try to know exactly how birds are made have found out that birds' eyes
make everything look much larger than it is, in other words, they are
like magnifying glasses, or microscopes, so that a tiny insect egg, that
we can hardly see, looks very big to a warbler.
Stranger still, when a bird is far off, his eyes are like telescopes.
That is, when a hawk is soaring about far above the earth, he can see a
mouse on the ground as well as if he had a telescope to look through.
And the gulls who sail about over the shore, and follow steamers on sea
voyages, can see small fish and tiny bits of bread thrown out by the
passengers, even when they are lost to us in the foam made by the
vessel.
Mr. Frank Bolles had a pet barred owl, and used to take him out with
him. He says that the bird's sight was wonderful, better than his own
aided by a strong glass. Many times the bird would see and watch a hawk
so far off that Mr. Bolles with his glass could not see him until he
came nearer, and then he looked no bigger than a dot against the sky.
There is a story told of some small birds migrating over the island of
Heligoland, suddenly coming down in a flock on to a man's garden, and
beginning at once to work among the leaves as if they were feeding.
The owner of the garden knew they did not eat leaves, so he shot a few
and found them stuffed with small caterpillars. Then he looked at the
plants and found many more caterpillars, each in the curled-up end of a
leaf. The insects could not be seen, yet the birds, while flying over,
no doubt saw the curled leaves and knew they were there.
Such eyes must be of great use in helping birds to find their food, and
to avoid their enemies. But think what giants we must look to them! It
is no wonder they are afraid of us.
Perhaps even more useful to a bird than his eyes are his ears, though
they are so nicely covered up by the feathers that we cannot see them.
The tufts of feathers that stand up on some owls' heads, and are called
ears, are not ears at all, but merely decorations, like the crests of
some birds and the long tail feathers of others.
But because they cannot be seen, we must not think birds have no ears;
they have very good ones indeed. They can hear much better than we can.
Every one has seen a robin run over the grass and turn his head one side
to listen. It is supposed that he hears the earthworm move under the
sod, and if he is watched, he will often be seen to pull the worm from
that very spot.
When a woodpecker taps on a tree trunk and turns his head to listen, it
is thought that he hears the grub stir under the bark, for when he
begins to cut the bark away, he is pretty sure to find and draw it out.
Birds that are much hunted by men, like ducks and geese, get to be very
knowing, and show how wonderful is their hearing. They can tell the
difference between a noise made by an animal and that made by a man. A
deer or any animal may crash through the bushes, and they pay no
attention to it, but if a man makes the least sound they are off in an
instant.
A bird's ears are behind the eyes, and a little below them. They are
covered by delicate feathers that hide them from sight. When the bird
raises these feathers--perhaps to hear better--they look like tiny ear
muffs.
Owls have little flaps of skin with which they can shut up their ears
when they wish to be quiet. This must be very useful to birds who prefer
to sleep during the day, when nearly everybody else is awake and making
a noise. Many of us who live in cities would like to be able to close
our ears sometimes.
Mr. Bolles tells a story about the sharp hearing of a heron. The bird
was on a tree dressing his plumage, and he was hidden in some bushes and
could not be seen.
Mr. Bolles made all sorts of noises to start up the heron and make him
fly. First he imitated animal sounds. He quacked, and barked, and mewed,
and brayed, and the bird looked interested, but not at all alarmed. Then
he whistled and sang, and at last talked plainly, but the bird only
looked over his way, as if to see what new sort of beast was hidden
there.
No noise that he could make startled the heron in the least, until a
twig snapped under his foot, when the bird was off like a shot. That
sound he well knew was made by his most feared enemy, man.
XXIV
HIS FEET AND LEGS
A BIRD always stands on his toes, not on his whole foot, as we do. The
long slim part that we call the leg is really the foot, and the joint we
see nearly up to the bird's body is the bird's heel. But in this book we
will speak of it in the common way, calling the toes the foot, and the
part up to the joint the leg.
People all over the world have the same kind of feet and the same number
of toes; but with birds it is not so. Most of them have four toes (Fig.
8), but some have only three, and a few have no more than two.
[Illustration: FIG. 8.
Foot of Blackbird.]
In the use of the feet there is still more variety. There are, as Dr.
Coues divides them, three kinds of feet among birds:--
[Illustration: LESSER YELLOWLEGS]
First, a foot that can be used like a hand to clasp a perch, a "perching
foot."
Second, one that is good to use as a foot, but not at all like a hand,
called a "scratching foot."
Third, one that is like neither hand nor foot, but a paddle, called a
"swimming foot."
The birds who have the first kind, the "perching foot," have usually
three toes turned forward and one turned back. They can grasp a branch
or a twig as tightly as if with a hand, as all our common little birds
do. And the large birds of prey, such as hawks and owls (Fig. 9), hold
in them live mice and squirrels and the other little animals they eat.
[Illustration: FIG. 9. Foot of Hawk.]
Some birds with perching feet have the toes placed another way.
Woodpeckers have two turned forward and two turned back, so that they
can hold better to a tree trunk (Fig. 10).
[Illustration: FIG. 10. Foot of Woodpecker.]
A strange thing about the perching toes is the way they are made to hold
on, so that the birds can sleep on a perch, and not fall. Inside the
toes are tendons, something like cords, which act like elastic
rubber. When a bird bends his leg, the toes are drawn up and held so.
When he is sitting on a perch, he could not fall off if he wanted to.
Birds who have the "scratching foot," the second kind, mostly go about
on the ground, or wade in the water. They do not usually sleep on
perches, but sleep standing, or crouch on the ground. In the arctic
regions, where there is a great deal of snow, some birds with scratching
feet, who have to go about in it, have in winter what has been called
"snowshoes," because it enables them to walk on the snow with ease. It
is a web-like growth on the side of each toe, which serves the same
purpose with birds that snowshoes do with men, keeps them from sinking
into the snow.
Birds who have the "swimming foot," the third kind, have the toes made
into a paddle by webs stretched between them. They are the water
birds,--ducks, geese, gulls, and others.
The toes of all birds have long, sharp claws, not at all like our
toe-nails. In the whip-poor-will and the nighthawk, one edge of the
middle claw has teeth like a comb.
The long slim part above the toes, what we call the leg, is named in the
books the "tarsus." The tarsus is generally bare, with a leathery skin;
but in some hawks and owls it is covered with feathers. Birds who live
away up in the cold have feathers down on to the toes.
On looking carefully at one of these bare legs, it will be seen that it
is not smooth like a lead pencil. It is marked in a sort of pattern.
Different species of birds show different patterns. Some look like the
shingles on a roof; others like little squares or plates; and some are
finer, like scales on a tiny fish.
These marks help in arranging birds in the books. That is, all who have
the same pattern are said to be related.
The legs of birds are not all of the same length for their size. Some
who never go about on the ground, like hummingbirds, swallows, and
swifts, have very short legs. Birds who walk and hop on the ground have
them longer, and birds who wade in the water have the longest of all.
XXV
HIS WINGS AND TAIL
A BIRD'S wing does not look much like our arm and hand, yet the bones
show that they are the same. The bird has a shoulder, elbow, and wrist,
as we have. He even has fingers, though they are so covered up by
feathers that one would never know it. He has not so many fingers as we
have, and they are not movable like ours.
A bird's wing is a wonderful flying-machine, which men have been trying
to imitate these many years. It is made of long stiff feathers, which
fold down smoothly over one another at his side when he is resting, but
can spread in an instant into a broad fan, to beat the air and carry him
away.
One would not think that feathers could have so much power; but when the
wing is spread, the barbs of the feathers hook together with tiny hooks,
so small a microscope is needed to see them; and that, together with the
edges lapping over each other, makes them almost like one solid
surface.
Wings are not alike in shape. The wing of a swallow is long and narrow,
while that of a hen or grouse is short and round. We can tell by the
shape of a wing how a bird flies.
A long, narrow, pointed wing shows that the bird has an easy, skimming
flight,--either he flies great distances, or spends hours at a time on
wing (Fig. 11).
[Illustration: FIG. 11.
Wing of Swift.]
The short round wing (Fig. 12) shows that a bird has a strong flight for
short distances. These wings are found mostly on rather heavy birds,
like grouse.
[Illustration: FIG. 12.
Wing of Sparrow.]
The longest wings are seen on water birds, such as the petrel and the
frigate-bird. The shortest, also, are found among water birds, those who
swim more than they fly, as the auks.
All the feathers of the wing are named, and it will be well to remember
that the long stiff quills are called _remiges_ or "rowers." These are
firmly rooted in the flesh, and are the hardest to pull out. They are
the most important to the safety of the bird.
Birds have also another use for their wings. They are a strong weapon to
defend themselves, or to fight others. A large bird can give a severe
blow with his wing, and when pigeons fight, it is said they hold up one
wing to protect themselves while they strike at the enemy with the
other.
Sometimes wings serve as musical instruments. Woodcocks make whistling
sounds with their wings as they fly, and mourning doves softly murmuring
ones. Ruffed grouse produce with theirs a rolling drum-like effect, and
others rattle theirs like castanets.
[Illustration: FIG. 13.
Tail of Ruffed Grouse.]
If wings are not used, they slowly get to be smaller and weaker, each
generation having them more and more useless, till after a while they
are of no use whatever, and the birds cannot fly at all. This has
happened, it is supposed, to the ostrich family and to some birds living
in the sea.
[Illustration: BROWN THRASHER]
[Illustration: FIG. 14.
Tail of Vireo.]
The tail of a bird is formed of an equal number of feathers in pairs,
most often twelve. When spread they are the shape of a fan (Fig. 13),
and when closed they lie over each other with the middle pair on top.
[Illustration: FIG. 15.
Tail of Swallow-tailed Kite.]
The tail feathers are not always of the same length, and that makes a
difference in the shape of the end. Sometimes they are even (like Fig.
14), when the tail is said to be "square." Sometimes the middle feathers
are a little longer than the outside ones, and then it is "rounded"
or "pointed." If the outside feathers are longest, the tail is "forked"
(Fig. 15).
The feathers of the tail are called _rectrices_, or "rudders," because
they are supposed to be used to steer, or direct the bird's course in
flying. But the tail is used also as a brake to check the speed in
alighting.
The tail is used more than any other organ to express the emotions. Some
birds, like the catbird and thrasher, keep it moving nearly all the
time, jerking it this way and that, and tossing it upward.
[Illustration: FIG. 16.
Tail of Sapsucker.]
In woodpeckers and swifts the tail feathers are not soft at the end like
others, but the stems or shafts project beyond the feathery part, and
are stiff like the tail of a sapsucker (Fig. 16) or sharp like this of
the chimney swift (Fig. 17). These birds use the tail as a prop to hold
them against the tree trunk or chimney wall, and to help them in
climbing.
[Illustration: FIG. 17.
Swift Tail.]
Tail feathers are not so strongly rooted as wing feathers, and are
easily pulled out. Sometimes, when a man or boy tries to catch a bird by
the tail, the bird will escape, leaving the tail in his hand.
XXVI
HIS DRESS
A BIRD'S whole dress is made of feathers, but the feathers are not all
alike. There are, indeed, several kinds of feathers, and four of them
are found on every bird. There are flight feathers, clothing feathers,
downy feathers, thread feathers, and powder-down feathers.
Feathers of all kinds are made in the same way. All have, first, a
quill, the horny part next to the body; second, a shaft, the white part
on which the barbs grow; third, the barbs, which grow out on each side
of the shaft, and together are called the vane; fourth, the barbules, or
little barbs, growing out of the barbs; and last, the barbicels, which
grow on the barbules, and on the wings have the tiny hooks which hold
them together.
But though feathers are made on the same pattern, they look very
different. The wing and tail feathers are stiff and strong, and are
called flight feathers, but those on the breast and body are called
soft, and cling closely to keep the bird warm and dry. These are called
the clothing feathers, because they clothe the bird.
Down feathers, which are almost always hidden under the clothing
feathers, are, like their name, downy, and answer to our under-clothes.
Thread feathers grow among the clothing feathers, and are almost like
hairs. It is these that the cook singes off the fowls.
Kingfishers who dive, and ducks who spend much time on the water, have
very thick down under the feathers--like suits of very warm
under-clothes--which keeps the water away from their bodies. Thus they
can dive, or sit on the water hours at a time, and not feel wet at all.
Powder-down feathers grow on some herons and cockatoos. They are called
by that name because the tip ends are continually breaking off like
white dust. Nobody knows their use.
Different from all these are the feathers called plumes, like the long,
soft ostrich plumes we all know; the dainty little ones that stand
straight up, and look as if the wind would blow them away; the long,
showy feathers that the peacock spreads with so much pride, or even the
pretty, drooping ones in the cock's tail.
These feathers are of no use for flight or for warmth, they rather
hinder than help. They are for ornament, and there are many kinds among
birds, all exquisitely beautiful. Nature has given to birds a more
wonderful dress than to any other living creature.
It is with his feathers that a bird expresses his feelings. In anger he
fluffs them out till he looks twice as big as usual; we have all seen a
hen bristle up when a dog comes near her brood.
Nervousness or excitement is shown by jerking the wings and tail, and if
a bird wishes to escape notice, he can make his plumage a perfect
disguise. Mr. Bolles's pet owl would stretch himself up long and slim,
with feathers hugging his body, when he looked so much like a broken
branch of a tree that Mr. Bolles could hardly see him. And another owl
that I heard of, when he was on the ground, would flatten himself and
spread his plumage around, so that the eye could scarcely separate him
from the dead leaves about him.
No one takes better care of his dress than a bird, and that is why it
looks well for a year. Every day, with most birds, it is washed and
carefully dried, each feather being passed through the bill, and the
whole thoroughly shaken out. At night one may often see robins and
catbirds before going to bed, dressing their plumage and shaking off the
day's dust.
Besides washing and drying the feathers, birds need oil to keep them in
best condition. For this purpose they have a little "oil jug," a small
gland over the tail, out of which, with the bill, they can squeeze a
drop of oil. We often see ducks and geese oiling their feathers before a
rain.
Water birds, who need a great deal of oil to keep out the wet, have the
oil jug very large.
Birds seem to know perfectly well the beauty of their plumage. Not only
do they try to show it off, as the peacock when he spreads his tail, but
they seem to feel shame when their feathers are injured or soiled. One
white feather coming in where it does not belong will make a bird very
unhappy. He will work and tug at it to pull it out, and often make
himself actually ill over the trouble. I had a captive bird who died, I
think, from worry and work over a wing feather which persisted in coming
in white, and which he insisted on pulling out every time.
XXVII
DIFFERENT COLORED SUITS
A BIRD does not always wear the same colored dress, as I said in the
chapter on moulting. A goldfinch, who through the summer wears a gay
yellow coat, comes out in the fall in plain olive and black; and the
scarlet tanager, who flourishes in the most brilliant red, changes to a
quiet green in winter. Besides these, some birds wear at one season a
spotted coat, and come out afterwards in one of plain colors.
Most of them change by moulting, as I explained, the old feathers
dropping out and new ones of another color coming in; or, to speak
exactly, the new ones growing out and pushing the old ones off on their
tips. But some change color without moulting. All birds moult completely
in the autumn, many moult partially in the spring, and some, as I said,
change without moulting.
This last change of color is made partly by fading, and partly by
breaking off the tips of the feathers, or what is called "abrasion."
This is a curious process. I told you something about it in chapter vii.
Certain feathers have edges different in color from the rest; as, for
example, a black feather with tips of yellow. While the feathers are new
and perfect, as they lie over each other like shingles on a roof, only
the edges show, and these being yellow, the bird appears to be dressed
in yellow. But the yellow tips are not so strong as the rest, and they
break or wear off, or are pulled off in the spring. What is strange,
they break exactly where the black begins. So as soon as the yellow is
off, the black shows, and behold, the yellow bird suddenly becomes a
black bird.
That is the way some birds manage to put on their spring dress in the
fall. The solid color is the color of the spring, but it is hidden or
veiled by tips of another color for winter.
The meadowlark changes in this way. In the winter his coat is brownish,
or buff. In the spring these tips are worn or broken off, and he comes
out in yellow and black.
Another change, even more curious, is made by some birds, who all winter
wear white spots, or light scolloped edges to their feathers, and in
spring the spots are gone.
In these, the white or light parts only break off, as sharply as if cut
with scissors. They leave the edges of the feathers notched in queer
ways, but as they lie over each other that does not show.
[Illustration: BLACK AND WHITE WARBLERS (MALE AND FEMALE)]
Birds in this way can change color without changing their feathers.
While moulting but once a year, they can show two suits, and by
partially moulting twice, can show three suits.
Another thing about the color of feathers is interesting. Some colors,
such as black, and red, and brown, are caused by coloring matter in the
feather. But other colors are only an effect of the way the feather is
made, whether it has ridges on it, or certain minute specks under the
surface, which seem to act as prisms (says Dr. Newton), and reflect the
light in different colors.
For instance, green is always due to some shade of yellow coloring
matter under a surface full of lengthwise ridges, and other colors are
made in similar ways.
These curious facts have been found out by that tell-tale little
instrument the microscope, and no doubt it will reveal many more secrets
in time.
Color is useful to birds, as well as beautiful. Its great use is to
conceal them from their enemies, and they show that they know this by
their conduct.
When a bird is of the color of dead leaves, or the sand, he has only
to flatten himself and keep still, and he is hidden. Such a bird on the
nest will often let one come close, and even stroke her, while relying
on her color to be unseen. A sitting ruffed grouse will do so. But if
snow falls, the same bird is very wild, for she knows she can be seen in
the snow.
I have seen a striped bird,--black and white warbler,--when frightened,
flatten himself on a branch, where he looked so much like the bark that
he could not be seen.
Ground birds are mostly in mottled colors of the ground. The
whip-poor-will, whose habit it is to rest on a log all day, wears colors
that hide him as well as if he were under the log.
The striking colors on a bird are often bidden when he is at rest, but
show plainly when he flies. When a flicker stands quietly on a fence he
is all in rather dull colors, but when he flies he shows a large
snow-white spot on his back, so that as far as one can see him he may be
known.
A meadowlark on the ground looks not unlike a flicker, but when he flies
he shows that the outside feathers of his tail are white. This is as
striking a mark as the white spot on the flicker.
Many birds have such markings, and it is thought by men who study birds
and look for a use in everything, that such marks serve the purpose of
"danger signals" or "recognition marks." That by these birds can know
each other in the dusk, or that the flash of color will catch the eye,
when the bird does not wish to give a call, but to slip away quietly to
avoid danger, and at the same time to give notice to other birds to do
the same.
HIS RELATIONS WITH US
XXVIII
HOW HE WORKS FOR US
MANY times in this book I have spoken of the great value of the services
of birds, in helping us destroy insects and weeds that injure our crops.
But there is more to be said about it.
From morning till night, almost the whole of his life, nearly every bird
is working for us. He does not know he is working for us, of course. He
is simply hunting for the food he likes, and what is good for young
birds to eat.
But what he chooses to eat himself, and to feed the young, consists
mostly of creatures that destroy our fruit and vegetables, caterpillars
that eat the leaves off our trees, worms that get into our apples and
berries, beetles that spoil our roses and our potatoes, mice that eat
our crops, and all the worms and grubs that gardeners and farmers are
all the time fighting.
As I have already said, some of the birds like cherries and green peas,
and other things we prefer to keep for ourselves. But we should never
forget that they have earned, by their work among the worms, all they
can take.
[Illustration: CEDAR-BIRD]
I say this, not merely because I love the birds, and want to have them
live and be happy, but because it is true. It has been proved true by
scientific men in the service of the United States government.
These men have had thousands of birds killed to see what they were
eating, and have found out that nearly all the birds they have
examined--blackbirds, cedar-birds, blue jays, hawks, owls, even
crows--do us more good by the injurious creatures they destroy, than
harm by the fruits and vegetables they eat. To this there is, among the
small birds, but one exception, the English sparrow, and, of the large
ones, only the two hawks and one owl, mentioned on page 53.
Chickadees like to eat the eggs of cankerworms; and for a single meal,
one of these tiny birds will eat two hundred and fifty eggs, and he will
take several meals a day. Now cankerworms destroy our apples. When they
get into an orchard in force, it looks, as Miss Merriam says, as if it
had been burned over.
Robins, catbirds, and shrikes, and several others, like to eat cutworms,
which destroy grass and other plants. As many as three hundred of them
have been found in the stomach of one robin, of course for one meal.
Ants are very troublesome in many ways, and three thousand of them have
been taken from the stomach of one flicker.
Rats and mice, ground squirrels and gophers, make great havoc in our
crops, and farmers spend much time and labor trying to get rid of them;
but these creatures are the favorite food of most hawks and owls.