# Why Do Pigeons Bob Their Heads? **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [December 5, 2008, 2:12pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847 "2008-12-05T14:12:21Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![James\_Randi](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@James\_Randi](https://boards.straightdope.com/u/James_Randi)\ **Post date:** [December 5, 2008, 2:12pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/1 "2008-12-05T14:12:21Z")
I had a older friend who had only one good eye. He would – automatically – “bob” his head before reaching out to contact something like a proffered hand, to “scan” for a 3-D location… And, he was unaware that he did this. When shown a video of the action, he was astonished! Perhaps pigeons also employ this method to locate, given their “side-mounted” eyes? And, one has to wonder, are they aware of this, or do they really care…? ---
**Author:** ![SeanArenas](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@SeanArenas](https://boards.straightdope.com/u/SeanArenas)\ **Post date:** [December 5, 2008, 2:32pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/2 "2008-12-05T14:32:51Z")
[Why do pigeons bob their heads?](http://www.straightdope.com/columns/read/17/why-do-pigeons-bob-their-heads) ---
**Author:** ![ivan\_astikov](https://avatars.discourse-cdn.com/v4/letter/i/58f4c7/32.png) [@ivan\_astikov](https://boards.straightdope.com/u/ivan_astikov)\ **Post date:** [December 5, 2008, 2:33pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/3 "2008-12-05T14:33:19Z")
I know you are going to get people coming in here with differing opinions, but the truth is, they like it. ---
**Author:** ![Irishman](https://avatars.discourse-cdn.com/v4/letter/i/b487fb/32.png) [@Irishman](https://boards.straightdope.com/u/Irishman)\ **Post date:** [December 5, 2008, 4:45pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/4 "2008-12-05T16:45:31Z")
From the column: > [@](#): > > For an animal with side-mounted eyes, forward movements result in parallax shifts (apparent motion of near objects relative to distant objects). Now, vertebrate eyes–and retinas–work much better with completely stationary images. So what happens is that the bird’s body walks on while the head is temporarily left behind to stabilize the image. The head is then jerked forward at the start of the next step. > > Owls and humans, by contrast, have front-facing eyes, and thus, no parallax problem while walking. Heavy-headed creatures with side-mounted eyes (pigs, cows), for which the avian solution is impractical, apparently were dumb to start with and have grown to enjoy parallax shifts. If the aforementioned blather continues, maybe you and your critic along with Pettingrill should consider having your eyes remounted to match your wits. --Martin S., Chicago This does not make sense. Pigeons are smarter than cows? How come cows and pigs can function with parallax shifts, but pigeons can’t? Unexplained. Furthermore, how do pigeons fly, if parallax shifts are so much trouble? Do they bob their heads when they fly? ---
**Author:** ![Gregor](https://avatars.discourse-cdn.com/v4/letter/g/6a8cbe/32.png) [@Gregor](https://boards.straightdope.com/u/Gregor)\ **Post date:** [December 6, 2008, 10:55am UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/5 "2008-12-06T10:55:35Z")
The forward motion of the pigeon provides a parallax shift… no need to bob in flight. The bobbing is also mating/challenging behavior perhaps? ---
**Author:** ![Nametag](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nametag/32/406_2.png) [@Nametag](https://boards.straightdope.com/u/Nametag)\ **Post date:** [December 7, 2008, 6:50pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/6 "2008-12-07T18:50:34Z")
Martin S’s screed being virtually unreadable, I refer the reader to this article (Warning: PDF): [Frost, B.J. The optokinetic basis of headbobbing in the pigeon. Journal of Experimental Biology, 1978, 74, 187-195.](http://jeb.biologists.org/cgi/reprintframed/74/1/187) Back in the late seventies, Barrie J. Frost, a visual neuroscientist at Queens University in Kingston, Ontario, put pigeons on a tiny treadmill. They walked, but they didn’t move relative to their environment-and they stopped bobbing. ---
**Author:** ![drewbert](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/drewbert/32/15890_2.png) [@drewbert](https://boards.straightdope.com/u/drewbert)\ **Post date:** [December 7, 2008, 7:18pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/7 "2008-12-07T19:18:00Z")
[Demonstration of Chicken Keeping Head Stable As Body Moves](http://laughingsquid.com/demonstration-of-chicken-keeping-head-stable-as-body-moves/) ---
**Author:** ![maggenpye](https://avatars.discourse-cdn.com/v4/letter/m/ecc23a/32.png) [@maggenpye](https://boards.straightdope.com/u/maggenpye)\ **Post date:** [December 7, 2008, 8:04pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/8 "2008-12-07T20:04:32Z")
[QUOTE=Nametag] Back in the late seventies, Barrie J. Frost, a visual neuroscientist at Queens University in Kingston, Ontario, put pigeons on a tiny treadmill. They walked, but they didn’t move relative to their environment-and they stopped bobbing. Reply With Quote [/QUOTE] \*Pigeons \*on a treadmill? This is some kind if sick doper in-joke, isn’t it? Or the latest from the Game Room, how many Cecil columns can be referenced in a single question. And, **Gregor** , if the parallax shift is provided with the forward momentum of flight, why is it an issue with the forward momentum of walking? ---
**Author:** ![aruvqan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aruvqan/32/2891_2.png) [@aruvqan](https://boards.straightdope.com/u/aruvqan)\ **Post date:** [December 7, 2008, 8:43pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/9 "2008-12-07T20:43:17Z")
> [@maggenpye](#): > > \*Pigeons \*on a treadmill? > This is some kind if sick doper in-joke, isn’t it? > Or the latest from the Game Room, how many Cecil columns can be referenced in a single question. > > And, **Gregor** , if the parallax shift is provided with the forward momentum of flight, why is it an issue with the forward momentum of walking? why not … there is a youtube of a shrimp on a treadmill=) ![](https://img.youtube.com/vi/cMO8Pyi3UpY/maxresdefault.jpg)https://www.youtube.com/embed/cMO8Pyi3UpY?feature=oembed&wmode=opaque ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [December 7, 2008, 9:41pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/10 "2008-12-07T21:41:52Z")
It’s really simple, there is a string that connects the pigeon’s head, and its legs. ---
**Author:** ![maggenpye](https://avatars.discourse-cdn.com/v4/letter/m/ecc23a/32.png) [@maggenpye](https://boards.straightdope.com/u/maggenpye)\ **Post date:** [December 7, 2008, 10:09pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/11 "2008-12-07T22:09:38Z")
> [@aruvqan](#): > > why not … there is a youtube of a shrimp on a treadmill=) > > [http://www.youtube.com/watch?v=cMO8Pyi3UpY](http://www.youtube.com/watch?v=cMO8Pyi3UpY) I’m not clicking that, it could be a [shrimp roll](http://sushiday.com/archives/2006/11/04/crunchy-shrimp-roll/) and I heard enough Rick Astley in the 80’s. Besides, youtube makes my PC go paralytic. … Maybe headbobbing would help. ---
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [December 8, 2008, 7:34pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/12 "2008-12-08T19:34:54Z")
> [@Nametag](#): > > Back in the late seventies, Barrie J. Frost, a visual neuroscientist at Queens University in Kingston, Ontario, put pigeons on a tiny treadmill. They walked, but they didn’t move relative to their environment-and they stopped bobbing. I actually came into this thread just to suggest putting pigeons on a treadmill, but apparently I was 30 years too late. ---
**Author:** ![PetroDude](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@PetroDude](https://boards.straightdope.com/u/PetroDude)\ **Post date:** [December 8, 2008, 10:21pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/13 "2008-12-08T22:21:08Z")
> [@James\_Randi](#): > > I had a older friend who had only one good eye. He would – automatically – “bob” his head before reaching out to contact something like a proffered hand, to “scan” for a 3-D location… And, he was unaware that he did this. When shown a video of the action, he was astonished! Perhaps pigeons also employ this method to locate, given their “side-mounted” eyes? And, one has to wonder, are they aware of this, or do they really care…? For another one-eyed data point, I’ve only had one good eye since birth. I do not ‘bob’ for location or for scanning. I have checked with Mrs. Petro and she agrees and has never seen me do this. I believe since my good eye is still forward facing, I compensate by other means. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [December 8, 2008, 10:24pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/14 "2008-12-08T22:24:02Z")
Since an old, old SD classic has been revived, I’m reviving my response: [Did Tyrannosaurus Rex bob his head when he walked?](http://boards.straightdope.com/sdmb/showthread.php?t=137237) ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [December 8, 2008, 10:40pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/15 "2008-12-08T22:40:36Z")
They’re F. Scott Fitzgerald fans and they don’t have any hair? ---
**Author:** ![Oukile](https://avatars.discourse-cdn.com/v4/letter/o/13edae/32.png) [@Oukile](https://boards.straightdope.com/u/Oukile)\ **Post date:** [December 9, 2008, 9:02am UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/16 "2008-12-09T09:02:55Z")
More than reducing motion parallax, the head-bobbing reflex of the pigeon will also reduce retinal slip. Retinal slip is the motion of the image of the world on the retina when the eyes move relative to the surrounding. A bad eye stabilization will mean a lot of retinal slip which does not only reduce visual acuity (which is, anyway, not really high in pigeons. However, try to shake a book in front of your eyes and to read it on the same time) but also decrease visual motion perception (which is quite usefull for detecting predators). In brief, it is much easier to detect something moving in the middle of a stable image than to analyse a moving image and look for something that moves differently. Notice that virtually all vertebrate species have an gaze stabilization system (the eye move to compensate head motion) known as vestibulo-ocular reflex. This reflex will work during head rotation (which doesn’t cause parallax), indicating that its primary purpose is to minimize retinal flow. ---
**Author:** ![SeanArenas](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@SeanArenas](https://boards.straightdope.com/u/SeanArenas)\ **Post date:** [December 9, 2008, 1:32pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/17 "2008-12-09T13:32:16Z")
Maybe the pigeons are bass players. ---
**Author:** ![Oukile](https://avatars.discourse-cdn.com/v4/letter/o/13edae/32.png) [@Oukile](https://boards.straightdope.com/u/Oukile)\ **Post date:** [December 9, 2008, 4:15pm UTC](https://boards.straightdope.com/t/why-do-pigeons-bob-their-heads/475847/18 "2008-12-09T16:15:02Z")
Funny how things happen some days. I was discussing with my boss and he just told me about this video of head stabilization in a chicken : [![](https://img.youtube.com/vi/_dPlkFPowCc/hqdefault.jpg "Chicken Head Tracking - Smarter Every Day") ](https://www.youtube.com/watch?v=_dPlkFPowCc) Doesn’t it beautifully illustrate our topic ?