Why Don’t You See Dead Birds Lying Around?

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bird-374072_640As you walk around the city or countryside, you might occasionally spot a dead mouse, rat, or squirrel. Driving down the highway, you regularly see road-killed raccoons, opossums, or some other mammal. But how many dead birds have you seen? Maybe an occasional road kill, but that’s all. Why is that? Birds are light in weight, thin skinned, have little fat, are covered with feathers, and have some hollow bones, so they are less dense and weigh a lot less than comparable sized mammals. When a dead bird hits the ground, it is almost immediately invaded by small decomposers in the form of bacteria and insects. Vultures and coyotes might also take part in the feast, but the tiny organisms are usually the quickest and most efficient. Being thin and light, a small bird decomposes into an unrecognizable blob in about a day and will disappear in three. A larger bird will take a bit longer, but a small mammal, say a rat, might continue to exist in recognizable form for a week or more. A road-killed hawk or owl will be reduced to nothingness in a few days to a week while a fat, thick-skinned, heavy boned raccoon might lie as a blob on the shoulder of the road for two weeks or more.

Birds also float. If they land in a pond, puddle, or lake, they are exposed to the air and the scavengers and decomposers and rarely fossilize, compared to mammals that tend to sink and get covered by sediment. This explains why the fossil record of birds is so poor compared to other vertebrate groups.

There is a scientific paper published in 1903 by M. Cline. Now, this is before we knew much about flight, or even feathers. Ms. Cline stated, in all seriousness, that birds are able to fly because they take a deep breath of air, making themselves lighter than air (ok, already the argument loses credibility) and fly off. Her proof is that the piles of feathers you occasionally observe in the field or forest are the remnants of the birds that took too deep a breath and exploded! These feather piles are, of course, the aftermath of a poor bird meeting up with a predator. Raccoons, foxes, or opossums will consume the muscle, but leave the inedible parts – the bones and feathers. The bones are rapidly consumed by rodents who want the calcium and beetles ingest the feathers quickly as they are mostly protein.

The only time I have seen a number of dead birds is around bodies of water, after an epidemic of avian cholera hit the waterfowl populations. One of the weirdest things I ever experienced, though, is standing under a juniper tree talking to a colleague, discussing some subject of global importance, no doubt, when a swallow fell from the tree and landed in my outstretched hand, dead.

By the way, you can’t get West Nile Virus from handling a dead bird, but it’s still not a good idea to pick one up.


31 thoughts on “Why Don’t You See Dead Birds Lying Around?”

  1. Dr. Lederer,

    This is a question I have pondered and am so glad to have given Google a chance on this. I am an artist working mostly in clay (and some printmaking) and birding images are frequent in my work. I of course have had fanciful explanations always looking for metaphor in nature. Perhaps no less credible than Ms. Cline’s but certainly less violent. I was thinking about this recently because I saw a perfect circle of feathers but no body in one part of my garden as if a whirling dervish of a bird had spun off its feathers. It’s grey feathers looked like a mourning dove. The on the same day a tiny bird with yellow and grey feathers on my back steps. It sat there for days. Surprising because of the numbers of scavengers and predators that abound.

    In any case your explanation is as rich metaphorically as any. I thank you for your post. And if you have an idea as to why the little bird was still there – barely with any evidence of decomposition days later please speculate. It is February but we have had both 80 degrees one day and a low of 25 just a few nights later. For some reason many people think my last name is yours though it is an entire syllable shorter!

    1. Your description of circle of bird feathers reminded me of a fanciful theory I just saw presented as an answer to the question of where birds go to die on the website Quora. It took me a minute to understand answerer Mehul Soni’s verbose response, but basically this person was reporting someone else’s a theory that birds have an innate knowledge of when they will die (kind of like how they know when to fly south for winter), and that when it’s time for their life to come to an end, they simply fly up and up until the atmospheric conditions cause their bodies to naturally disintegrate. I think it’s probably more likely that old or diseased birds hide until they are eaten by predators or die and quickly decompose, but I prefer the flying up and up theory and will imagine it to be the true one from now on. 🙂

      Here’s where I read about that theory:

  2. Seanna O'Brien

    I find it staggering to pose a question I’ve been pondering ever since I saw a little dead Bunting 15 years ago, wondering why I had never seen a dead songbird before and having one who KNOWS respond to my query within days…THANK YOU!!!

  3. I recently brought a tropical plant I keep outside for the summer back into the house approximately 2 weeks ago when temperatures started to drop in the evening to around 0 degrees Celsius. This evening, I noticed that some of the leaves on one side of the plant were dying. I thought it was frost bite, so I cut off the dead leaves, finding it odd that it was only on one side of the plant, but perhaps it was on the most unprotected side. When I went to inspect closer, to my surprise, I found a dead bird at the base of the plant. My husband thought it was a warbler. He removed it (with gloves) and said it had already started to decompose. He mentioned that about one month ago there was a bird that was hanging out for days in our front porch. He noticed the bird flying off then returning over and over again. The bird seemed annoyed that my husband was there. He thinks the bird was likely sick, weak or tired, and decided to take refuge in our potted plant and eventually died there. Is this possible? Have you ever heard of this??

  4. Dr. Lederer,
    Thank you for your post! Would you mind sharing the M. Cline paper? A robin recently laid her eggs in a bush just outside one of our windows. As it’s right at the eye level of my two boys (8/6), they’ve become fascinated with birds. It would seem that she can’t see well enough through our screen/window to be frightened of us, and we’ve delighted in observing her. It will be amusing to share Cline’s misguided science and how they can use their own analysis to hypothesize. Many thanks for your informative writings!

  5. Barry N. Jared

    Hello Dr Lederer,

    My wife and I thoroughly enjoyed your post regarding the mystery of dead birds. As several others have requested, I wondered if you might share M. Cline’s “scientific” research paper. I have searched the internet and our local ( and very rural) library without success. Many thanks!

  6. I literally see dead birds everywhere, I’ve taken to the internet to find out why because it’s so annoying. At first it was fine but I keep seeing them, I’ve even watched a bird die in front of me for no external reason- it just fell over- i see a dead bird around once every two weeks

  7. Not convinced of any of this. I believe birds are so wise and precious, they are above our understanding

  8. I just found a dead bird on my backyard patio, a small pool of blood at its mouth (beak).
    I live in a small city in central NJ, so it’s a city bird. There are large trees around but about 30 yards (100 ft) away. No power lines either. I can count on one hand how many dead birds I’ve seen in my lifetime of 50+ years. I can’t help but wonder how and why.

  9. Stephen Fennell

    If the bird flew into a window (you said you found it on your patio), the impact could easily kill the bird and cause blood to appear around the beak. I hang things in the window now to give birds a chance of seeing there is something in the way.. They may see the reflection of the sky and think their way is clear, or, if the window is not bright from reflecting the sky but dark, they might be thinking they could take refuge in what might seem to them like a barn. Or they might be panicked by seeing a bird of prey somewhere, shoot off, and not have time to choose the best direction, and end up flying into the glass.

  10. Thank you for this. I was just wondering why it’s the case that we don’t see so many dead birds. I am glad I Googled it and came across your blog. If it’s possible, could you direct me to the Cline paper? Sounds quite incredible and I’m curious to see how they made their argument.

  11. Thank you for this clear answer to a question I have often pondered.
    I do like the fly to the sun theory.

    1. Jeffrey rader

      that’s exactly how i feel. There are probably over 100x as many birds as humans in Indiana (my own guess), and they are all living outside, in the open. There should be MANY signs of dead birds everywhere, every day. The doctor states that their bodies and bones decompose within a day or two… completely… with no trace.. ok..i don’t believe that, but let’s assume that’s true, because i can’t say definitely that it’s not… but feathers..i can say for a fact that when I’ve seen feathers that have been left behind after a cat has gotten one.. the feathers remain for several days or longer…. we should be seeing feathers everywhere…..

  12. I’m still not totally convinced. Okay they decompose quickly but think of the number of birds there are. Most don’t live many years. That means a huge number die each year. They may not last looking but we ought to see more remains around. But the truth is they are a very rare sight. I don’t have a better solution but I feel uncomfortable with this one. It’s easy to laugh at the ignorance of the past. One can only guess at the future’s judgement on us.

  13. We have a nest nearby the house . Birds swooping down, screaming. This afternoon a small bird dead on the sidewalk and the birds are still around watching and flying around us.

  14. I am still not satisfied… I am nature wanderer, I have never found a bird on ground which might have died few hours ago, or say 1 day.

  15. i have, on several occasions, thought about this. I once found a completely attached, but extremely clean pigeon skeleton in an abandoned house. However, that was the only one occasion when i saw bones of a bird.

    Do the bones decompose within such a short duration as well? I understand that they are hollow and light, it is still weird that you dont come across skulls, or fragments of bird bones ever….

  16. Hello! I’m a little late to the game here, but I just came across this page in doing research for a book I’m writing. This is all very interesting. Any chance I could get a copy of that M. Cline article? Thanks!

  17. I’m 71 years old and never remember seeing one dead bird I would say died of natural causes. Because there are so many birds I find the odds of never seeing just one bird as astronomical.

  18. Pingback: Where Do Birds Go to Die? Unraveling the Mystery of Avian Mortality - Birdograph

  19. Amanda Bennett

    Dr Lederer, thank you for your informative replies above. What an incredulous thing to have a swallow drop from a tree dead, into your hand! Perhaps a thank you for taking such an interest in birds!
    May I too have a copy of the article by M Cline. Thank you so much.
    Amanda Bennett

  20. I am perplexed that most are saying they don’t see many dead birds, I see them all the time, on a regular basis in fact.

    I found one on my balcony about a good month ago and decided to give her a little burial in a cooler full of soil – so as to hopefully send her little soul to heaven. I know it’s a her as I found a partial nest along the ledge when I was cleaning up after the incident.

    I had been keeping the bird due to “superstition” but have today decided to discard the cooler as my plants don’t seem to be doing well. I’m not sure if the dead bird has anything to do with the plants, but we have never had any issues before. As per this post the bird should have decayed in a few days, so not sure what to make of it all 🙁

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