Quick Answer
Cardinals tend to bang on windows because they see their reflection in the glass and think it is another bird intruding on their territory. The most effective ways to stop cardinals from banging on windows are:
- Install exterior screens on the windows to break up the reflection.
- Apply decals or hang strings and beads on the outside of the window to deter the bird.
- Use bird deterrent tape or spray made specifically for stopping window strikes.
- Place fake predator decoys like owls or hawks near the window.
- Trim back bushes and feeders near the window so the cardinal has an escape route.
Changing the window reflection, scaring the bird away, and removing things that attract the cardinal to that area are the best overall strategies. It may take some experimenting to find what works best for your specific situation. Persistence is key as it can take cardinals time to learn that the reflection is not a rival bird.
What Causes Cardinals to Bang on Windows?
Cardinals are very territorial songbirds that aggressively defend their perceived territories, especially during breeding season. When a male cardinal sees its reflection in a window, it often perceives this to be an intruding rival male cardinal infringing on its territory.
The cardinal will peck and bang its beak on the window repeatedly as a warning to make the other “bird” (its own reflection) go away. It may also chase its reflection and intimidate it by showing aggressive body posturing.
This is an instinctual behavior triggered by the cardinal seeing a simulated rival in its reflection. The cardinal does not realize the reflection is its own and that the window is not an actual threat. This leads to repeated window banging as it tries in vain to drive away what it sees as an intruder.
Some additional reasons cardinals bang on windows:
- Defending food sources – A cardinal may peck at windows near bird feeders as it tries to protect its food source from other birds.
- Attracted to reflection – The bright red color of a male cardinal can attract it to the mirrored reflection, thinking it is another bird.
- Abundant nearby – More cardinals in the area leads to increased territorial behavior and window strikes.
- Nesting instinct – Males may attack windows more frequently during nesting season as they are extra defensive of their mate and territory.
The territorial nature of cardinals combined with the reflection of glass windows is the core reason behind cardinal window banging. This explains why it tends to happen more frequently in springtime as birds become extra territorial during breeding season.
How to Stop Cardinals from Pecking Windows
Here are the top methods to stop cardinals from attacking and pecking your windows:
Add Exterior Window Screens
Installing window screens on the outside of the glass will help deter cardinals in two ways:
- The screen visually breaks up the reflection that the bird sees. This disguises the reflective surface and makes the window less mirror-like.
- The screen provides a physical barrier between the bird and glass so if it does peck, it hits the screen instead of directly banging the window.
Mesh screens work best as they obstruct the reflection while still letting natural light through. Make sure to securely attach the screens to withstand repeated bird strikes. Screens on frequently problematic windows can train cardinals to avoid that area over time.
Apply Window Decals and Dangling Deterrents
Adding patterned decals, tape, strings, or beads to the exterior glass can scare and distract cardinals from attacking. Try these deterrents:
- Window decals – Apply decal strips, spiderweb designs, or one-way transparent window film to windows.
- Bird deterrent tape – Specialized tapes exist with reflective surfaces or UV colors visible to birds but not humans.
- Wind chimes – Hang windchimes or vertical strings that move in the breeze.
- Shiny objects – Affix metallic streamers, aluminum foil strips, CD disks or metallic beads.
The moving and flashing nature of these items frighten birds. Placing them no more than 4 inches apart across the window disrupts reflections. Apply to the outside since markings inside will still reflect through the glass.
Use Bird Repellent Spray
Special bird repellent spray products are available that create a mildly irritating coating on windows. Some contain methyl anthranilate, a grape extract that temporarily irritates birds’ senses so they avoid the area. Reapply these sprays every few weeks according to product instructions.
Install Fake Predator Decoys
Setting up decoy owls, hawks or snakes in sight of the problem window can scare cardinals away. Lifelike predator replicas will trigger a cardinal’s natural wariness. Place varying types of decoys inside the window, on the windowsill or a nearby tree branch overlooking the window. Move decoys occasionally so they appear animated and authentic.
Trim Nearby Vegetation
Prune back trees, bushes and bird feeders within 3 feet of frequently struck windows. This eliminates protective hiding spots, so that a startled cardinal can easily fly away. Without cover, the cardinal is more vulnerable and less likely to attack the window.
Keeping the area immediately around the window clear means the cardinal has an escape route if the window deters it. Cardinals feel more confident attacking when they have good cover nearby.
Use Ultraviolet Liquid Bird Repellents
UV liquid repellents for windows contain an invisible dye that reflects ultraviolet light. This UV spectrum is visible to birds but not humans. When applied to windows, it acts like a warning signal that triggers an avoidance response in cardinals. Reapply monthly for continuous effectiveness.
Apply Temporary Window Paint or Soap
For quick relief during severe window attacks, apply temporary markings with soap, bird-safe paint or washable window markers. Create dots, stripes and geometric shapes spaced no more than 2 inches apart across the glass. Once the cardinal stops its attacks, you can remove these temporary markings.
Tips to Deter Cardinals from Windows
Follow these handy tips in conjunction with visual, physical and sensory deterrents for the most effective cardinal window damage prevention:
- Focus efforts on male cardinals – Males do most of the territorial window pecking, especially in spring. Deterring males curbs the majority of attacks.
- Block problematic windows – Close curtains/blinds in severely attacked rooms to block the reflection.
- Eliminate food/water sources – Remove bird feeders and water dishes near troubled windows.
- Make windows less reflective – Position sheer curtains to make the glass less mirror-like.
- Scare with sounds – Tap on the window or use predator bird calls to startle cardinals.
- Don’t tap back! – Never tap the inside of the window as doing so reinforces the behavior.
Keeping the above deterrent tips in mind improves your chances of successfully conditioning cardinals to avoid window reflections. Don’t give up if it takes days or weeks for cardinals to learn – persistence is key in outsmarting these territorial birds.
Preventing Cardinal Window Strikes
In addition to deterrent techniques, consider these preventative measures to stop cardinals banging on windows altogether:
Identify Problematic Windows
Closely observe which windows cardinals target and when attacks most frequently occur. This pinpoints prime locations to focus prevention methods. Track patterns over weeks or months for the best insights.
Apply Window Films
Install permanent window films that reflect ultraviolet light visible to birds. These films allow people to see out while creating a filtered appearance to deter birds. Films can be clear or tinted dark colors.
Use Special UV Glass
Replace problem windows with UV-A filtered glass that contains a special inner film blocking most ultraviolet rays. This specially formulated glass reduces reflections and prevents collisions. Though pricier, it provides a long-term passive solution.
Angle Exterior Screens
Angling exterior reflective window screens outward 15-20 degrees can divert reflections downwards away from a cardinal’s line of sight. This minimizes the mirrored impression that triggers attacks.
Place Glass Ornaments in Trees
Hang glass balls, aluminum pie plates or CD discs near trees adjacent to at-risk windows. These items create flashing effects when sunlight hits them, frightening cardinals from approaching.
Apply Window Grid Film
Adhesive window films with grid patterns divide reflections into smaller segments so birds see a fractured image instead of a threatening singular reflection. Grid sizes of 5cm x 10cm or smaller work best to discourage strikes.
Install Awnings and Sunshades
Using exterior fixed window awnings, shutters, sunshades or roof overhangs minimizes reflections off of windows. This eliminates the mirrored visual trigger for territorial cardinals.
When to Call a Professional
In severe cases of repeated cardinal window strikes, it may require professional assistance to completely resolve the problem. Seek professional help if:
- No DIY remedies deter the bird after several weeks of diligent effort.
- The same cardinal repeatedly returns despite employing multiple deterrents.
- The cardinal appears injured or is leaving bloody marks from collisions.
- Window attacks increase in frequency or intensity over time.
- You need window repairs from damage sustained by repeated striking.
Professionals can perform intensive deterrent techniques beyond standard DIY options that stand a better chance of retraining stubborn cardinals. They also have access to specialized bird control products. In extreme cases, removing problematic cardinals humanely may be required.
Getting professional help provides the best chance of stopping severe window banging issues. Be sure to hire only certified wildlife control experts for humane and legal bird removal practices.
Take Steps to Prevent Injury
Though cardinal beaks may seem small, repeated blows against glass can harm or even kill birds. Here are some steps you can take to avoid injuring cardinals that strike windows:
- Apply deterrents quickly at the first signs of attacks to limit collisions.
- Look for stunned or injured birds beneath windows and gently move them to safety.
- Dim lights at night to reduce reflections that can disorient night-flying birds.
- Follow all laws related to cardinal harassment and removal – only pursue humane options.
- Alert local wildlife groups about fatal strikes so they can monitor trouble areas.
With responsible deterrent measures, cardinal attacks can be significantly reduced to create a safe environment for both birds and windows. Persistence is vital, so implement a variety of different deterrents until you find the specific solutions that work for your situation. The beautiful songs and sightings of cardinals will provide ample reward for your diligent efforts to dissuade them humanely.
Deterrent Method | Pros | Cons |
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Exterior Window Screens |
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Decals and Danglers |
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Bird Repellent Sprays |
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Predator Decoys |
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Prune Nearby Vegetation |
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The Bottom Line
Cardinals attacking windows can be both a nuisance and a real danger to the birds. Using intelligent deterrent techniques tailored to your specific situation provides the best results for redirecting cardinal behavior humanely. Patience and persistence are vital, as cardinals will likely require consistency before learning to avoid the perceived rival in their reflection. With commitment to bird-safe practices, you can solve window collisions for good and enjoy these beloved songbirds visiting your yard.
Key Takeaways
- Cardinals attack windows due to seeing their reflection and perceiving a rival bird.
- Add screens, decals/danglers, repellents or predator decoys to discourage window banging.
- Trim vegetation by windows and use scaring tactics to make cardinals feel more vulnerable.
- Identify worst windows and apply deterrents quickly at first signs of attacks.
- Consider professional help for severe recurring cardinal window strikes.