Author: Nick Stockton. Date of Publication: 01. 20. 15. 01. 20. 15
Time of Publication: 6:45 am. Pigeons get a bad rap, but they are one of my favorite species of bird. The only thing that irks me is the way they go around picking up bits of peoples leftover lunches. I m not condemning their dietary choices (who am I to judge? ), it s just thatВ I always felt like they d get a lot more respect if they stopped that ridiculous head bobbingВ while scavenging for food. Because their primary mode of transportation is flight, I figured pigeons needed to bob their heads to keep from tipping over while waddling after hot dog nubs. In reality, it has nothing to do with their sense of balance, but everything to do with the way they see the world. What the head bobbing lets pigeons do is momentarily fixate their eyes on objects. This gives the photoreceptors in their eyes enough time about 20 milliseconds to build a steady sceneВ of the sidewalk world. And this has nothing to do with their bird-size brains. Vision doesn t mix well with movement. All animals, from insects to eagles, have. Many mammals, humans included, do this with slight twitches of the eye. This is instinctual, and comes from neuromuscular connections between our eyes and the part of your brain that tracks movement and rotation. Pigeons are able to move their eyes, but their longer, more flexible necks make it more efficient for them to do this motion tracking with their necks.
We know this because in the 1970s a group of researchers (covered with a plexiglass box, so the birds couldn t fly away) and observed that their heads did not move when their surroundings were stationary as they walked. Your eyeball instinctively tracks the world as you move. Otherwise most things would be a blur. Which brings me back to bobbing, which isn t actually what pigeons are doing. Instead, as they move, their heads (and eyes) lock in place while their body catches up. Then the head darts forward again, locks onto something new, and the pigeon s body keeps moving forward. In the same study as the treadmill experiment, researchers filmed pigeons in their natural environment. Then, frame-by-frame, they analyzed the movement of the birds head, feet, and bodies and confirmed that the head bob В was an illusion. Of course, plenty of other birds jerk their headsВ as they walk, notably chickens. And other experiments (which included putting blindfolds on chickens, or locking them in a dark room) have shown that many species use head movements to track their surroundings. They also foundВ that the head bobbing was instinctual, and emerged within 24 hours of hatching. Alas, learning this hasn t done much to improve my opinion of pigeons dorky gait. Then again, pigeons don t have the reciprocal benefit of judging me every time I trip on my way to the refrigerator.
Why is it that pigeons bob their heads so vigorously when they walk? Like most prey animals, pigeons have eyes on the sides of their heads. They \’bob\’ so that each eye sees two nearly simultaneous views and can thereby give an approximation to binocular vision. You can try this yourself by covering one eye and moving your head from side to side. If you like, you can go \”coo coo\” at the same time. They have their scarves tucked into their belts! It\’s the result of mobile phone radiation. It\’s to keep their vision steady as it compensates for up and down movements in their bodies when they walk. Pigeon style bobbing involves them keeping their heads in the same position, relative to the world around them, for as long as possible, thus affording them the maximum opportunity to spot predators and/or food. If it was to get an approximation of binocular vision, they\’d carry on bobbing when they stood still, which they don\’t. Instead they move their heads from side to side. Have a guess what that\’s for. I have always assumed that pigeons, like chickens, do not have sufficient brain capacity to process moving images. The head is not bobbing, but moving from one fixed point to another and recording a series of stills. Try gently chasing a pigeon – its head will speed up as it walks faster. This desire to keep the head in one place can be demonstrated by holding a chicken and moving it from side to side and up and down.
The head stays where it is. This even works if the chicken is turned upside down, until, of course, its neck can stretch or bend no more. The limited brain capacity also means that the bird is unlikely to retain any psychological scars from this experiment. The intent for still images is not dissimilar to an ice skater or dancer spinning but keeping the head in the same position as long as possible. The pigeons are actually trying to keep their head a stationary as possible. This allows better assessment of their surroundings and threat detection. The head occupies one position whilst the body moves beneath it. After the next step has been taken the head rapidly moves to its next stationary position letting the body catch up and, again, move beneath it. I agree with Nick of London. They do this to detect movement around them. This ensures that when you approach these \’flying rats\’ they can take off at the last second, straight into your face, thereby contaminating your with filthy germs and bacteria. I blame this phenomenon on Ken Livingston for not providing enough buses so that we don\’t have to walk through the little blighters in the first place. So they can walk, The bobbing momentum keeps them moving, much like a clockwork mouse. Because they have all seen \”Shaft\” and thought he was cool!