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This is a question I’ve often wondered. The way pigeons walk was the first thing that attracted me to them when I was a little girl. I love the head-bobbing and strut of a pigeon. It entertained me endlessly while I would wait for a bus to take me home after school.

Firstly, I want to explain what the so-called “head-bobbing” movement really is. It is characterised by a rapid forward movement, called the thrust phase, which is followed by a hold phase. The backward movement is in fact an illusion. As stated by Necker (2007) “the head position is kept stable with regard to the environment while the body moves continuously forward. In this way head movements during walking are characterized by a hold phase and a thrust phase.”

So in layman’s terms: as a pigeon walks it thrusts its head forward and holds it while its body walks past that point and the pigeon then thrusts its head forward again. To us this looks as if the pigeon is moving its head forward and backward as it walks.

Most birds, pigeons included, have poor stereoscopic vision or depth perception (pigeons have lateral eyes with only minor binocular overlap). So, “during the hold phase [of the head-bob] the image of the surrounding world is stabilized for a short while on the retina, which increases the time to recognize and identify objects, especially moving ones” (Necker, 2007).

I think Wedderburn (2009) put it nicely when explaining why pigeons head-bob: “…it allows them to more clearly observe their surroundings for predators. The relative head holding phase provides a more stable picture; it would be far more difficult to identify very subtle movements of a cat if the bird’s eyes were moving relative to their surroundings.

“The head bob offers another advantage to birds: since their eyes are on either side of their heads, they have little binocular overlap (where both eyes can see the same object) resulting in poor depth vision. When head-bobbing, objects further away will seem to move more compared to objects that are close-up. … This is called ‘motion parallax’ and it allows birds to judge distances more effectively.”

The head-bob is not just a pigeon thing. Other species do it too.

The Orders of head-bobbing and non-bobbing species (well known species in brackets).

Head-bobbing: Columbiformes (pigeons, doves), Galliformes (chickens, pheasants, quails, peafowl), Gruiformes (cranes, rails) and Ciconiiformes (herons, storks, ibis).

Non-bobbing: Sphenisciformes (penguins), Phoenicopteriformes (flamingos), Pelicaniformes (pelicans, cormorants), Anseriformes (ducks, geese, swans), Falconiformes (hawks, eagles, vultures), Strigiformes (owls) and Psittaciformes (parrots, cockatoos, budgerigar).

Mixed: Charadriiformes (gulls, plovers, puffins) and Passeriformes (crows, starlings, sparrows).

Please go to the following website for more details on head-bobbing. It has videos and graphs to explain head-bobbing: Head-bobbing of walking birds – a review

It is not really known yet why some species head-bob and others do not.

The following publications are an interesting read, but good luck as a few are quite long! :)

Another interesting article on head-bobbing:

Why do hens and pigeons walk with bobbing heads?

By Pete Wedderburn

Last updated: June 25th, 2009

When I met a specialist  in biomechanics at a social function recently, I asked him if he knew the answer to a puzzle that has intrigued me for years: why do some birds bob their heads backwards and forwards as they walk? Pigeons and chickens are the best examples of this odd behaviour. Were their necks connected by sinews to their legs? What was going on?

He had no immediate answer for me, but like all good scientists, he has an appetite for knowledge and the determination to find the truth. He did some research, and this week, he sent me an email that explains what’s going on with this head-bobbing birds.

The subject was analysed by a Canadian scientist in 1978, using a high speed camera to measure the movement of a pigeon’s head, breast, wingtip and foot, when: (i) walking on the ground, (ii) when walking on a treadmill, and (iii) when being carried by a person who is walking along.

Firstly, by closely examining the bird walking on the ground, he confirmed the precise nature of the movement involved. This rhythmic action of the head bob involves a rapid forward ‘thrust’ of the head and what appears to be a slower backward movement. However, the backward movement of the head is an illusion, as the head in fact stays stationary relative to the bird’s surroundings, while the body actually ‘walks past it’. This backward moving phase would be better described as a ‘relative head-holding’ phase, where the head is held (almost) stationary relative to the bird’s surroundings.
When the pigeons walked on a treadmill (which must have taken some time to train) the head bobbing stopped, since the pigeon’s body was not moving relative to its surroundings.

When the person carried the pigeon while walking, the thrust and relative head-holding phases reappeared as the pigeon was again moving relative to its surroundings.
Other scientists took this work further, training birds to walk on the ground when blindfolded. These birds did not bob their heads, further confirming that the head bob is prompted by seeing the surrounding environment moving relative to the bird.

So why do birds use this thrust and relative head-holding action? The best guess is that it allows them to more clearly observe their surroundings for predators. The relative head holding phase provides a more stable picture; it would be far more difficult to identify very subtle movements of a cat if the bird’s eyes were moving relative to their surroundings.

This is easy to show. Ask a willing assistant to stand with a bright object in their hand (representing a predator) while you stand 10m away. See if you can detect when your assistant moves the object just a few centimetres (about 5 cm is observable). Ask them to repeat this while you are running parallel to them and you will see it is nearly impossible to identify when the bright object is being moved this small amount.

The head bob offers another advantage to birds: since their eyes are on either side of their heads, they have little binocular overlap (where both eyes can see the same object) resulting in poor depth vision. When head-bobbing, objects further away will seem to move more compared to objects that are close-up. (Try holding your finger in front of you and move your head from side to side, and you’ll see what I mean.) This is called “motion parallax” and it allows birds to judge distances more effectively.

I thought that it would impress readers if I could duplicate the scientific research in my own back garden, so last night I took some video footage of one of my own hens walking on her own, then being carried by my daughter.

It’s a good demonstration of the walking head bob, but it’s less easy to see the bob when the bird is being carried.

Scientists are willing to study anything; they are sometimes driven simply to understand, even if there appears to be no real benefit to us. And now you too know why hens use that much-mimicked head-bobbing chicken-walk.


There are currently around 318 species of pigeons and doves in the world. Many are threatened with extinction and already many species are extinct. 

There are two websites I would like to highlight.

The first is called The Sixth Extinction, a website about the current biodiversity crisis, which is an educational site highlighting the plight of many species and aiming to bring this to the attention of the public. With more people aware of the problem then maybe more people will help (in ways explained in: Stop Extinction! How Can You Help?). The site also contains lists of globally extinct animals (and the list of birds: Globally Extinct: Birds).

It is so scary and very sad how quickly animals are disappearing – many without anyone even knowning anything about them – they are gone before discovery! Awareness of the problem is the first step, with Action a quick second.

The second website is called Columbidae Conservation, a UK based charity working towards the conservation of pigeons and doves, as well as their habitat, around the world.

The site contains news about conservation efforts, as well as publications on scientific studies (e.g. ecological, behavioural) about different pigeon species.

The following map from the website shows the distribution of pigeons and doves (click on the maps to make them bigger):

And the distribution of extinct and vulnerable species:

More about the above maps at: http://www.columbidae.org.uk/Columbidae%20Conservation%20index.html

I found various sites that have lists of extinct pigeons, however, none seemed to have the same amount of species, so please don’t treat the following list as gospel – it’s just what I’ve put together from the various sites:

Extinct pigeon and dove species

  1. Bonin Wood Pigeon Columba versicolor
  2. Dodo Raphus cucullatus
  3. Huahine Cuckoo-dove Macropygia arevarevauupa
  4. Liverpool Pigeon Caloenas maculata
  5. Mauritius Blue Pigeon Alectroenas nitidissima
  6. Norfolk Island Ground-dove Gallicolumba norfolciensis
  7. Passenger Pigeon Ectopistes migratorius
  8. Red-moustached Fruit-dove Ptilinopus mercierii
  9. Réunion Pigeon Columba duboisi
  10. Rodrigues Pigeon Alectroenas rodericana
  11. Rodrigues Solitaire Pezophaps solitaria
  12. Ryukyu Pigeon Columba jouyi
  13. Solomon Island Crowned Pigeon Microgoura meeki
  14. St. Helena Dove Dysmoropelia dekarchiskos
  15. Tanna Ground-dove Gallicolumba ferruginea
  16. Thick-billed Ground Dove Gallicolumba salamonis

Subspecies

  1. Lord Howe White-throated Pigeon Columba vitiensis godmanae
  2. Madeiran Wood Pigeon Columba palumbus maderensis
  3. Norfolk Island Pigeon Hemiphaga novaeseelandiae spadicea

The following article is from: http://www.sciencedaily.com/releases/2008/06/080613145535.htm

It is a very interesting read on self-recognition in pigeons.

Pigeons Show Superior Self-Recognition Abilities To Three Year Old Humans

ScienceDaily (June 14, 2008) — Keio University scientists have shown that pigeons are able to discriminate video images of themselves even with a 5-7 second delay, thus having self-cognitive abilities higher than 3-year-old children who have difficulty recognizing their self-image with only a 2 second delay.

Prof. Shigeru Watanabe of the Graduate School of Human Relations of Keio University and Tsukuba University graduate student Kohji Toda trained pigeons to discriminate real-time self-image using mirrors as well as videotaped self-image, and proved that pigeons can recognize video images that reflect their movements as self-image.

Self-recognition is found in large primates such as chimpanzees, and recent findings show that dolphins and elephants also have such intelligence. Proving that pigeons also have this ability show that such high intelligence as self-recognition can be seen in various animals, and are not limited to primates and dolphins that have large brains.

Experimental method and results

The pigeon was trained to discriminate two types of video images in the following method. First, live video images of the present self (A) and recorded video images of the pigeon that moves differently from the present self (B) are shown. When the pigeon learns to discriminate these two images, the video image of (A) is shown with a temporal delay, so that the monitor shows the image of the pigeon a few seconds before. If the pigeon remembers its own movements, it can recognize it as self-image even with the delay.

The pigeon could discriminate (A) with a few seconds delay as something different from (B). This shows that the pigeon can differentiate the present self-image and the recorded self-image of the past, which means that the pigeon has self-cognitive abilities. Video image (A) matches with the movement of itself, whereas (B) does not. Being able to discriminate the two means that the pigeon understands the difference between movements of itself and movements of the taped image. In this experiment, movements of the pigeon itself are in question instead of the mark of Gallup’s mark test (see 2-(1) below for explanation). When there is a temporal delay in the image of the present self, the longer the delay, the more pigeon’s discrimination was disrupted, and this also shows that the pigeon discriminates the video images using its own movements. The important thing is whether it understands the difference between movements in the video image that match with itself and movements in the video image that don’t.

Method of testing self recognition on animals

(1) Gallup’s mirror test (self-recognition test)

The self-recognition test on animals using mirrors was developed by psychology Prof. Gordon Gallup Jr. at the State University of New York, Albany. His papers released in 1970 in the “Science” magazine explaining that chimpanzees have abilities for self-recognition attracted attention. This test is known as the first to test self-recognition on animals. He anesthetized chimpanzees and then marked their faces. When the chimpanzees were awakened, they were confronted with a mirror and they touched the corresponding marked region of their own faces. Most tests of self-recognition are a variation of the Gallup test, and are used to assess self-recognition in a wide variety of species. It is also called the mark test, or the rouge test.

(2) Assessment of self-recognition on pigeons

Self-recognition can be assessed with cross-modality matching. A typical example of cross-modality matching is waving your hand when you see yourself in a video image. With a mirror image or video image of oneself, when information of the propriocepter (how the arms and legs of oneself are moving) and visual information of oneself correlate, this can be considered self-recognition. The Gallup’s mark test is based on the precondition that the subject can touch itself. Unless the subject touches itself, it cannot be proved that it has abilities for self-recognition. However, the test conducted on pigeons is more advanced, as it is based on how the pigeons move, and by memorizing the shown images, pigeons proved that they have self-cognitive abilities.

Self-cognitive abilities tested in pigeons are higher than that of 3-year olds

Through various experiments, it is known that pigeons have great visual cognitive abilities. For example, a research at Harvard University proved that pigeons could discriminate people photographs from others. At Prof. Shigeru Watanabe’s laboratory, pigeons could discriminate paintings of a certain painter (such as Van Gogh) from another painter (such as Chagall).

Furthermore, pigeons could discriminate other pigeons individually, and also discriminate stimulated pigeons that were given stimulant drugs from none. In this experiment, pigeons could discriminate video images that reflect their movements even with a 5-7 second delay from video images that don’t reflect their movements. This ability is higher than an average 3-year-olds of humans. According to a research by Prof. Hiraki of the University of Tokyo, 3-year-olds have difficulty recognizing their self-image with only a 2 second delay.


Journal Reference:

  • Toda et al. Discrimination of moving video images of self by pigeons (Columba livia). Animal Cognition, 2008 DOI: 10.1007/s10071-008-0161-4