Why Cardinals Peck at & Attack Your Window (6 easy Ways to Stop It)

Why is that cardinal pecking at, attacking, or flying into your window? There are a few reasons for this bazaar behavior and while they’re normal – we need to take steps to avoid these window strikes! In this article, I share the reasons why northern cardinals attack windows and how to stop them easily and safely.

I’ve been in your shoes before. With over 25 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 but some methods were impractical or ridiculous.

So, I took my experience, combined it with advice from avian professionals, and voila! My list of 6 easy ways to stop them was born.

6 Easy Ways to Stop Cardinals from Attacking Your Window

1. Move bird feeders
2. Adhere window film to the window (decals)
3. Draw invisible lines on the window
4. Hang reflective scare tape outside the window
5. Close blinds or drapes
6. Move outdoor/indoor plants toward the window

First, let’s understand why cardinals are bashing into your window to understand why my 5 tactics work.

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.

The same thing can happen with any reflective surface such as glass doors and mirrors.

Cardinals Perceive Their Reflection as a Rival Bird

Cardinals are not normally aggressive birds. However, things change during the breeding season. Starting in early spring and through summer they often exhibit aggressive behavior and fight hard against any rival bird that poses a threat to their reproductive efforts.

Cardinals are extremely territorial during nesting season. Both the male and female will aggressively defend their territory against rival 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 females.

When facing reflective surfaces, like a glass window, the birds can’t distinguish their own reflection from that of another cardinal. It’s instinctual.

The male cardinal sees his reflection in the glass window, considers it a threat (rival bird), and his territorial behavior kicks into high gear.

Why is a female cardinal hitting my window?

The female cardinal may hit your window when she sees her reflection in the glass. The appearance of another female cardinal kicks her into fight mode with a mission to eliminate the rival bird. She launches forward, hitting the window again and again. The impact can also sound like a bird pecking at the window.

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. The window is blocking their flight path!

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 easy and 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 recognizes it as a physical barrier and flies around it.

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. scrubbing soap on your windows makes them ugly).

Five Proven Ways to Stop Cardinals from Attacking Your Window

1. Move Your Bird Feeder

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.

Sound weird? I get that, I didn’t understand this guidance when I first heard of it either.

When a cardinal hits a window from less than 3′ away it won’t have had time to reach top speed, therefore, incurring little to no injury.

When the feeder is 30+ feet away they won’t be able to see a reflection.

2. Adhere Anti-Collision Window Film (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.

3. Draw Invisible Lines On the 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 a 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.

4. Hang Reflective Scare tape Outside the Window

Using strips of commercial reflective scare “tape” outside the window immediately breaks the reflection. These vertical stripes are usually about an inch wide and in varying lengths. Although it’s called strips of 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 tape in 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.

5. 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.

6. Move plants toward the window (Indoor plants & outdoor plants)

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.

Similarly, a large indoor plant can be moved closer to the window to break the mirror-like image.

Cardinals Also Attack Car Windows

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.

Strategies for Preventing & Reducing Injury from Window Strikes

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.

Avoid Dangerous Solutions to Stop Cardinal Window Strikes

• 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, and trees in your yard may pose a danger to 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? Birds can aggressively attack windows throughout the nesting 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.

Conclusion

Cardinals become aggressive birds during the breeding season and throughout the nesting season. When they catch a glimpse of themselves in a window, the reflection causes them to instinctually want to attack what they think is a rival bird.

Similarly, if they’re flying around your yard and turn toward a window they don’t realize it’s a physical barrier. Instead, they just see the world and keep flying.

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.