Uploaded by John Tisdale

Relationship Between Physical Roller Pigeon Build and the Hole Illusion

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
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.
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.
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