BIRDS
SUGGESTIONS.—The domestic pigeon, the fowl, and the English sparrow
are most commonly within the reach of students. The last bird has
become a pest and is almost the only bird whose destruction is
desirable. The female is somewhat uniformly mottled with gray and
brown in fine markings. The male has a black throat with the other
markings of black, brown, and white, in stronger contrast than the
marking of the female. As the different species of birds are
essentially alike in structural features, the directions and questions
may be used with any bird at hand. When studying feathers, one or more
should be provided for each pupil in the class. The feet and the bills
of birds should be kept for study.
[Illustration]
Does the =body of the bird= like the toad and the turtle, have a head, a
trunk, a tail, and two pairs of limbs? Do the fore and hind limbs differ
from each other more or less than the limbs of other backboned animals?
Does any other vertebrate use them for purposes as widely different?
=Eye.=—Does the _eyeball_ have parts corresponding to the eyeball of a
fish or a frog; viz., cornea, iris, pupil? Which is more movable, the
upper or the lower _eyelid_? _Are_ there any lashes? The bird (like what
other animal?) has a third eyelid, or nictitating membrane. Compare its
thickness with that of the other lids. Is it drawn over the eyeball from
the inner or the outer corner of the eye? Can you see in the human eye
any wrinkle or growth which might be regarded as remains, or vestige, of
such a membrane?
How many =nostrils=? In which mandible are they located? Are they nearer
the tip or the base of the mandible? (Fig. 284.) What is their shape? Do
the nasal passages go directly down through the mandible or do they go
backward? Is the inner nasal opening into the mouth or into the throat?
[Illustration:
FIG. 284.—SKULL OF DOMESTIC FOWL.
_q_, quadrate (“four-sided”) bone by which lower jaw is attached to
skull (wanting in beasts, present in reptiles; see Fig. 277).
]
The beak or =bill= consists of the upper and lower mandibles. The
outside of the beak seems to be of what kind of material? Examine the
decapitated head of a fowl or of a dissected bird, and find if there is
a covering on the bill which can be cut or scraped off. Is the mass of
the bill of bony or horny material? With what part of the human head are
the mandibles homologous? (Fig. 284.)
=Ears.=—Do birds have external ears? Is there an _external opening_
leading to the ear? In searching for it, blow or push forward the
feathers. If found, notice its location, size, shape, and what surrounds
the opening. There is an owl spoken of as the long-eared owl. Are its
ears long?
The =leg= has three divisions: the uppermost is the _thigh_ (called the
“second joint” in a fowl); the middle division is the _shank_ (or
“drumstick”); and the lowest, which is the slender bone covered with
scales, is formed by the union of the _ankle_ and the _instep_. (The
bones of the three divisions are named femur, tibiotarsus, and
tarsometatarsus.) The _foot_ consists entirely of toes, the bones of
which are called phalanges. Is there a bone in each claw? (See Fig.
285.) Supply the numerals in this sentence: The pigeon has ____ toes,
the hind toe having ____ joints; of the three front toes, the inner has
____ joints (count the claw as one joint), the middle has ____ joints,
and the outer toe has ____ joints (Fig. 285). Is the thigh of a bird
bare or feathered? The shin? The ankle? Where is the ankle joint of a
bird? Do you see the remains of another bone (the splint bone, or
fibula) on the shin bone of the shank? (Fig. 285 or 286.) Why would
several joints in the ankle be a disadvantage to a bird?
[Illustration:
FIG. 285.—LEG BONES OF BIRD.
]
[Illustration:
FIG. 286.—SKELETON OF BIRD.
_Rh_, vertebræ; _Cl_, clavicle; _Co_, coracoid; _Sc_, scapula; _St_,
sternum; _H_, humerus; _R_, radius; _U_, ulna; _P_, thumb; _Fe_,
femur; _T_, tibia. See Fig. 394.
=Questions=: Which is the stiffest portion of the vertebral column?
How are the ribs braced against each other? Which is longer, thigh
bone or shin? Compare shoulder blade with man’s (Fig. 399). Which is
the extra shoulder bone? Compare tail vertebræ with those of extinct
bird, Fig. 290.
]
The _thigh_ hardly projects beyond the skin of the trunk, as may be
noticed in a plucked fowl. The thigh extends forward from the hip joint
(Figs. 286, 299) in order to bring the point of support forward under
the centre of weight. Why are long front toes more necessary than long
hind toes? As the bird must often bring its head to the ground, the hip
joints are near the dorsal surface and the body swings between the two
points of support somewhat like a silver ice pitcher on its two pivots.
Hence stooping, which makes a man so unsteady, does not cause a bird to
lose steadiness.
[Illustration:
FIG. 287.—HAND AND WRIST OF FOWL (after Parker).
_DG._ 1–3, digits; _MC._ 1–3, metacarpals; _CC._ 3, wrist.
]
The =wing= has three divisions which correspond to the upper arm, the
forearm, and the hand of man (Fig. 286). When the wing is folded, the
three divisions lie close alongside one another. Fold your arm in the
same manner. The similarity of the bones of the first and second
divisions to the bones of our upper _arm_ and _forearm_ is very obvious
(Fig. 286). Explain. The _hand_ of a bird is furnished with only three
digits (Fig. 287). The three palm bones (metacarpals) are firmly united
(Fig. 287). This gives firmness to the stroke in flying.
[Illustration:
FIG. 288.—HAND, WRIST (_c_), FOREARM, AND ELBOW OF YOUNG CHICK (after
Parker).
]
That the bird is _descended from animals_ which had the fingers and palm
bones less firmly united is shown by comparing the hands of a _chick_
and of an _adult_ fowl (Figs. 287, 288). The wrist also solidifies with
age, the five carpals of the chick being reduced to two in the fowl
(Figs. 287, 288). The thumb or first digit has a covering of skin
separate from that of the other digits, as may be seen in a plucked
bird. The degenerate hand of the fowl is of course useless as a hand
(what serves in its place?) but it is well fitted for firm support of
the feathers in flying. The two bones of the forearm are also firmly
joined. There are eighteen movable joints in our arm and hand. The bird
has only the three joints which enable it to fold its wing. The wrist
joint is the joint in the forward angle of the wing.
[Illustration:
FIG. 289.—BREASTBONE AND SHOULDER BONES OF CASSOWARY.
]
[Illustration:
FIG. 290.—A FOSSIL BIRD (_archæopteryx_) found in the rocks of a
former geological epoch.
=Question=: Find two resemblances to reptiles in this extinct bird
absent from skeletons of extant birds.
]
Since the fore limbs are taken up with locomotion, the =grasping
function= has been assumed by the _jaws_. How does their shape adapt
them to this use? For the same reason the _neck_ of a bird surpasses the
necks of all other animals in what respect? Is the trunk of a bird
flexible or inflexible? There is thus a _correlation_ between structure
of neck and trunk. Explain. The same correlation is found in which of
the reptiles? (Why does rigidity of trunk require flexibility of neck?)
Why does the length of neck in birds correlate with the length of legs?
Examples? (See Figs. 314, 315, 332.) Exceptions? (Fig. 324.) Why does a
swan or a goose have a long neck, though its legs are short?
[Illustration:
FIG. 291.—QUILL FEATHER.
_D_, downy portion.
]
To make a firm support for the wings the vertebræ of the back are
immovably joined, also there are three bones in each shoulder, the
collar bone, the shoulder blade, and the coracoid bone (Fig. 286). The
collar bones are united (why?) and form the “wishbone” or “pulling
bone.” To furnish surface for the attachment of the large flying muscles
there is a prominent ridge or keel on the breastbone (Fig. 286). It is
lacking in most birds which do not fly (Fig. 289).
The =feathers= are perhaps the most characteristic feature of birds. The
large feathers of the wings and tail are called _quill feathers_. A
quill feather (Fig. 291) is seen to consist of two parts, the _shaft_,
or supporting axis, and the broad _vane_ or web. What part of the shaft
is round? Hollow? Solid? Is the shaft straight? Are the sides of the
vane usually equal in width? Can you tell by looking at a quill whether
it belongs to the wing or the tail, and which wing or which side of the
tail it comes from? Do the quills overlap with the wide side of the vane
above or beneath the next feather? Can you cause two parts of the vane
to unite again by pressing together the two sides of a split in the
vane? Does the web separate at the same place when pulled until it
splits again?
[Illustration:
FIG. 292.—I, CONTOUR FEATHER. II, III, PARTS OF QUILL FEATHER,
enlarged.
]
The hollow part of the shaft of a quill feather is called the _quill_.
The part of the shaft bearing the vane is called the _rachis_ (rā-kis).
The vane consists of slender _barbs_ which are branches of the shaft
(II, Fig. 292). As the name indicates (see dictionary), a barb resembles
a hair. The barbs in turn bear secondary branches called _barbules_, and
these again have shorter branches called _barbicels_ (III, Fig. 292).
These are sometimes bent in the form of hooklets (Fig. 292, III), and
the hooklets of neighbouring barbules interlock, giving firmness to the
vane. When two barbules are split apart, and then reunited by stroking
the vane between the thumb and the finger, the union may be so strong
that a pull upon the vane will cause it to split in a new place next
time.
[Illustration:
FIG. 293.—A DOWN FEATHER, enlarged.
]
There are =four kinds= of feathers, (1) the _quill_ feathers, just
studied; (2) the _contour_ feathers (I, Fig. 292), which form the
general surface of the body and give it its outlines; (3) the _downy_
feathers (Fig. 293), abundant on nestlings and found among the contour
feathers of the adult but not showing on the surface; (4) the _pin_
feathers, which are hair-like, and which are removed from a plucked bird
by singeing. The contour feathers are similar in structure to the quill
feathers. They protect the body from blows, overlap so as to shed the
rain, and, with the aid of the downy feathers, retain the heat, thus
accounting for the high temperature of the bird. The downy feathers are
soft and fluffy, as they possess few or no barbicels; sometimes they
lack the rachis (Fig. 293). The pin feathers are delicate horny shafts,
greatly resembling hairs, but they may have a tuft of barbs at the ends.
[Illustration:
FIG. 294.—DORSAL AND VENTRAL VIEW OF PLUCKED BIRD, showing regions
where feathers grow.
]
A =feather grows= from a small projection (or papilla) found at the
bottom of a depression of the skin. The quill is formed by being moulded
around the papilla. Do you see any opening at the tip of the quill for
blood vessels to enter and nourish the feather? What is in the quill?
(Fig. 291.) The rachis? A young contour or quill feather is inclosed in
a delicate sheath which is cast off when the feather has been formed.
Have you seen the sheath incasing a young feather in a moulting bird?
There are considerable =areas= or tracts on a bird’s skin =without
contour feathers=. Such bare tracts are found along the ridge of the
breast and on the sides of the neck. However, the contour feathers lie
so as to overlap and cover the whole body perfectly (Fig. 294).
[Illustration:
FIG. 295.—WING OF BIRD.
_1_, false quills (on thumb); _2_, primaries; _3_, secondaries;
tertiaries (dark) are one above another at right; _a_, _b_, coverts.
]
The shedding of the feathers is called =moulting=. Feathers, like the
leaves of trees, are delicate structures and lose perfect condition with
age. Hence the annual renewal of the feathers is an advantage. Most
birds shed twice a year, and with many the summer plumage is brighter
coloured than the winter plumage. When a feather is shed on one side,
the corresponding feather on the other side is always shed with it.
(What need for this?) A large _oil gland_ is easily found on the dorsal
side of the tail. How does the bird apply the oil to the feathers?
[Illustration:
FIG. 296.
_A_, point dividing primaries from secondaries; _B_, coverts.
]
[Illustration:
FIG. 297.—CEDAR WAXWING, with regions of body marked.
_S_, forehead; _Sc_, crown (with crest); _Hh_, nape; _K_, throat;
_Br_, breast; _Ba_, lower parts; _R_, back; _Rt_, tail; _B_, tail
coverts; _P_, shoulder feathers (scapulars); _T_, wing coverts;
_HS_, primaries; _AS_, secondaries; _Al_, thumb feathers.
]
In describing and classifying birds, it is necessary to know the names
of the various external =regions= of the body and plumage. These may be
learned by studying Figs. 295, 296, 297, 298. The quills on the hand are
called primaries, those on the forearm are the secondaries, those on the
upper arm are the tertiaries. Those on the tail are called the _tail
quills_. The feathers at the base of the quills are called the
_coverts_. The thumb bears one or more quills called the spurious
quills. Is the wing concave on the lower or the upper side? Of what
advantage is this when the bird is at rest? When it is flying?
[Illustration:
FIG. 298.—PLAN OF BIRD.
_s_, centre of gravity.
]
[Illustration:
FIG. 299.—POSITION OF LIMBS OF PIGEON.
]
=Control of Flight.=—Did you ever see a bird sitting on a swinging limb?
What was its chief means of balancing itself? When flying, what does a
bird do to direct its course upward? Downward? Is the body level when it
turns to either side? Birds with long, pointed wings excel in what
respect? Examples? Birds with great wing surface excel in what kind of
flight? Examples. Name a common bird with short wings which has a
laboured, whirring flight. Is its tail large or small? Does it avoid
obstacles and direct its flight well? Why or why not? When a boat is to
be turned to the right, must the rudder be pulled to the right or to the
left? (The rudder drags in the water and thus pulls the boat around.)
When the bird wishes to go upward, must its tail be turned up or down?
How when it wishes to go down? When a buzzard soars for an hour without
flapping its wings, does it move at a uniform rate? For what does it use
the momentum gained when going with the wind?
[Illustration:
FIG. 300.
_a_, clambering foot of chimney sweep; _b_, climbing foot of
woodpecker; _c_, perching foot of thrush; _d_, seizing foot of hawk;
_e_, scratching foot of pheasant; _f_, stalking foot of kingfisher;
_g_, running foot of ostrich; _h_, wading foot of heron; _i_,
paddling foot of gull; _k_, swimming foot of duck; _l_, steering
foot of cormorant; _m_, diving foot of grebe; _n_, skimming foot of
coot. =Question=: Does any bird use its foot as a hand? (Fig. 320.)
]
=Flying.=—When studying the quill feathers of the wing, you saw that the
wider side of the vane is beneath the feather next behind it. During the
downward stroke of the wing this side of the vane is pressed by the air
against the feather above it and the air cannot pass through the wing.
As the wing is raised the vanes separate and the air passes through. The
convex upper surface of the wing also prevents the wing from catching
air as it is raised. Spread a wing and blow strongly against its lower
surface; its upper surface. What effects are noticed?
Study the =scales= on the leg of a bird (Fig. 300). Why is the leg scaly
rather than feathered from the ankle downward? Which scales are largest?
(Fig. 300.) How do the scales on the front and the back differ? What can
you say of the scales at the bottom of the foot; at the joints of the
toes? Explain. How does the covering of the nails and the bill compare
in colour, texture, hardness, and firmness of attachment with the scales
of the leg?
[Illustration:
FIG. 301.—AN ALTRICAL BIRD, _i.e._ poorly developed at hatching. Young
pigeon, naked, beak too weak for eating.
]
=Draw= an outline of the bird seen from the side. Make drawings of the
head and the feet more detailed and on a larger scale.
[Illustration:
FIG. 302.—A PRECOCIAL BIRD (well developed at hatching). Feathered,
able to run and to pick up food. Precocity is a sign of instinctive
life and low intelligence. A baby is not precocious.
=Question=: Is pigeon or fowl exposed to more dangers in infancy?
]
Why does a goose have more feathers suitable for making pillows than has
a fowl? In what country did the domestic fowl originate? (Encyclopædia.)
Why does a cock crow for dawn? (Consider animal life in jungle.)
=Activities of a Bird.=—Observe a bird _eating_. Does it seem to chew or
break its food before swallowing? Does it have to lift its head in order
to swallow food? To swallow drink? Why is there a difference? After
feeding the bird, can you feel the food in the crop, or enlargement of
the gullet at the base of the neck? (Fig. 304.)
Feel and look for any movements in _breathing_. Can you find how often
it breathes per minute? Place hand under the bird’s wing. What do you
think of its _temperature_; or better, what temperature is shown by a
thermometer held under its wing? Do you see any connection between the
breathing rate and the temperature? Test (as with the crayfish) whether
a bird can _see_ behind its head. Notice the movements of the
nictitating membrane. Does it appear to be transparent?
Watch a bird _fly_ around a closed room and review the questions on
Control of Flight.
_Bend_ a bird’s leg and see if it has any effect upon its toes. Notice a
bird (especially a large fowl) walk, to see if it bends its toes as the
foot is lifted. Pull the rear tendon in a foot cut from a fowl for the
kitchen. Does the bird have to use muscular exertion to _grasp_ a stick
upon which it sits? Why, or why not? When is this bending of the toes by
bending the legs of special advantage to a hawk? To a duck? To a wading
bird? Why is a fowl safe from a hawk if it stands close to a tree?
[Illustration:
FIG 303.—HEAD OF WOODPECKER.
_c_, tongue; _a_, _b_, _d_, hyoid bone; _e_, _q_, windpipe; _f_,
salivary gland.
]
Do you see any signs of teeth in the bird’s jaws? Why are duck’s “teeth”
(so called by children) not teeth? Can the tongue of a bird be pulled
forward? (Fig. 303.) What is its shape? If there is opportunity, dissect
and study the slender, bony (hyoid) apparatus to which the base of the
tongue is attached (Fig. 303), the opening of the windpipe, or trachea,
the slitlike opening of windpipe, which is so narrow as to prevent food
falling into the windpipe.
[Illustration:
FIG. 304.—ANATOMY OF DOVE × ½.
_bk_, keel of breastbone; _G_, _g_, brain; _lr_, windpipe; _lu_, lung;
_h_, heart; _sr_, gullet; _k_, crop; _dr_, glandular stomach; _mm_,
gizzard; _d_, intestine; _n_, kidney; _hl_, ureter; _eil_, openings
of ureter and egg duct into cloaca, _kl_.
]
[Illustration:
FIG. 305.—FOOD TUBE OF BIRD.
_P_, pancreas; _C_, cæca.
=Question=: Identify each part by means of Fig. 304.
]
=The Internal Organs, or Viscera= (Figs. 304 and 305).—The viscera
(vis’se-ra), as in most vertebrates, _include_ the food tube and its
glands; the lungs, the heart, and the larger blood vessels; the kidneys
and bladder and the reproductive organs. The lower part, or gullet, is
enlarged into a _crop_. It is largest in grain-eating birds. It is found
in the V-shaped depression at the angle of the wishbone, just before the
food tube enters the thorax. The food is stored and softened in the
crop. From the crop the food passes at intervals into the glandular
stomach. Close to this is the muscular stomach, or gizzard. Are the
places of entrance and exit on opposite sides of the gizzard, or near
together? (Fig. 304.) Is the lining of the gizzard rough or smooth? Why?
Is the gizzard tough or weak? Why are small stones in the gizzard? Why
do not hawks and other birds of prey need a muscular gizzard? The liver
and pancreas empty their secretions into the intestines by several ducts
a little way beyond the gizzard. Beyond the mouths of two cæca (Fig.
305) the many-coiled intestine empties into the straight rectum, which
terminates in a widened part called the cloaca. Not only the intestine,
but the two ureters of the urinary system and the two genital ducts of
the reproductive system all empty into the cloaca (Figs. 304, 305).
[Illustration:
FIG. 306.—POSITION OF LUNGS AND AIR SACS (Pigeon).
_Tr_, windpipe; _P_, lungs; _Lm_, sac under clavicle with prolongation
(_Lh_) into humerus; _La_, sacs in abdomen.
]
The =lungs= have their rear surfaces attached to the spinal column and
ribs (_lu_, Fig. 304). They are connected with thin-walled, transparent
_air sacs_ which aid in purifying the blood. When inflated with warm
air, they probably make the body of the bird more buoyant. For the
names, location, and shape of several pairs of air sacs, see Fig. 306.
The connection of the air sacs with hollows in the humerus bones is also
shown in the figure. Many of the _bones are hollow_; this adds to the
buoyancy of the bird. The pulmonary artery, as in man, takes dark blood
to the lungs to exchange its carbon dioxide for oxygen. Of two animals
of the same weight, which expends more energy, the one that flies, or
the one that runs the same distance? Does a bird require more oxygen or
less, in proportion to its weight, than an animal that lives on the
ground? Are the vocal chords of a bird higher or lower in the windpipe
than those of a man? (Fig. 307.)
[Illustration:
FIG. 307.—POSITION OF VOCAL CORDS (_str_) OF MAMMAL AND BIRD.
=Question=: Does a fowl ever croak after its head and part of its neck
are cut off? Explain.
]
The heart of a bird, like a man’s heart, has four chambers; hence it
keeps the purified blood separate from the impure blood. Since pure
blood reaches the organs of a bird, oxidation is more perfect than in
the body of any animals yet studied. Birds have higher temperature than
any other class of animals whatsoever. Tell how the jaws, the tail, and
the wings of the fossil bird Archæopteryx differed from living birds
(Fig. 290).
SUGGESTIONS.—In the field work, besides seeking the answers to
definite questions, pupils may be required to hand in a record of the
places and the times of seeing a certain number of birds (20–40) with
the actions and features which made each distinguishable. Also, and
more important, each pupil should hand in a record of a careful and
thorough outdoor study of one common species (see below) as regards
habits, nesting, relation to environment, etc.
FIELD STUDY OF A COMMON SPECIES.—(_For written report._) Name of
species. _Haunts._ Method of locomotion when not flying. _Flying_
(rate, sailing, accompanying sound if any, soaring).
What is the _food_? How obtained? _Association_ with birds of its own
species. _Relation_ to birds of other species.
Where does it build its _nest_? Why is such a situation selected? Of
what is the nest built? How is the material carried, and how built
into the nest? Does the bird’s body fill the nest?
Describe the _eggs_. Does the male bird ever sit or otherwise assist
female before hatching? Does it assist after hatching? How long is
taken to lay a sitting of eggs? How long before the birds are hatched?
_When hatched_ are they helpless? Blind? Feathered? (Figs. 301, 302.)
Do the nestlings require much food? How many times in an hour is food
brought? How distributed? Even if the old birds sometimes eat fruit do
they take fruit to the young? What do they feed to the young? How long
before they leave the nest? Do the parents try to teach them to fly?
Do the parents care for them after the nest is left? What songs or
calls has the bird?
[Illustration:
FIG. 308.—EUROPEAN TOMTIT’S NEST.
What are the advantages of its shape?
]
[Illustration:
FIG. 309.—TAILOR BIRD’S NEST (India).
Instinct for nest building highly perfected.
]
=General Field Study.=—(_For written report._) Name the best and poorest
flyers you know; birds that fly most of the time; birds that seldom fly.
Observe birds that pair; live in flocks. Does their sociability vary
with the season? Do you ever see birds quarrelling? Fighting? What birds
do you observe whipping or driving birds larger than themselves? Which
parent do young birds most resemble? Name the purposes for which birds
sing. Which senses are very acute? Why? Dull? Why? Can you test your
statements by experiment? A partridge usually sits with 18 to 24 eggs in
nest. About how long after laying first egg before sitting begins? Do
several partridge hens lay in the same nest?
[Illustration:
FIG. 310.—HOUSE WREN.
]
_Haunts._—Name some birds that are found most often in the following
localities: about our homes, in gardens and orchards, fields and
meadows, in bushes, in the woods, in secluded woods, around streams of
water, in thickets, in pine woods.
_Size._—Name birds as large as a robin or larger, nearly as large, half
as large, much smaller.
_Colours._—Which sex is more brilliant? Of what advantage are bright
colours to one sex? Of what advantage are dull colours to the other sex?
Which have yellow breasts, red patch on heads, red or chestnut breasts,
blue backs, black all over?
_Habits._—Name the birds that walk, jump, swim, live in flocks, sing
while flying, fly in undulations, in circles, have laboured flight.
=Economic Importance of Birds.=—Farmers find their most valuable allies
in the class _aves_, as birds are the deadliest enemies of insects and
gnawing animals. To the innumerable robbers which devastate our fields
and gardens, nature opposes the army of birds. They are less numerous
than insects and other robbers, it is true, but they are skilful and
zealous in pursuit, keen of eye, quick, active, and remarkably
voracious. The purely insectivorous birds are the most useful, but the
omnivorous and graminivorous birds do not disdain insects. _The perchers
and the woodpeckers should be protected most carefully._ The night birds
of prey (and those of the day to a less degree) are very destructive to
field mice, rabbits, and other gnawing animals. Some ignorant farmers
complain continually about the harm done by birds. To destroy them is as
unwise as it would be to destroy the skin which protects the human body
because it has a spot upon it! It cannot be repeated too plainly that to
hunt useful birds is a wrong and mischievous act, and it is stupid and
barbarous to destroy their nests.
[Illustration:
FIG. 311.—SCREECH OWL (_Megascops asio_).
=Question=: Compare posture of body, position of eyes, and size of
eyes, with other birds.
]
[Illustration:
FIG. 312.—GOSHAWK, or chicken hawk.
]
Injurious birds are few. Of course birds which are the enemies of other
birds are enemies of mankind, but examples are scarce (some owls and
hawks). Many birds of prey are classed thus by mistake. Sparrow-hawks,
for instance, do not eat birds except in rare instances; they feed
chiefly upon insects. A sparrow hawk often keeps watch over a field
where grasshoppers are plentiful and destroys great numbers of them.
When a bird is killed because it is supposed to be injurious, the crop
should always be examined, and its contents will often surprise those
who are sure it is a harmful bird. The writer once found two frogs,
three grasshoppers, and five beetles that had been swallowed by a
“chicken hawk” killed by an irate farmer, but no sign of birds having
been used for food. Fowls should not be raised in open places, but among
trees and bushes, where hawks cannot swoop. Birds which live exclusively
upon fish are, of course, opposed to human interests. Pigeons are
destructive to grain; eagles feed chiefly upon other birds.
[Illustration:
FIG. 313.—ROAD RUNNER, or chaparral bird (Tex. to Cal.). What order?
(Key, p. 177.)
]
If the birds eat the grapes, do not kill the birds, but plant more
grapes. People with two or three fruit trees or a small garden are the
only ones that lose a noticeable amount of food. We cut down the forests
from which the birds obtain part of their food. We destroy insect pests
at great cost of spraying, etc. The commission the birds charge for such
work is very small indeed. (See pages 177–183.)
[Illustration:
FIG. 314.—WOOD DUCK, male (_Aix sponsa_). Nests in hollow trees
throughout North America. Also called summer duck in South. Why?
]
The =English sparrow= is one bird of which no good word may be said.
Among birds, it holds the place held by rats among beasts. It is crafty,
quarrelsome, thieving, and a nuisance. It was imported in 1852 to eat
moths. The results show how ignorant we are of animal life, and how slow
we should be to tamper with the arrangements of nature. In Southern
cities it produces five or six broods each year with four to six young
in each brood. (Notice what it feeds its young.) It fights, competes
with and drives away our native useful birds. It also eats grain and
preys upon gardens. They have multiplied more in Australia and in North
America than in Europe, because they left behind them their native
enemies and their new enemies (crows, jays, shrikes, etc.) have not yet
developed, to a sufficient extent, the habit of preying upon them.
Nature will, perhaps, after a long time, restore the equilibrium
destroyed by presumptuous man.
=Protection of Birds.=—1. Leave as many trees and bushes standing as
possible. Plant trees, encourage bushes.
2. Do not keep a cat. A mouse trap is more useful than a cat. A tax
should be imposed upon owners of cats.
3. Make a bird house and place it on a pole; remove bark from pole that
cats may not climb it; or put a broad band of tin around the pole.
4. Scatter food in winter. In dry regions and in hot weather keep a
shallow tin vessel containing water on the roof of an outhouse, or in an
out-of-the-way place, for shy birds.
5. Do not wear feathers obtained by the killing of birds. What feathers
are not so obtained?
6. Report all violators of laws for protection of birds.
7. Destroy English sparrows.
[Illustration:
FIG. 315.—GREAT BLUE HERON. In flight, balancing with legs.
]
=Migration.=—Many birds, in fact most birds, migrate to warmer climates
to spend the winter. Naturalists were once content to speak of the
migration of birds as a wonderful instinct, and made no attempt to
explain it. As birds have the warmest covering of all animals, the
winter migration is not for the purpose of escaping the cold; it is
probably to escape starvation, because in cold countries food is largely
hidden by snow in winter. On the other hand, if the birds remained in
the warm countries in summer, the food found in northern countries in
summer would be unused, while they would have to compete with the
numerous tropical birds for food, and they and their eggs would be in
danger from snakes, wild cats, and other beasts of prey so numerous in
warm climates. These are the best reasons so far given for migration.
[Illustration:
FIG. 316.—EUROPEAN SWALLOWS (_Hirundo urbica_), assembling for autumn
flight to South.
]
The =manner= and =methods of migration= have been studied more carefully
in Europe than in America. Migration is not a blind, infallible
instinct, but the route is learned and taught by the old birds to the
young ones; they go in flocks to keep from losing the way (Fig. 316);
the oldest and strongest birds guide the flocks (Fig. 317). The birds
which lose their way are young ones of the last brood, or mothers that
turn aside to look for their strayed young. The adult males seldom lose
their way unless scattered by a storm. Birds are sometimes caught in
storms or join flocks of another species and arrive in countries
unsuited for them, and perish. For example, a sea or marsh bird would
die of hunger on arriving in a very dry country.
The =landmarks of the route= are mountains, rivers, valleys, and coast
lines. This knowledge is handed down from one generation to another. It
includes the location of certain places on the route where food is
plentiful and the birds can rest in security. Siebohm and others have
studied the routes of migration in the Old World. The route from the
nesting places in northern Europe to Africa follows the Rhine, the Lake
of Geneva, the Rhone, whence some species follow the Italian and others
the Spanish coast line to Africa. Birds choose the lowest mountain
passes. The Old World martin travels every year from the North Cape to
the Cape of Good Hope and back again! Another route has been traced from
Egypt along the coast of Asia Minor, the Black Sea and Ural Mts. to
Siberia.
[Illustration:
FIG. 317.—CRANES MIGRATING, with leader at point of V-shaped line.
]
=Field Study of Migration.=—Three columns may be filled on the
blackboard in an unused corner, several months in spring or fall being
taken for the work. _First_ column, birds that stay all the year.
_Second_ column, birds that come from the south and are seen in summer
only. _Third_ column, birds that come from the north and are seen in
winter only. Exact dates of arrival and departure and flight overhead
should be recorded in notebooks. Many such records will enable American
zoologists to trace the migration routes of our birds.
[Illustration:
FIG. 318.—APTERYX, of New Zealand. Size of a hen, wings and tail
rudimentary, feathers hair-like.
]
=Moulting.=—How do birds arrange their feathers after they have been
ruffled? Do they ever bathe in water? In dust? Dust helps to remove old
oil. At what season have birds the brightest feathers? Why? Have you
ever seen evidence of the moulting of birds? Describe the moulting
process (page 120).
[Illustration:
FIG. 319.—GOLDEN, SILVER, AND NOBLE PHEASANTS, males. Order? (Key, p.
177.) Ornaments of males, brightest in season of courtship, are due
to sexual selection (Figs. 321–7–9, 333).
]
[Illustration:
FIG. 320. COCKATOO.
]
[Illustration:
FIG. 321.—BIRD OF PARADISE (Asia).
]
=Adaptations for Flying.=—Flight is the most difficult and
energy-consuming method of moving found among animals, and careful
adjustment is necessary. For balancing, the heaviest muscles are placed
at the lower and central portion of the body. These are the flying
muscles, and in some birds (humming birds) they make half of the entire
weight. Teeth are the densest of animal structures; teeth and the strong
chewing muscles required would make the head heavy and balancing
difficult; hence the chewing apparatus is transferred to the heavy
gizzard near the centre of gravity of the body. The bird’s neck is long
and excels all other necks in flexibility, but it is very slender
(although apparently heavy), being inclosed in a loose, feathered skin.
A cone is the best shape to enable the body to penetrate the air, and a
small neck would destroy the conical form. The internal organs are
compactly arranged and rest in the cavity of the breast bone. The
bellowslike air sacs filled with warm air lighten the bird’s weight. The
bones are hollow and very thin. The large tail quills are used by the
bird only in guiding its flight up and down, or balancing on a limb. The
feet also aid a flying bird in balancing. The wing is so constructed as
to present to the air a remarkably large surface compared with the small
bony support in the wing skeleton. Are tubes ever resorted to by human
architects when lightness combined with strength is desired? Which
quills in the wing serve to lengthen it? (Fig. 296.) To broaden it? Is
flight more difficult for a bird or for a butterfly? Which of them do
the flying machines more closely resemble? Can any bird fly for a long
time without flapping its wings?
[Illustration:
FIG. 322.—HERRING GULL. (Order?)
]
=Exercise in the Use of the Key.=—Copy this list and write the name of
the order to which each of the birds belongs. (Key, page 177.)
Cockatoo (Fig. 320)
Sacred Ibis (Fig. 328)
Screech Owl (Fig. 311)
Nightingale (Fig. 325)
Top-knot Quail (Fig. 329)
Wren (Fig. 310)
Apteryx (Fig. 318)
Lyre bird (Fig. 327)
Road Runner (Fig. 313)
Ostrich (Fig. 332)
Penguin (Fig. 330)
Pheasant (Fig. 319)
Wood Duck (Fig. 314)
Jacana (Fig. 324)
Sea Gull (Fig. 322)
Heron (Fig. 315)
Hawk (Fig. 312)
KEY, OR TABLE, FOR CLASSIFYING BIRDS (_Class Aves_) INTO ORDERS
ORDERS
A_{1} =Wings not suited for flight=, 2 or 3 toes RUNNERS
A_{2} =Wings suited for flight= (except the penguin)
B_{1} _Toes united by a web for swimming, legs short_
C_{1} Feet placed far back; wings short, tip not DIVERS
reaching to base of tail (Fig. 300)
C_{2} Bill flattened, horny plates under margin of BILL-STRAINERS
upper bill (Fig. 323)
C_{3} Wings long and pointed, bill slender SEA-FLIERS
C_{4} All four toes webbed, bare sac under GORGERS
throat
B_{2} _Toes not united by web for swimming_
C_{1} Three front toes, neck and legs long, tibia WADERS
(shin, or “drumstick”) partly bare
C_{2} Three front toes, neck and legs not long
D_{1} Claws short and blunt (e, Fig. 300)
E_{1} Feet and beak stout, young feathered, base SCRATCHERS
of hind toe elevated
E_{2} Feet and beak weak, young naked MESSENGERS
D_{2} Claws long, curved and sharp, bill hooked and ROBBERS
sharp
D_{3} Claws long, slightly curved, bill nearly PERCHERS
straight
C_{3} Two front and two hind toes (Fig. 300)
D_{1} Bill straight, feet used for climbing FOOT-CLIMBERS
D^1 Bill hooked, both bill and feet used for BILL-CLIMBERS
climbing
=The Food of Birds.=—Extracts from Bulletin No. 54 (United States Dept.
of Agriculture), by F. E. L. Beal.
[Illustration:
FIG. 323.—HEAD OF DUCK.
]
The practical value of birds in controlling insect pests should be
more generally recognized. It may be an easy matter to exterminate the
birds in an orchard or grain field, but it is an extremely difficult
one to control the insect pests. It is certain, too, that the value of
our native sparrows as weed destroyers is not appreciated. Weed seed
forms an important item of the winter food of many of these birds, and
it is impossible to estimate the immense numbers of noxious weeds
which are thus annually destroyed. If crows or blackbirds are seen in
numbers about cornfields, or if woodpeckers are noticed at work in an
orchard, it is perhaps not surprising that they are accused of doing
harm. Careful investigation, however, often shows that they are
actually destroying noxious insects; and also that even those which do
harm at one season may compensate for it by eating insect pests at
another. Insects are eaten at all times by the majority of land birds.
During the breeding season most kinds subsist largely on this food,
and rear their young exclusively upon it.
[Illustration:
FIG. 324.—JACANA. (Mexico, Southwest Texas, and Florida.)
=Questions=: What appears to be the use of such long toes? What
peculiarity of wing? head?
]
=Partridges.=—Speaking of 13 birds which he shot, Dr. Judd says: These
13 had taken weed seed to the extent of 63 per cent of their food.
Thirty-eight per cent was ragweed, 2 per cent tick trefoil, partridge
pea, and locust seeds, and 23 per cent seeds of miscellaneous weeds.
About 14 per cent of the quail’s food for the year consists of animal
matter (insects and their allies). Prominent among these are the
Colorado potato beetle, the striped squash beetle, the
cottonboll-weevil, grasshoppers. As a weed destroyer the quail has
few, if any, superiors. Moreover, its habits are such that it is
almost constantly on the ground, where it is brought in close contact
with both weed seeds and ground-living insects. It is a good ranger,
and, if undisturbed, will patrol every day all the fields in its
vicinity as it searches for food.
[Illustration:
FIG. 325.—NIGHTINGALE, × ⅓.
]
[Illustration:
FIG. 326.—SKYLARK, × ⅓.
]
Two celebrated European songsters.
=Doves=.—The food of the dove consists of seeds of weeds, together
with some grain. The examination of the contents of 237 stomachs shows
that over 99 per cent of the food consists wholly of vegetable matter.
=Cuckoos.=—An examination of the stomachs of 46 black-billed cuckoos,
taken during the summer months, showed the remains of 906
caterpillars, 44 beetles, 96 grasshoppers, 100 sawflies, 30 stink
bugs, and 15 spiders. Of the yellow-billed cuckoos, or “rain-crow,”
109 stomachs collected from May to October, inclusive, were examined.
The contents consisted of 1,865 caterpillars, 93 beetles, 242
grasshoppers, 37 sawflies, 69 bugs, 6 flies, and 86 spiders.
[Illustration:
FIG. 327.—LYRE BIRD, male.
]
=Woodpeckers.=—Careful observers have noticed that, excepting a single
species, these birds rarely leave any conspicuous mark on a healthy
tree, except when it is affected by wood-boring larvæ, which are
accurately located, dislodged, and devoured by the woodpecker. Of the
flickers’ or yellow-hammers’ stomachs examined, three were completely
filled with ants. Two of the birds each contained more than 3,000
ants, while the third bird contained fully 5,000. These ants belong to
species which live in the ground. It is these insects for which the
flicker is reaching when it runs about in the grass. The
yellow-bellied woodpecker or sapsucker (_Sphyrapicus varius_) was
shown to be guilty of pecking holes in the bark of various forest
trees, and sometimes in that of apple trees, and of drinking the sap
when the pits became filled. It has been proved, however, that besides
taking the sap the bird captures large numbers of insects which are
attracted by the sweet fluid, and that these form a very considerable
portion of its diet. The woodpeckers seem the only agents which can
successfully cope with certain insect enemies of the forests, and, to
some extent, with those of fruit trees also. For this reason, if for
no other, they should be protected in every possible way.
[Illustration:
FIG. 328.—SACRED IBIS. (Order?)
]
=The night hawk, or “bull bat,”= may be seen most often soaring high
in air in the afternoon or early evening. It nests upon rocks or bare
knolls and flat city roofs. Its food consists of insects taken on the
wing; and so greedy is the bird that when food is plentiful, it fills
its stomach almost to bursting. Ants (except workers) have wings and
fly as they are preparing to propagate. In destroying ants night hawks
rank next to, or even with, the woodpeckers, the acknowledged
ant-eaters among birds.
[Illustration:
FIG. 329.—TOP-KNOT QUAIL, or California Partridge. (West Texas to
California.)
]
=The kingbird, or martin=, is largely insectivorous. In an examination
of 62 stomachs of this bird, great care was taken to identify every
insect or fragment that had any resemblance to a honeybee; as a
result, 30 honeybees were identified, of which 29 were males or drones
and 1 was a worker.
=Blue Jay.=—In an investigation of the food of the blue jay 300
stomachs were examined, which showed that animal matter comprised 24
per cent and vegetable matter 76 per cent of the bird’s diet. The
jay’s favourite food is mast (_i.e._ acorns, chestnuts, chinquapins,
etc.), which was found in 200 of the 300 stomachs, and amounted to
more than 42 per cent of the whole food.
[Illustration:
FIG. 330.—PENGUIN OF PATAGONIA. Wings used as flippers for swimming.
]
=Crow.=—That he does pull up sprouting corn, destroy chickens, and rob
the nests of small birds has been repeatedly proved. Nor are these all
of his sins. He is known to eat frogs, toads, salamanders, and some
small snakes, all harmless creatures that do some good by eating
insects. Experience has shown that they may be prevented from pulling
up young corn by tarring the seed, which not only saves the corn but
forces them to turn their attention to insects. May beetles,
“dorbugs,” or June bugs, and others of the same family constitute the
principal food during spring and early summer, and are fed to the
young in immense quantities.
=Ricebird.=—The annual loss to rice growers on account of bobolinks
has been estimated at $2,000,000.
[Illustration:
FIG. 331.—Umbrella holding the nests of social weaver bird of Africa;
polygamous.
]
=Meadow Lark.=—Next to grasshoppers, beetles make up the most
important item of the meadow lark’s food, amounting to nearly 21 per
cent. May is the month when the dreaded cut-worm begins its deadly
career, and then the lark does some of its best work. Most of these
caterpillars are ground feeders, and are overlooked by birds which
habitually frequent trees, but the meadow lark finds and devours them
by thousands.
=Sparrows.=—Examination of many stomachs shows that in winter the tree
sparrow feeds entirely upon seeds of weeds. Probably each bird
consumes about one fourth of an ounce a day. Farther south the tree
sparrow is replaced in winter by the white-throated sparrow, the
white-crowned sparrow, the fox sparrow, the song sparrow, the field
sparrow, and several others; so that all over the land a vast number
of these seed eaters are at work during the colder months reducing
next year’s crop of worse than useless plants.
[Illustration:
FIG. 332.—AFRICAN OSTRICH, × ¹⁄₂₀. (order?)
]
=Robin.=—An examination of 500 stomachs shows that over 42 per cent of
its food is animal matter, principally insects, while the remainder is
made up largely of small fruits or berries. Vegetable food forms
nearly 58 per cent of the stomach contents, over 47 per cent being
wild fruits, and only a little more than 4 per cent being possibly
cultivated varieties. Cultivated fruit amounting to about 25 per cent
was found in the stomachs in June and July, but only a trifle in
August. Wild fruit, on the contrary, is eaten in every month, and
constitutes during half the year a staple food.
=Questions.=—Which of these birds are common in your neighbourhood?
Which of them according to the foregoing report are plainly injurious?
Clearly beneficial? Doubtful? Which are great destroyers of weed
seeds? Wood-borers? Ants? Grain? Why is the destruction of an ant by a
night hawk of greater benefit than the destruction of an ant by a
woodpecker? Name the only woodpecker that injures trees. If a bird
eats two ounces of grain and one ounce of insects, has it probably
done more good or more evil?