass surface to eliminate reflection. Many are pretty cool looking – almost appearing like etched glass. You’ll have to experiment with how many you will need. In order to be effective, you may need several to fully break up the reflection – especially for very large windows.

Check out these highly-rated decals on Amazon.

Alternatively, check out your local craft store for cute children’s themed window decals. It won’t be as pretty, but still be effective.

5. Move outdoor plants toward the window

Many times the offending window is a patio door. With that, if you happen to have potted plants outside the patio door and the cardinal is attacking it, try moving the potted plant(s) closer to the window to break the reflection.

Cardinals Also Attack Car Windows

Female cardinal attacking a car window
Female cardinal sees her reflection in a car window and goes on the offensive. Photo by Bobby Glenn Lanier.

The solutions above are specific to windows in your home. Cardinals are also notorious for attacking car windows for the same reasons mentioned but the solution is much easier – move your car.

Mitigation Strategies

Prevention. Since cardinals are ground foragers you could set up an area on the ground for them which eliminates their reason for looking into the window in the first place. Put a very low tray feeder on the ground and/or scatter seeds around.

Reduced Injury. Since you don’t know when a cardinal will decide to start attacking one of your windows or which window will offend the bird, one mitigation strategy you can implement is to ensure your bird feeders are within 3′ from the window or more than 30” from it. In fact, this is a standard best practice whenever you are hosting birds in your yard. If a bird is at the feeder and taking off toward the window, it won’t have had enough time to smash into the window at top speed thus the damage.

Dangerous Solution to Stop Cardinals From Attacking Your Window

  • Hang Fishing Line Strips. A popular recommendation is to hang strips of fishing line outside the offending window. The idea is that the birds can see the fishing line, especially when the wind blows, but humans cannot. The danger is the fishing line is so thin and bendy the bird is at risk of getting tangled in it and getting injured or worse – killed.
  • Remove the perch. In addition to being impractical, removing shrubs, trees in your yard may pose a danger for the cardinal. Perching spots allow cardinals to scope the area for predators and in some cases, hide from said predators. This approach also gets the award for the most impractical solution (who wants to dig up bushes and trees?).
  • Bird Netting. Gardeners often use bird netting to keep birds away from their crops. This tactic doesn’t end well for a lot of birds. Similar to the fishing line approach above, the bird can get tangled in the netting and get injured and/or die waiting to be freed.

Ridiculous Solutions To Stop Cardinals From attacking Your Window

First, let me preface by saying in the unlikely event one of my proven strategies doesn’t work for you, one of these ridiculous or extreme solutions just might do the trick. Desperate times call for desperate measures, right?

Here we go – below are solutions others recommend that would not be my first choice in addressing the cardinal attacking my window problem.

  • Let the window go dirty. To be honest, I don’t even think this approach will work. Don’t ask me how I know 😉 For those of you who are diligent about cleaning windows, it’s unlikely you would want to let them go dirty – especially if another solution will work. Besides, if you have clean windows when the cardinal starts attacking it, the poor bird will suffer brain damage waiting for it to go dirty. You need a more immediate solution.
  • Soap windows. Similar to letting the windows go dirty, writing with soap on your windows strikes me as ridiculous. Who wants to look through a cloudy, marked-up window when there are easier ways? Breeding birds can aggressively attack windows throughout the season so your soapy windows could be there for some time. Eugh.
  • Install an awning. If you planned to buy and install an awning anyway, this tactic is cool so carry on. However, I doubt that’s the case. To install a contraption to the exterior of your home is what I consider extreme and costly. Some might even consider this approach an eyesore. This approach also has an issue with timing. Just how quickly can you get this awning purchased and installed?
  • Install blinds on the outside. Sure, this fix will work but the wind, rain, and snow will likely destroy the blinds or cause them to swing around and destroy your house! Similar to the awning solution, implement this solution if you already planned on it installing outside blinds. Otherwise, abandon it for an easier fix.
  • Cover the window with a tarp or painter’s drop cloth. If ever there was an ugly solution, this is it. Enough said.

There is no shortage of solutions and opinions on the best way to stop cardinals from attacking and flying into your window. Always avoid dangerous tactics! Implement the ridiculous and costly ones if you have the time and money. Or, do what the rest of us practical folks do, implement one of my proven ways to stop the cardinals from attacking your window. It leaves you with more time to enjoy the birds.

More than 25 years ago, Tammy put her first bird feeder outside her kitchen window. Since then she learned how to attract wild birds to her backyard. Studying the meaning & symbolism of wild birds is also a passion of hers. Read more about Tammy