THE STRUCTURE OF THE BIRD.
Let us now consider the bird’s bodily structure. Every child knows that
the bird’s body is covered with feathers or down, and that what, in the
case of mammals are fore-feet, in birds are wings with which they fly.
There are as many kinds of flight as there are kinds of birds. It
depends for the most part on the nature of the bird, in a smaller degree
on the structure of the wing.
The wing of the Swallow (Plate VIII._a_) is pointed like that of the
Peregrine Falcon, and is adapted for rapid flight. Both these birds
secure their prey on the wing, and could not, therefore, live otherwise.
The wing of the Partridge is, on the contrary, rounded; this bird does
not cut through the air, but can only raise itself in flight with rapid
fluttering of the wings, and with a sudden loud “whirr” which makes
considerable noise if the covey is a large one. The wing of the
Partridge, therefore, is not at all adapted for enabling the bird to
catch its prey flying, but only for moving from place to place, where it
picks up its food walking.
From this we learn that the various kinds of wings correspond to various
ways of flight and that each bird works out its destiny in its own way.
It is suggestive of the organisation of an army, composed of cavalry,
infantry, artillery, and other divisions. These also have different
kinds of functions, which are necessary both
[Illustration: (_a_) SWALLOW’S WING; (_b_) THAT OF THE PARTRIDGE.]
individually and in combination, and the one cannot supply the place of
the other.
So much for the wings. Now we will examine Plate IX., which shows heads
and--what is the most important part of them--bills. We will take the
illustrations in their proper order.
1. The bill of the Woodcock is shaped like a turner’s auger, the end
greatly resembling the tip of a finger. With this the bird gropes for
its food, and draws it out of the loose earth.
2. The bill of the Merganser has a hook at the point; it is toothed at
the side, and is so well adapted to its purpose that no fish, however
slippery, can escape.
3. The bill of the Hawfinch is conical, thick and strong, capable of
cracking the hardest cherry stones.
4. The pretty Water-Wagtail has an awl-shaped bill, formed by Nature for
the catching of gnats and other insects.
5. The Grey Heron has a bill which cuts like a knife. Woe to the most
slippery tench if once caught within it!
6. The Curlew penetrates into the mud with its sickle shaped, slightly
curved bill, and brings out of its depths the worms it feeds on.
7. The bill of the Long-tailed Tit is but a little point compared with
those mentioned above, but all the same it is quite suitable for the
bird, for only with such a tool could it pick the tiny insects out of
the smallest cracks in the boughs.
8. The bill of the Goatsucker or Night-hawk is small, but the opening of
the mouth is comparatively gigantic: it forms a yawning abyss, which, in
the twilight and darkness of night, engulfs unwary insects.
[Illustration]
9. The bill of the Woodpecker may be compared to the adze which the
Carpenter uses for chipping beams of wood. It is only by means of hard
blows that this bird can get at the worms which it finds in decaying
wood.
10. The Duck’s bill, on the other hand, is flat toothed at the side,
exactly formed for straining the food which it gets out of the water.
11. The bill of the Gull is so formed that it can easily take up food
from the surface of the water. Where Gulls arrive in large flocks, they
eagerly follow the plough in the fields, and are then of great benefit.
12. The bill of the Crossbill is a valuable tool, with which he is able
to pick out the seeds from between the scales of the fir cones.
13. The Ortolan splits hard seeds with the arch and the notch in its
beak, as it were with nut-crackers.
14. The bill of the Avocet is in shape the opposite of the Curlew,--that
of the former curving upwards, of the latter downwards.
Thus we see that as with the wing, so with the bill,--each bird is
furnished with the kind that is most suitable to its nature and habits.
The general law of adaptability to its purpose is also strikingly
exemplified in the formation of the foot. Let us look at Plate X.
1. The foot of the Fieldlark has a spur-like nail on the back toe which
is nearly straight, so that the bird can easily rest on the ground.
2. The Pheasant’s foot is just like that of the Hen; which enables it to
walk and run.
3. The powerful, sharp claw of the Eagle strikes deeply into the flesh
of its prey and holds it fast.
[Illustration]
4. The Sparrow Hawk strangles and crushes with its warty toes the birds
on which it preys.
5. The foot of the Owl, as well as its bill, proves that it is a bird of
prey.
6. The foot of the Swift is so constructed that it can cling to walls;
it cannot walk or stand.
7. The toes of the Moor-or Water-hen are provided with skin-flaps, not
altogether perfect for swimming, but excellent for wading and diving.
8. The Crested Grebe excels in diving, pushing sideways with its feet.
9. The foot of the Bustard has three toes, and hard soles, which enable
it to run extremely well.
10. The four toes of the Cormorant are joined together by a web; it is a
good diver, can swim under water, and can also roost on trees.
11. The Wild Duck has only three toes webbed together; its foot is,
therefore, specially suited for propelling the bird on the surface of
the water.
12. The toes of the Avocet are only partially joined together by webs;
its legs are suitable only for wading, but can be used for swimming in
case of need.
The variety and suitability to their purpose of wings, bills, and legs,
show us that the feathered inhabitants of a neighbourhood form a
community. A society of men would not be perfect if there were only men
of one calling. A variety of workers is needed in human society, with a
variety of tools, with which to perform a variety of necessary work,
just as various birds with a varied construction of body perform their
work in the open field of Nature.
* * * * *
A few words as to the feathers of the bird. The perfectly developed
feather consists of a quill which grows in the flesh, the stem becoming
gradually thinner towards the top and having lesser feathers on either
side, those on the one side of the
[Illustration]
quill being narrower than those on the other half. The feathers overlap
each other exactly and densely especially those which protect the main
part of the body. At the end of the quill of the top feathers is a down
which takes the place of our under-clothing, and which in the case of
waterfowl prevents the water from penetrating to the body of the bird.
There is also a pure down which is composed of numerous stems; this is
close and thick and protects the binding together of the general
plumage.
[Illustration]
The down has its fine quill and a stem bearing the close down which in
water fowls keeps the warmth of the body at an even temperature whether
in or out of the water. It would be an error to suppose that the
feathers grow in the skin without any order, simply close together. They
are in point of fact divided into areas between which the flesh is
generally covered with down, and all is arranged in a system of
grouping which, the feathers being rightly placed over one and another,
does not in any way interfere with the movements of the body, each
movement being in perfect conformity with this feather covering. The
feathered areas can be moved independently with the aid of the muscles,
and this renders the cleansing of the individual feathers easy and the
removing of the fatty substance, which is a matter of great importance.
If we watch we see that the bird moves the feathers separately in this
cleansing process, drawing them through its beak, and so removing any
bits of fat and oily substances that may have collected about the fat
glands.
[Illustration: View of the back of the bird, showing the feather tracts.
The spaces between the tracts are covered with down.]
[Illustration: USEFUL.
THE BARN OWL, CHIEF OF THE MOUSE-HUNTERS.]