When Birds Collide

There was  a disturbing article about birds crashing into windows (or window strikes) in the Winter 2014 issue of Living Bird, the publication of the Cornell Lab of Ornithology.

Apparently the typical American home passively kills 1-3 birds per year through window strikes, likely more if there are bird feeders around. This may not sound like much, but it accounts for an estimated 44% of window strike deaths. (Estimates of bird deaths from window strikes range from 365 million to 1 billion in the US alone.) Almost all of the remainder come from low-rise buildings.

I would feel very sad if one of these rose breasted grosbeaks had a fatal window collision.
I would feel very sad if one of these rose breasted grosbeaks had a fatal window collision. This picture was taken last May.

While you would think that those tall glass skyscrapers would be a significant hazard for birds, in fact they account for only about 1% of deaths from window strikes.

Window strikes are an occasional problem with our back porch, the only part of our house with larger windows not subdivided into panes. In the ten years we have lived here, I have found two dead birds that seemed to have been victims of window strikes. However, it’s possible that there are more victims I never see.

Occasionally we hear a loud “thump!” while sitting on the porch, then realize that a bird had flown into the window. Generally they are stunned, but recover and fly away.

Recommended steps to reduce bird deaths from window strikes include:

  • Keep feeders within one foot of your windows. This prevents birds from building up speed before a crash. In our garden I don’t think this would be practical, as being close to the windows would convert bird feeders into squirrel feeders.
  • You can deck your windows with string, tape, decals or a special bird tape produced by the American Bird Conservancy.
  • Keep the window screens on or hang fine netting over your windows.
Male Baltimore Oriole
Same for this Baltimore oriole. Picture taken in our garden June, 2013.

The problem with the last two is that we like to take photographs of the birds from inside, so we’ll have to think about this. It is suggested that just putting up materials during the migration seasons could be helpful. Honestly, I’m not sure which if any of these steps we might take. When asked for comment, Judy stated plainly that she would not sacrifice her view of the garden in order to save a couple of birds. She’s very unsentimental, at least when it comes to birds.

Research is ongoing to develop window glass with patterns that can be seen by birds but not people. However, it does not appear that this is a technology that will be effective in the immediate future.

Are you concerned about birds flying into your windows?


60 Comments on “When Birds Collide”

  1. Very interesting! Yes! I find this very disturbing. As a kid there was one area of my parents home that always got hits and we actually rescued several injured birds and brought them to the bird sanctuary a town over from ours. I had no idea that the numbers were that high! That is mind blowing! I am happy to say that we have not had any that I have known about thus far. I do hope they invent something that will help the birds. Have a great week Jason…Nicole

  2. I had an ovenbird hit the window over my front door. It was such an odd place for him to be (never saw one before anywhere near my house), and certainly to have hit the window. Not near anything that would have attracted him or been in his way. He unfortunately didn’t make it. I wrote a piece on my blog about it last summer. It was sad.
    Occasionally I do have sparrows hit our larger family room windows, but they are usually just flitting in the bushes so it’s just a gentle bump.

  3. It happens occasionally, of course, but not too much. One time a little sparrow hit my upstairs bathroom window. Afterward, he landed on the 2nd story roof, right within view. He didn’t move for a bit, and then he looked stunned and just stayed in place for several minutes. I felt very bad and considered climbing on the roof to rescue him. But I didn’t. When I looked back out there about 30 minutes later, he was gone. So either he flew away or was food for bird of prey. Poor little guy.

  4. I’d read that the actual kill rate is much higher even than this as some birds are concussed and fly away only to succumb later to the effects of the concussion or to predation. I learned about a window film product called Collidescape and I’m thinking about using it on some of our windows–I want it for its anti-glare properties (we have a tree that is getting fried by window-glare), but increasing bird safety would be nice as well.

  5. Oh yes, last autumn was exceptionally bad – maybe something to do with the light. So we bought some transfers to stick on the inside of the windows (in the shape of snowflakes). The problem has definitely been reduced, athough a few still fly into our patio doors. The best solution so far has been on an outdoor partition where the birds often had accidents – I hung some shiny glass decorations that dangle and reflect light even when there’s hardly a breeze. The problem there is that they are noisy if it’s a bit breezy, but since it’s an outdoor area we don’t mind. I must try and do a post on this soon too Jason. Maybe someone has found the solution.

  6. Yes we occasionally have that problem, but I had no idea it was that common. We have large picture windows, stickers helped, we keep the blinds down on the upstairs rooms, creating a visual barrier, but thats not ideal downstairs. They do not seem to fly in to the glass when the windows need cleaning, but thats not ideal either. We also have starlings that nest in the eves, I wonder if they act as a deterrent.

  7. I’m with Judy and don’t want to sacrifice my view either. We sometimes have a problem, but I wonder what will happen when the conservatory is finished. In our last home we put stickers of birds of prey on the windows but the small birds soon got used to them.

  8. We have a lot of glass (whole facades of buildings), but we also have tall plants. I have only seen evidence of one window strike here in 14 years (a building which didn’t have planting around it at the time). I think the planting – climbers and small trees – may possibly be the reason we have so few. Our feeders are away from the house which probably helps. A very interesting post.

  9. The oriole and grosbeak are so colorful. I don’t think I’ve ever seen either in the wild before. I like the expression of the grosbeak. haha

    We have been pretty lucky and not had birds crashing into windows. I think that is as you say partly because of the placement of our feeder. It is -very- close to a window and I suppose the birds must slow down to land on it. We also don’t have a lot of open spaces so they probably can’t get up a lot of speed. They have to hop and pop down from branches.

    On the minus side that situation probably limits the birds we get to those who like thickly wooded areas — which might explain the lack of lovely birds like the oriole that visits you!

  10. This was a problem at my former home. It had more windows without screens and a large patio door that frequently caused them trouble. Haven’t noticed it here at all (12 years) even with two feeders. The oriole is so colorful–haven’t seen one in years.

  11. Thanks for posting this, Jason. Now you’ve made me feel a little bit better about my tiny yard (i.e. the feeders are close to the windows). But I never get Baltimore Orioles as far as I know. Shortly after I moved into my bungalow I had to replace the casement windows on the back porch and since it was impractical or too expensive to replace what was there, I opted for narrow double-hung windows to take up the same spaces as the casement windows. The contractor offered me a picture window for the same amount of money or maybe it was even less, but I knew it was bad news for birds. The screens regularly interfere with my ability to take pictures outside the back windows, but so be it. I think the biggest problem is that sometimes the outside birds see my inside birds and think they can fly in and join them. But this tends to be limited to House Sparrows and happens rarely. I thought someone was developing a window film but cannot find anything more current than this 2009 post on David Sibley’s blog: http://www.sibleyguides.com/2009/06/promising-new-window-film-may-prevent-bird-collisions/

  12. some good advice there Jason. We tend to have strikes on bonfire night, the fireworks terrify the birds and they fly into the glass, many have died that way. I often have birds fly into the house and occasionally have them fall down the chimney.xxx

  13. I work in a city of nearly 50,000, and walk by in one of the taller buildings (not tall by big city standards but still tall) every day – I have seen, from time to time, stunned birds on the sidewalk including one I believe may have been a fledgling peregrine falcon. (These falcons are known to roost on the roof of this building). The building in question is over 100 years old but the windows were replaced relatively recently. It would be wonderful if glass with patterns visible to birds but invisible to us could be developed.

  14. I get Living Bird here as well and the article on cats killing birds was really alarming earlier this year. Bird strikes at my home are not a problem in a house of 100 years. Also, it is not as much an issue with most residential homes. It is far more a problem in commercial buildings. The old glass of historic homes has many imperfections when originally created, so birds see it differently than new window glass. Also, mullions and muntins of older windows dissuade them too. Most commercial buildings would not necessarily have the closely spaces mullions and muntins either. New windows can be fitted or purchased with them for homes.

    • Cats are another issue I’m concerned about. I confess that our last cat was allowed to go outside and killed a number of birds over the years. If we get another cat we will keep it inside. And the millions of feral cats are also part of the problem.

  15. The birds that most often get killed hitting windows here are Northern Flickers. We also get some birds caught in the porch when the door is left open (mostly hummingbirds) but so far I have always been able to help them get out.

  16. You might request a sample of the clear CollidEscape. It’s supposed to be 100% effective for the birds–it does affect the view, though. I’m still trying to decide whether or not I will be able to tolerate the slight interruption of the view that it creates. Here in Seattle, we treasure every little bit of light and view we can get. And I’m not sure I’d want to use it on ALL my windows OR create a mismatched effect.

  17. In my previous house I put a large mirror on the wall to make the garden look bigger. It looked great but birds flew into it. In the spring a blackbird spent all day attacking his reflexion thinking it was a rival. I had to remove it because I was frightened he would injure himself. I have often seen mirrors in gardens and now I wonder how many birds get hurt or killed this way.

  18. Hello Jason. I was very interested to read this, it is an issue I’m concerned about. We’ve just built a barn here with large glass windows and the first thing I did was put up a couple of outline stickers of birds of prey to keep the garden birds away. The feeders are well away, too. I’m keen to make everything here as wildlife-friendly as possible.

  19. I was never concerned until we found one dead robin on the front porch as he had hit the front storm door. They nest in the trees off the porch. And one day I heard titmice fighting and one flew right into our french doors that have panes. He recovered but I wasn’t sure he would.

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