He's telling that 'other' cardinal in the reflection to get the heck outta his territory. If he starts rushing it, and flying at it in a rage, you'll know for sure.

Meantime, you might get something to break up the reflection. . .and put it over the windows to keep the birds from doing that (as well as to keep them from flying into the window when they see the sky and trees reflected in it and try to fly to it).

OK. So I tried putting up things to break up the window. Even when I have a pillow over the area he usually looks into, he still flies at it. He has also found another window to peck at and fly into. I don't have curtains for these windows, but taping up scattered magazine pages has not helped-he goes around them. Aside from putting up curtains on the OUTSIDE of my windows, how do I get him to stop worrying? And me to stop being annoyed at the banging all day long.

I experienced this behavior on and off for several years at my last house. Big PITA. Not just the incessant banging, but the concurrent crap, as well. (Yes, the bird seemed to be evacuating it's insides as it hit the window or glass door...yuck.) There is little you can do besides covering the window with cardboard. We moved...though not because of the cardinal. :-)

Cardinals are notorious for this behavior. It's all about the territory thing for them. As the others have said, he doesn't realize the other bird is his reflection. We watched a cardinal to this to a parked mini van last weekend. It didn't take him long to find his relfection in the van's side mirrors.

I had a robin behaving this way a few weeks ago, made a mess out of my window. I was afraid it was going to hurt itself because I saw little bits of blood on the window from the severe pecking.

Like the others said, the only thing you can do is cover that window up best as you can.

Welcome to mating season, even though the skies the limit, they still seem to find one window to harass.

Things inside the window won't stop the reflection. Some one suggested covering the outside of the window with cardboard -- that will work. But if you want to be able to look out of the window, try cheesecloth or other white mesh material outside the window. From outside, the sunlight makes the white of the mesh brighter than the refection, so the reflection is not seen. But from the inside, you see the shadow side of the mesh, and the bright outdoor scenery is brighter and more visible. You may need to stretch the white mesh material over a frame to keep winds from blowing it aside. Or tape it to the frame of the window.

OK, so now it's almost December and my crazy cardinal has been pestering me everyday. I swear he now thinks we are cardinal, because he has flown into the window when I am in the computer room or laundry room .... when the sun is on the other side! It's kinda creepy. Yet, now, I think I'm going insane. I can;t realistically cover all of my large windows with cheesecloth. and if I did, for how long?

How long do cardinals live? Or stay in their territory? What if I get a fake cardinal or two ? I really can't move right now...

Put up some silver balloons so when he pecks it, it gives him a surprise?

I recall reading a book where a couple coated the window with vasaline and then cover it with toilet paper. I suppose one of the those christmas snow spray would work, too and is better looking.

Can you add a layer of fiberglass screen between the window and the cardinal. At least, it will deaden the sound?

Paul

I'm not hopeful. We've had a cardinal at our one window for two seasons now. In December I got desparate and tried to make a trap out of duct tape so when he came to the window the little guy would either not see his reflection, get scared away, or get stuck to the tape. He just worked his way into the little spaces between my tape. I'm trying to come to peace with the incessant tapping. That's not going so well.

We had birds flying into our windows. One woodpecker actually stood on the windsill and tapped on the window! Drove the poor dogs crazy! We went out and bought some UV reflective decals at the local bird food store. So far they seem to be working. I believe there were 4 clear maple leaf shped decals in the pkg. Maybe these would help in your situation? Just thought I'd mention it. Marg

Decals have worked for me to keep birds from flying into windows. I don't know if they would work to keep a bird protecting it's territory from attacking it's image or not. It might be worth a try. I bought mine at this link.

Cardinal has been visiting EVERY day for over 5 mos! He leaves for 15-30 min then comes back from sunrise to sunset.

Yeah, I have a female cardinal knocking at several windows spring, summer, fall for several years now. I've bought several fake owls and put them on poles in front of the windows. It works. (And it always scares me when I first open the drapes in the morning....hahaha)

I don't know if it's the same cardinal year after year, or if she taught her daughter to keep up the tradition.........but I wish she'd stop! She also is at our car side mirrors and poops all over the cars too. :(

Same thing is happening to us. The cardinal comes every 10 min or so and charges our window. He has now moved to our back patio and my car mirrors

I have a cardinal that has been at my basement windows for months. He has now added the front door and kitchen windows to his list. His mate is also with him sometimes. I have read that it is a departed loved one trying to let you know something...check into it. And by the way, they can live up to 15 years!

Do they ever tell you what it is the departed person wants to say?? ;)

Amazon has several varieties of the UV window decals, but visit windowalert.com first, as they have the complete line, also other cool related stuff, including a UV decal tester to see if yours need replacing. Note, they only last 6-9 months.

I have not tried this, so I don't know if it actually works. It claims to stop reflection attacking. http://windowalert.com/stop-bird-attack/ 
Quoting the website:

Some territorial birds vigorously defend their territory. These birds
perceive their own reflection in a window to be another bird competing
for their mate-and attack. Repeated attacks deplete a bird's energy,
putting its health and nesting brood at risk.

Stop Bird Attack eliminates the bird's window reflection, calms the
bird, and stops the attack. The product is a removable, white coating
that may be sprayed on any window under attack. Stop Bird Attack is
effective for Northern Cardinals, American Robins, California Towhees,
and other territorial birds.

For nearly two years now, I have a male redbird that constantly pecks at
my windowS, all year long. In using many ways to block any suspected
imagine, it doesn't matter, he will continue to peck. He was gone for a
week once and I actually worried about his demise, until now months
later, which he brought his girlfriend, and he always does in the
spring. To make it more concerning, if I leave the room, he actually
comes looking for me, even when I am upstairs, which is now creepy. I'm
just glad he sleeps at night because he is irritating to all in the house.

I have a male cardinal that pecks on my window only when I'm home alone !!! It's freaky

My stepdad died in November, ever since he past we've had a cardinal stop up at my moms window and the living room windows all the time and he won't leave. He comes bright and early in the morning and will visit in between both windows and start pecking at the window. We already tried covering them up but it's not working. What do i do?

This is not hopeful reading!! Just moved into a new home and Mrs. Cardinal has been non-stop all day, around one side of the house mostly. She is not deterred my my face popping up...gone for a couple minutes then back again, her husband waiting in the bushes behind. Some folks say to print large images of cats and stick them in the windows.. will try that.

Like I've said before, I've found that a fake owl propped up in front of their favorite windows helps. At one point I needed 3 owls at different windows. I got this pic before I bought the owl......... I think the mother cardinals teach their daughters to keep up the tradition. The "husbands" are always close by, and I'm sure they're saying "Now honey.........that's just your reflection........don't be silly." :)

I thought mine was also territorial. Male cardinal. Tap tap tap. We have three buildings. When I am in one he goes for those windows. I walk to the other building where I have my office. Bird follows me there and taps on those windows. Ditto the third building. Once I was sitting in my car with the door open and the cardinal flew in, brushed my face with his wing and taps on the inside of the door window! Can’t help thinking this is personal!

HU.........hahahaha Do you maybe have bright red hair? haha A long time ago I had my old pickup truck parked in the back yard. Every day, all day, the male cardinal would peck at that side mirror. When I finally got rid of the pickup truck, I sorta felt like I should put a post there with a mirror on it. haha Ever since though, it's always been the females pecking on all the windows......while a male is usually close by.

Just for the record, cardinals are not the only species. We are in the 4th week of a female bluebird constantly pecking at various windows and two years ago had a male towhee that had a thing for my car mirror for several weeks. Also have a catbird that follows me like a shadow when Im out working on the landscape. An aunt of mine many years ago told a story of a crow that would play practical jokes on her. She swore that it was her recently departed husband : )

Old Forester.......hahaha about the crow. :)

It started around the spring with an Oreo, then both Cardinals, then mostly the Male Cardinal. Now August is almost here, and it's mostly the Male Cardinal. After trying to scare them away with loud noises and lids to our pans, and a special noise making pest reducer, we put up an 8"x 10" picture of our cat and that seems to do it. Although we had to move our cars away from there and under our carport. They're still hanging around the house and trying other windows, but not as much.

We have a female cardinal now tapping at our window. She has been at it all day; when we covered one window, she went to another. I have ordered window decals from window alert to stop birds from running into our large windows. The decals do not seem to deter the cardinal. I will try as Chris G. suggest, and have ordered WindowAlert.com's "Stop Bird Attacks" window spray. That spraying this on a window eliminates the reflection and thereby stops the cardinals from window attacks. Testimonials at the product's site claim that it works, so we'll see. While waiting for the order to come, lol, I'll try the cat picture.

Wow, I've found the right place --- psycho bird victims unite! I've had male cardinal attacking my windows for 7 months now. I've tried covering windows, spraying windex(it was all I had) on outside of window, aluminum foil on outside of windows(I got creative for a while). If I cover one window he comes to another. He has now found my bedroom. This is from dawn to dusk and I'm not a fan of getting up at dusk! It's making me crazy, I'm smoking more, thinking of buying a gun(used to be a pacificist...) and losing friends! I've always been one to try to see a 'meaning' from the universe in odd moments but my love and peace tendencies are waning quickly. Please let me know if anything has worked ... I've got a lot of windows. Jeez, I just read they can live 15 years. I dont thidsfnk ihave thaat mch tiim lftt.