Chapter 11

When the birds are caught their heads should be snipped off as you do those of domestic fowls, or in some other way that is as painless as possible. According to this plan not so many birds can be secured, it is true, but it would be well to let the quail become more abundant in our country, for in certain seasons of the year they destroy certain kinds of insects that do much harm to the grain. Besides, they are such sweet and innocent birds that all of us like to see them scuttling along by the roadside, and listen to their musical calling in the clover fields--"Bob white! bob white!" Then, too, if they were allowed to become tame and plentiful, we might sometimes have the luxury of quail's eggs on our tables.

A BIRD'S EDUCATION*

*Reprinted by permission from "Forest and Stream."

So far as regards the recent discussion as to how animals learn, whether by instinct or instruction, my study of birds leads me to take a middle position; perhaps I would better say to take sides with both parties. Birds acquire knowledge partly by instinct and partly by tutelage, and the same is no doubt true of all other animals. This statement will be borne out by several concrete cases.

Some years ago I made a number of experiments in rearing young birds taken as early as possible from the nest. Among them were meadowlarks, red-winged blackbirds, brown thrashers, blue jays, wood thrushes, catbirds, flickers, red-headed woodpeckers, and several other species. Nearly all of them were secured some time before they were naturally ready to leave their natal places. Without any instruction from parents or older birds they soon left the nests I had improvised for them, hopped about on the cage floor for a while, and presently insisted on clambering upon the perches, to which they clung in the regulation way. Indeed, I noted again and again that the impulse to seek a perch was so strong that the young birds seemed to be moved to it by an imperative command. Nor were they long satisfied with a low perch, but instinctively mounted to the highest one they could find.

The same was true in regard to flight. No feathered adult was present to tutor them in the art of using their wings, yet they soon acquired that power of their own accord. It was inborn--the gift of flight. True, they were awkward at first, and gained skill only by degrees, but the original impulse was in their constitution. It is no doubt true that parent birds in the outdoors do give their young lessons in flight, but if the bantlings were left to themselves, they would acquire that art through their original endowment, although more slowly and with many more hard knocks.

As every one knows, juvenile birds at first open their mouths for their food. Proof may not be at hand for the opinion, but I am disposed to believe that they never need to be told by their parents to do that; their instincts prompt them. It must be so, I think, for to suppose that the bird baby only a day or two from the shell could understand a parental command to open its mouth would be to presume that it has the instinct to grasp the meaning of such a behest, and that is more difficult to believe than that Nature simply impels it to take its food by opening its mandibles.

Now, when the young birds are taken from the nest and reared by hand, they insist for a long time on being fed in the juvenile manner. However, by and by they begin of their own volition to pick up food after the manner of the adults. At first they are very clumsy about it, but they persevere until they acquire skill, and presently they refuse entirely to open their mandibles for food. Here again Nature is their sole guide. Without human or avian suggestion they also learn to drink in the well-known bird fashion; also to bathe, chirp, frolic, and do many other things. Who has ever seen a pet bird in drinking try to lap like a dog, or take in long draughts like a cow or a horse? No; Nature made them birds, and birds they will be. It is noticeable, too, that when birds begin to peck, or bathe, or seek a perch, they do not usually act as if they were deliberately planning to do so, nor as if they were carrying on some process of thought leading to choice, but rather as if they were impelled by Nature to do so.

The chirping of birds is mostly, if not wholly, a matter of inheritance. For instance, my little wood thrushes, as soon as they reached a sufficient age, called just like their relatives of the sylvan solitudes; my brown thrashers uttered the labial chirp of the species; my red-winged blackbird exclaimed "Chack! chack!" after the manner of his kind; my bluebirds expressed their feelings in the sad little purr of _Sialia sialis_; my flickers did not borrow the calls of the red-heads, but each clung to its own language; my catbirds mewed like poor pussy in trouble; and so on through the whole list. True, these pets may have heard their parents' calls before they were taken from the nest, but it is not at all likely that they would have remembered them, for at first they only "cheeped" after the manner of most bantlings, and only a good while afterward did they fall to using the adult chirp. Besides, while still in the nest, they must have heard many other bird calls; why did they not acquire them? Heredity has laid a strong hand upon birds, and has drawn sharp dividing lines among the various species.

Instinct also plays a large part in moving the bird to sing and to render the peculiar arias of its kind. For instance, a pet wood thrush of mine, secured at an early age and kept far away from all his kith of the wildwood, became a fine musician. And what do you suppose was the tune he executed? It was the sweet, dreamy, somewhat labored song of the wood thrush in his native wilds. He never sang any other tune. I think he sang it better than any wild thrush I have ever heard. It was louder, clearer, more full-toned, but the quality of voice and the technique were precisely the same. Who was his teacher? No one but Nature, heredity, instinct, whatever you choose to call it. There was no wild thrush within a half mile of his cage.

The case of a pet thrasher was almost as striking. It is true, he may have heard several of his kin singing about the premises during the first spring of his captivity, but it is not probable that he learned their melodies so early in life. As the next spring approached, he began to sing the very medleys that the wild thrashers sing with so much earnestness and skill, and this was long before any thrashers had come back from the South.

I must now describe several cases in which inherited instinct did not prove so true a teacher. A young robin was once given me by a friend, and was kept by myself and others until the following summer. Strange as it may seem, he never acquired the well-known robin carol. Sometimes there were vague hints of it in his vocal performances, but for the most part he whistled strains in a loud, shrill tone that no wild robin ever dreamed of inflicting on the world. They were more like crude human efforts at whistling than anything else. Indeed, I think they were picked up from the whistling he heard about the house. Some of his strains were very sweet, and all of them were wonderful for a bird. A friend played "Yankee Doodle" on a cornet, and Master 'Rastus--for that was his name--gave a very fair and funny imitation of part of the air. There were many robins caroling in the trees about the premises, and 'Rastus was often left out of doors among them, but he never acquired the red-breast minstrelsy.

A similar instance was that of a pet red-winged blackbird, which, instead of whistling the labored "Grook-o-lee" of his species, learned to mimic all kinds of sounds in and out of the house, among them the crowing of the cocks of the barnyard. These two instances would indicate that some birds must at least be associated with their kin in order to learn the songs of their species.

My comical pet blue jay gave proof of the need of parental training. While he intuitively called like a jay, he never was able to sing the sweet, gurgling roulade of the wild jays. On the contrary, he treated us to all kinds of odd, imitative, mirth-provoking performances that no self-respecting jay in the open would think of enacting. After several months of cage life he was given his liberty. Now, indeed, he showed his lack of jay bringing up, and how little, in some respects, mere instinct can be relied on. When evening came he perched on a limb of the maple tree before the house, in a place as exposed as he could well find, not knowing that there was more danger in an outdoor roost than in his shielding cage. I could not induce him to come down, nor could I climb out to the branch on which he sat, and so I was compelled to leave him out of doors.

The next morning he was safe, the screech owls of the neighborhood having overlooked him in some way. The next evening he went to roost in the same exposed place, and that was the last I ever saw of my beloved pet. He was undoubtedly killed and devoured by the owls. Had he been reared out of doors in the usual way, his parents would have taught him to find a roosting place that was secure from predatory foes. No one has ever seen a wild jay sleeping in an exposed place.

In her charming little book, "True Bird Stories," Mrs. Olive Thorne Miller says that she "once watched the doings in a crow nursery." I quote:

"The most important thing the elders had to do was to teach the youngsters how to fly, and every little while one or both of the parents would fly around the pasture, giving a peculiar call as they went. This call appeared to be an order to the little folks to follow, for all would start up and circle round for a minute or two, and then drop back to the fence or the ground to rest.

"Once, while I was watching them, this cry was given, and all flew as usual except one bob-tailed baby, who stood on a big stone in the middle of the field. He was perhaps so comfortable that he did not want to go, or it may be he was afraid, and thought mamma would not notice him. But mothers' eyes are sharp, and she did see him. She knew, too, that baby crows must learn to fly; so when all came down again she flew right at the naughty bird, and knocked him off his perch. He squawked, and fluttered his wings to keep from falling, but the blow came so suddenly that he had not time to save himself, and he fell flat on the ground. In a minute he clambered back upon his stone, and I watched him closely. The next time the call came to fly he did not linger, but went with the rest, and so long as I could watch him he never disobeyed again."

This is evidence not only of parental teaching, but also of parental discipline. Here is another bit from the same volume, bearing its lesson on its face. "A lady told me a funny story about a robin. He was brought up in the house from the nest, and never learned to sing the robin song, for he had not heard it. He plainly tried to make some sort of music, and one of the family taught him to whistle 'Yankee Doodle'. He whistled it perfectly, and never tried to sing anything else. Once this Yankee Doodle robin got out of the house and flew up into a tree. When the wild birds came about him he entertained them by whistling his favorite air, which sent the birds off in a panic."

Do not the facts recited in this sketch prove that birds know and acquire some things through the promptings of instinct, while other things they can learn only by avian teaching?

My notes on instinct and education in bird song correspond with the conviction expressed by Dr. W. H. Hudson on page 257 of his interesting book entitled "The Naturalist in La Plata," fourth edition, 1903: "It is true that Daines Barrington's notion that young song birds learn to sing only by imitating the adults, still holds its ground; and Darwin gives it his approval in his 'Descent of Man'. It is perhaps one of those doctrines which are partly true, or which do not contain the whole truth; and it is possible to believe that, while many singing birds do so learn their songs, or acquire a greater proficiency in them from hearing the adults, in other species the song comes instinctively, and is, like other instincts and habits, purely an 'inherited memory'." What Dr. Hudson surmises may be the case, I believe my experiments have proved to be true.

ARE BIRDS SINGERS OR WHISTLERS?*

*Reprinted by permission from "Our Animal Friends."

Not a little discussion has arisen among the dissectors as to the anatomy of bird song. Into this controversy I shall not enter--at least, not in a controversial spirit--but shall recount only what may be regarded as the best and latest results of scientific research. How does a bird produce the melodious notes that emanate from his throat? Are they manufactured far down in the trachea, or only at its anterior opening? Are they voice tones or flute tones? These questions will be answered as we proceed to examine the bird's lyrical apparatus without going into wearisome detail, or making use of many difficult scientific terms, which are the bane of the general reader.

Let me begin at the upper end of the avian singing machine--that is, with the mouth, including the bill, the lips of which are called mandibles. Just as the movements of the human lips have much to do with the modifications of the human voice, so the opening and closing of the bird's mandibles exercise a modifying influence upon avicular tones. If it were not so, the feathered minstrel would not keep his mandibles in such constant motion during his lyrical recitals. You will notice that whenever he desires to strike a very high and loud note he opens his mandibles quite widely, sometimes almost to the fullest possible extent.

However, the expansion and contraction of the throat orifice, no doubt, produce still more marked variations in the tones of the vocalist; yet it must be borne in mind that closed or partly closed mandibles will obstruct the passage of the air from the throat, while open mandibles will permit of a full passage of the air current, and the tones will vary accordingly. Besides, the roof of the bird's mouth is grooved or convex, and therefore the character of the sounds will be somewhat dependent upon the position and movement of the upper mandible.

And then there is the bird's tongue, which is constantly in motion while the musical rehearsal is going on. Throughout its entire length it can be raised and lowered at the bird's will, or be made to quiver and roll, and by this means the air column forced up from the lungs is manipulated in a wonderful way, producing in some cases an almost unlimited variety of modulation.

Within the bird's neck two elastic tubes run down from the mouth into the chest. One of them is the gullet or aesophagus, which is the channel through which the bird's food descends into the crop and gizzard. The other little cylinder lies in front of the gullet, and is called the windpipe or trachea, and reaches down to the lungs, which are the bellows furnishing the wind for the avian pipe organ. As Dr. Coues says, the trachea is "composed of a series of very numerous gristly or bony rings connected together by an elastic membrane," and is supplied with an intricate set of muscles by which it can be shortened or elongated at the will of the songster himself.

Now let us look at the upper end of this wonderful pneumatic pipe, which so often throws Pan and all his coterie into a transport when the thrasher and the wood thrush flute their dithyrambs. Here we find the larynx. It is simply the anterior specialized portion of the trachea, located at the base of the tongue, and in mammals is honored as the voice organ, whereas in birds it is distinguished as the fluting apparatus, the instrument that really produces the varied vocalization of the bird realm. But the music is not the product of vocal cords, as is the case in the human larynx, for at the upper end of the avian larynx there is a slit or fissure, somewhat elliptical in form, and set in the fork of the hyoid bone, which constitutes the bifurcated root of the tongue. This fissure is called the glottis. At the bird's fiat, it can be opened and closed and made to assume a great variety of forms. Moreover, just in front of it there is a fold of mucous membrane called the epiglottis, which is in reality a tiny trapdoor closing over the opening when necessity requires. When the bird swallows food or drink, this little flap shuts down, and prevents the entrance of any clogging substance into the windpipe to choke the feathered diner.

We have now come to the most strategic point in our investigation of the anatomy of bird song, for in the avian world a special distinction has been conferred upon that little orifice in the bird's throat called the glottis. It is here that all the music, as well as all other so-called vocal sounds, are generated--they are simply piped or fluted through a slit, so that birds are _whistlers_, not singers or vocalists. I repeat, so that my meaning may be perfectly clear--bird music is not produced by means of vocal cords, as is the music of the human throat, but by means of a whistling aperture in the larynx. And that wonderful cleft has been placed there for that specific purpose. Properly speaking, therefore, the feathered choralist does not have a voice, but only a wind instrument; albeit a marvelous contrivance it is.

It will be easy now to see how the bird's tones are capable of a large variety of modulations. The glottis is controlled by a system of muscles that are perfectly obedient, within their limits, to the bird's volitions, and thus it may be made to assume a great number of different forms, each giving expression to a different vocal effect. The shape of the glottis is also modified in numerous ways by the movement of the tongue and mandibles. Nor is that all, for the air column pumped up from the lungs may be increased or diminished at will, a very strong current producing a loud tone, and a feeble current a low one. The elongation or contraction of the whole throat will also modify the pneumatic column, and thereby alter the quality of the tones.

We may go still further in our analysis. Suppose a bird should open his mouth and throat as widely as possible, hold all his lyrical organs steady, and blow his windpipe with all the strength his lungs could command, it is obvious that the effect would be a clear, loud, uniform whistle, such as the meadowlark sends across the green fields. But suppose he desires to "blow a dreamy hautbois note, slender and refined as ever stirred the air of Arcady or trembled in the vineyards of old Provence," then all the musician in plumes needs to do is to contract the slit in his throat, depress his tongue, almost close his mandibles, and simply allow a slender air current to sift from the lungs through the syrinx and out of the glottis. What if the whim should seize him to pipe a trill or a quaver to the water witches of the meadow, as Master Song Sparrow so often chooses to do? Then he simply needs to set his tongue and throat to quivering, and you have his enrapturing tremolo. Beautiful, is it not?

There are birds that send a kind of guttural sound from their throats, such as the cuckoos and occasionally the blue jays. Notice the cuckoo as he utters his call, which every swain interprets as the harbinger of a coming shower, and you will observe that his throat bulges out like that of a croaking frog, and quivers at the same time in a convulsed way. It is plain that the air about to be forced from the glottis is flung back by some muscular action and set to vibrating in the laryngean cavity, thus giving the sound its croaking quality when the elastic current is finally released.

Now, if the reader will pucker up his lips and whistle a tune, he will notice that the sound is actually produced at the small labial orifice and nowhere else; however, the tones are modified and modulated at will in a variety of ways--by a deft, though almost imperceptible, manipulation of the tongue, by a slight enlargement or contraction of the aperture, and especially by a dexterous control of the air column blown from the lungs. Just so the lyrists of fields and woods pipe their roundels and _chansons_ through the chink in their throats, save that in the bird's case the mouth and tongue are anterior to the whistling aperture. I know a young man who has trained himself so as to be able to mimic to perfection the complex songs of the western meadowlark and the cardinal grosbeak. He does it by whistling.

Near the lower end of the trachea, just above the lungs, there is a specialized organ of the bird's throat called the syrinx. It is a cylinder formed of bony rings, provided with a mesh of muscles, and having membranous folds which act as valves upon the two orifices of the _bronchi_ leading to the lungs. Many scientific gentlemen have declared that the syrinx is the voice organ of the birds, the elastic margins of the folds or valves being set to vibrating by the projection of the air from the lungs, and thus producing the varied lays we hear in the outdoor concert. However, Mr. Maurice Thompson--who, by the way, found time to do something else besides writing "Alice of Old Vincennes," and something just as creditable to his talent, too--dissected many birds with special reference to this subject, and gave close attention to birds in the act of singing, both out of doors and in captivity, and I am convinced that he proved the theory of the syringeal origin of bird song to be an erroneous one.

Only two reasons need be adduced for this conclusion. First, it is unreasonable to suppose that the rich, loud, clear notes of the thrasher, the cardinal, and the mockingbird, lilting across the fields and capable of being heard a long distance, are generated far down in the lyrist's chest by the vibrating of the margin of a tiny mucous membrane. If it had its genesis there, it surely would display a muffled or guttural or sepulchral quality. In the second place, it has been proved by actual dissection that the shrike, which possesses no song gift worthy of the name, has a well-developed syrinx, while the mockingbird, our feathered minstrel _par excellence_, has a syrinx that is absolutely insignificant. On the other hand, the shrike's larynx, including the glottis, is a clumsy affair, whereas the mocker's larynx is indeed wonderfully made.

It must not be supposed, however, that the syrinx does not perform an important function in the production of avian melody. It acts as a regulator or meter of the air impelled from the lungs. By means of the folds or membranous valves the mouths of the bronchial tubes may be opened widely or almost closed, and in this way, to quote from Mr. Thompson, "the bird is enabled to measure in the nicest manner the amount of air thrown from the lungs into the trachea." In producing a staccato, for example, the valves flop up and down, doling out the air at the proper intervals and in precisely the right quantities.

Indeed, nothing in the world of Nature is more wonderful than the gift of bird song, and nothing proves more clearly the doctrine of design, or, at least, of adaptation to a specialized purpose.

BIRD FLIGHT*

*Reprinted by permission from "The Evening Post," New York.