The Relationship between Physical Build and the Hole John Emoto-Tisdale The hole – it is a myth to some, a lie to others, something I have never seen but seen by others, the highest mode of performance to some, an old surpassed standard to others, and an old beaten to death worthless topic to others yet. One thing it is not is a topic of consensus. Do I expect this article to change that? No way. Even if what I have to say here is true, my name, age, resume do not give me any credibility. There are also some of us (I am guilty sometimes) who are so sure of our own opinions that we listen to others by defending our own opinions, if we listen at all. *As sort of an aside: I would argue that there is not a single person past, present or future that has known ANYTHING with ABSOLUTE CERTAINTY – there is always an end to a person’s knowledge. “How do you know that to be true?” can ALWAYS be asked after a statement, and each answer to that question can be asked that same question: “how do you know that to be true?” At some point, the honest answerer must either admit they do not know, or resort to a lie to defend their previous statements. Therefore, all statements made prior to that point are possibly partially wrong, or wrong entirely. The reason we can go about our lives making decisions is because we either consciously or unconsciously choose to just believe certain things that we cannot know to be true, and then we build our logic on top of those things. Therefore, it is my opinion that the most accurate type of statements we can make are of this sort: “IF THIS OR THAT IS TRUE, it follows by this or that logic that this or that other thing is also true.” (***This aside may seem unrelated to this topic. I included it because our discussions about the hole and roller topics in general are so often unproductive – people often state an opinion as if it is definite truth, without questioning it and admitting that it could be wrong.) I will attempt to communicate my understanding of what physics’ current understanding of motion says about the possibility of our pigeons creating the illusion of a hole in their side while they are rolling. I KNOW A LOT OF PEOPLE GET TURNED OFF WHEN PEOPLE SPEAK ACADEMICALLY, because often the educated person thinks they know better than the non-educated person just because they can use and understand terms/jargon that the other can’t. I COULD NOT BELIEVE THAT TO BE FARTHER FROM THE TRUTH AND HATE THAT CONDESCENDING ATTITUDE THE EDUCATED OFTEN HAVE (I have been guilty myself)!!! Education and learning scientific jargon alone do not make that person more able to understand a real-life problem. However, it would be difficult to logically suggest that a true understanding of physics is not beneficial, because it is primarily our understanding of physics that opened the door for man to make things that would have been absurd magic to people in the not-so-distant past – huge metal things like airplanes and helicopters that fly in the sky, rockets/satelites/etc launched/navigated in space, smart phones and cars, etc. However, PHYSICS’ UNDERSTANDING of the universe is not entirely true or complete – physics is an evolving understanding that has taken twists and turns in the past, and seemingly must take more twists and turns in the present/future in order to explain things that it currently cannot. It is also possible that MY UNDERSTANDING of physics’ understanding as it relates to our pigeons rolling and the hole is wrong or incomplete to some degree. I welcome all questions in those regards. At some point I would probably have to say I don’t know, as would you. ***If, however, physics’ understanding and my understanding of physics’ understanding is accurate as it pertains to our pigeons creating the illusion of a hole, then the points explained in the rest of this article hold true as well. I think it would be fair to say most of us have seen shared on different online forums and in some roller publications either pictures or drawings of pigeons in the act of rolling with their head and tail rotated towards each other and the wings down (relative to the bird) like the one shown in Image 1. Often, the curved arc that the back, tail, and neck form with each other is enough for the author to claim that this bird must have showed the hole because the picture shows it doing so. It is understandable how our intuition might lead us to believe that the bird in Image 1 rotates around the arc formed by its neck, back and tail, but that CANNOT BE SO IF THE BIRD OBEYS THE LAWS OF PHYSICS. Consider a palm sized river rock. Flip it into the air. It rotates around a certain point inside of the rock. Now glue one end of a light flexible stick to one end of the rock. Bend the rest of the stick into a circle and attach the remaining end to the other side of the rock. Now the profile has a nice circular arc to it JUST LIKE PICTURES OF OUR BIRDS ROLLING. If you now flip it into the air, the rock/stick will NOT rotate around the center of that arc. Rather, they still rotate around almost exactly the same point within the rock that they did before adding the light stick. This is analogous to the arc that the very light tail and neck form around the heavy abdomen. Looking at the shape the bird creates misleads us in our attempt to understand its rotation. It is precisely for this reason that I will proceed by discussing this topic of the hole from the vantage point of physics, as the principles of physics disregard and are not vulnerable to errors of intuition. See Image 2 for schematic of the rock and rock/stick example. Take any object and toss it into the air with a flip of rotation. Invariably, it will rotate around an axis that passes through its center of mass. There are several physical principles from which this behavior is a necessary result – I will not include a deduction of this result from a physical principle, but you can easily find many such deductions on the Image 1: Picture courtesy of Dave Szabatura internet. The center of mass can be thought of as an object’s balancing point. Put your finger under an object in a location that allows it to balance – the center of mass is located at a point somewhere directly above or below where your finger is touching. How does the location of a pigeon’s center of mass affect its ability to show the hole? Well, since a pigeon can only create the illusion of a hole if it rotates around an axis OUTSIDE OF ITS BODY, it follows that the pigeon’s center of mass must also be located outside of its body during rolling. 2a: If flipped into air the rock will rotate around an axis that passes through the red star (center of mass of rock). 2b: If flipped into the air, the rock/stick will rotate around an axis that passes through the red star (center of mass of rock + stick). Image 2: Because the stick is so much lighter than the rock, adding the stick has very little effect on the location of the axis of rotation (the red star would be SLIGHTLY higher in 2b than 2a, even though that is not obvious in the images). The rock/stick would NOT rotate around the center of the arc that the stick creates. Where is the center of mass for a rolling pigeon? The position varies slightly from individual to individual, and also changes for each pigeon depending on where its moveable body parts (wings, neck/head, legs, tail, abdominal organs, etc.) are located. However, the center of mass for all birds during flight is located in the abdominal area somewhere behind and below the wing joint (see Image 3). This is a helpful condition for stable horizontal flight as evidenced by our airplanes, which mimic nature’s design. If the center of mass remained in that location (within the body) during rolling, the illusion of a hole could not exist – the blurred profile created by such a bird would just be a solid with no void. However, to our benefit, the head/neck and tail each move upward during the 3a – Suspended by a string, the center of mass 3b – Suspended from a different position, the roll, shifting the center of mass is located somewhere along the black line (in center of mass is located along the blue line slightly upward with them. For line with the string) marked on the pigeon. marked on the pigeon. fleeting moments of the roll during the wings’ upstroke, Image 3 – In its lifetime, this plucked pigeon was an excellent performer. Its center of mass is at the intersection of the black and blue marked lines. This location is denoted by the red star. the wings may also be located some amount above the back, which would also slightly shift the center of mass upwards. Unfortunately, the wings seem to mostly be extended downward during the roll, which shifts the center of mass downward with them. For the illusion of a hole to be possible, the effects of the upward moving body parts must be sufficient to shift the pigeon’s center of mass up above its back, outside of its body. However, because most of a typical pigeon’s mass is in the abdominal area, the effects on the center of mass position caused by movement of those light body parts are small just like the effect of adding the stick above the rock was. Dissecting a pigeon will confirm how little mass is in these upward moving extremities versus the majority of mass that is contained in the abdominal area (see rump/tail muscle, wing muscles, neck muscles in Image 3; see wing muscles, breast muscles, neck muscles in Image 4). Shifting the center of mass upwards above the back can be done in the following two ways: 1 – Reduce the mass of the abdominal area. A reduction in abdominal mass increases the effect the moving extremities have on the center of mass position. This can be accomplished by reducing the depth, length, and width of the abdominal area. Think shallower keels, shorter from front of chest to end of back, narrower up front at shoulders and narrower towards the end of back/vent 4a – Plucked wing, feathered body 4b – Plucked and skinned for clear view of muscles Image 4 – The wings are mostly feathers, which are extremely light compared to the abdominal area. The bones and muscles under the wing feathers are also tiny. The neck muscles visible in 4b are also very small. area. 2 – Increase the mass of the moving extremities so that they have a greater effect on the center of mass position. There are several different combinations of the two described strategies that can be implemented. However, if taken too far, there are negative effects to anticipate from each of those strategies. For instance, decrease the abdominal mass too much and that bird will no longer have sufficient muscle to fly well or propel itself to a great enough rotational speed to create the blurred profile necessary to show the contrast of a hole (without a solid profile for there to be a hole in, the concept of a hole does not make sense). Another negative effect would be a bird with such a massive neck/head that the bird cannot keep the neck/head positioned upward during a high velocity roll as too much force is required to do so. That inability to hold the neck/head upwards prevents the extra mass added to the head/neck from accomplishing its intended purpose of shifting the center of mass position upwards. Perhaps there are birds that, as claimed, have shown the hole in the past, or that show the hole today. If so, it must be true that the upward movement of their extremities during rolling was/is sufficient to shift their center of mass up above their back. People who claim some bird has shown a large hole (some have claimed a 2 inch hole!) are probably mistaken, because this would require an incredibly more difficult task than it already is for a bird shift its center of mass upward enough to just pop out above its back. It is also worth pointing out that even if a bird were to shift its center of mass a large amount above its back, the pigeon would probably not be able to rotate fast enough to create a blurred profile, because the amount of torque generated by the wings to do so increases GREATLY (it can be deduced through physical principles that the torque necessary to rotate a bird around an axis an inch above its back, which is the amount necessary to show a 2 inch hole) would be nearly 4 TIMES greater than the torque to rotate around an axis located just above its back). A smaller hole is much more believable, as it does not require such a large shift of its center of mass location (though the smaller the hole is the more difficult it is to actually see it!) What these people claiming a large hole are likely observing is a pigeon not rotating fast enough to create a blurred profile, but rather a large falling/rotating U shape and mistaking the empty space in the U as a large hole. I generally ask to physically see and handle any bird that someone claims showed the hole, or, if it’s an online discussion, I ask to see a picture of the bird. If the bird has an extremely heavy abdominal area (deep keel, wide chest/torso), I am even more skeptical of the claims than I would have otherwise been. It is likely true that the physical build optimal for maximum rotational speed is not the same as the physical build optimal for showing a hole. Getting a bird to show the hole seems to me the more complicated juggling act as the bird must not only have a physical build that will result in its axis of rotation being outside of its body, but it must also be capable of rotating fast enough to create a blurred profile. I am not sure if it is possible, but I am captivated to pursue this hole with my birds. The bird optimized for maximum rotational speed also greatly allures me. As I close, I must clarify that I do NOT suggest physical build is the most important or only consideration necessary to obtain certain performances – the manager’s conditioning/training of his/her birds, neurological traits and other traits/genes unobservable to us (without sophisticated scientific equipment) are arguably just as important, or more so, than the physical traits. Best of luck to you all with these amazing creatures.