Thomas County cat. [volume] (Colby, Kan.) 1885-1891, 1888-02-23
THE FLIGHT OF BIRDS.
An Anatomical View OF . Subject Fasc;x
atimg t. Lovers OF Mature

1
attractive than the soaring bird float
ing in mid-air. seemingly through
mere volition and independent of
known laws of motion. Mathematical
theories have been devised to solve
this riddle. Perhaps there is some
delicate action in the wing. some sub
tile manipulation of the great quilts
Chat are curiously shaped) which may
help to explain the matter. Such q
movement would escape the unpre-
pared observer. A glance at the an
atomy of the wing will make this the
DRY clearer and enable any one to
study the matter for himself. The
wing corresponds to the human
arm; it has the arm. forearm and
hand, with thumb. first and second
fingers. The first finger only is well
developed, having two or three seq
ments and is freely movable at the first
knuckle joint in the manner of the in
dex finger. If we raise the arm
straight out from the si'le of our body
with the palm down. this will be the
position of the spread WING. Now
moving the hand in the horizontal
plane from side to side, we initiate the
only motion that is possible in the
wrist joint of the bird; the birds hand
can be bent back against the forearm.
For convenience we may call this back
ward movement fleXion; the opposite
movement extension. The unfolding
or spreading of the wing is largely
automatic. As in man, the birds fore
arm contains two bones. radius and
ulna, the former supporting the hand
rs in man.
This action we can easily observe in
our own persons; the outer bone in the
forearm is the radius, and as the hand
is turned we can feel that bone turn
ing or rotating with it; the ulna does
not share in the motion. In the bird
this rotation would interfere with the
proper use of the limb the radius only
sides to and fro upon the ulna. This
sliding takes place as the wing is
spread through the mechanism of the
elbow joint; the radius gliding back
on the ulna drags the wrist bones and
hand over the end of the ulna in such
a fashion as to bring it from the flexed
into the extended position.
This extension is facilitated by the
pull of an elastic band that stretches
from the front of the shoulder to the
wrist, and forms the edge of the web
of the wing. as one may see in any
bird served on the table. All these
movements are inaugurated by a
strong muscle that pulls on the elbow
at the back of the arm. We can easily
feel this muscle act in our own arm
when we siraighten it. One can not
fail to admire the beautiful simplicity
of the mean through which so COM
plicated result is effected. Other
agencies than those described modify
the wing movements, but it is not
necessary to detail them here. One
point more. The quill feathers al
tached to the band are so arranged as
to enable us roughly to classify wings
under two great heads-broad and
narrow wings. In the broad wing.
when spread, those quilts (primaries)
form at their tips an oval outline.
Such wings are deeply concave. The
turkey. grouse. quail. have such wings.
In the narrow wing the primaries
form an angle, more or less acute.
with the point at the end of the
wing and in line with its axis when
spread. Birds of prey. gulls. swal-
lows, the large migratory birds are in
this class. These birds are much of
the time in the air, while those with |
broad wings are distinctly terrestrial
in habit. All are familiar with the |
flight of the quail or grouse; it springs |
with a startling rush from the ground,
is off like IA bullet, and finishes its |
course with fixed wings. whose con-
cave catches the air like parachutcs.
and so gradually sails to the earth. |
The bird of prey, on the contrary.
heavily struggles to leave the level. |
The buzzard may be captured rs it
clumsily flaps along to get the mo-
mentum necessary to launch itself into
space. but once afoat what poetry of
motion! No violent beating OF the
wings. no hurried scrambling in its
progress: in graceful gyrations it
circles overhead with the calm and
unconscious ease spirit might dis
play. The soaring or sailing of the
grouse is easily understood. but this
other is different matter. SUPPOSE
We turn to anatomy again. Ito pri-
mary quilts in the marrow wing have
a marked twist, increasing toward the
tip of the wing; this torn suggests the
blade of propeller. The white
pelican. soaring bird, has to each
wing five such quilts attached to the
'index finger" this. it will be remem-
bered. may rotate on its knuckle joint.
There are two muscles in the forearm
which send their tendons to this finger
and rotate it, so that its i've quilts may
describe q scuiling motion. Now. If
Al L.