Popular Science Monthly/Volume 26/February 1885/Why Birds Sing
By Dr. B. PLACZEK.
I HAVE long been an interested observer of bird-life. The situation of my house and garden, on the terrace-slopes of the Spielberg, affords me favorable opportunities for studying the habits of the feathered tribes. They build their nests in my garden, and lend themselves with great docility to the purposes of the friendly spectator of their movements. At one time the nest of a hedge-sparrow (Sylvia curruca) attracted my attention; I noticed particularly the increased care that was taken by the parent birds, as feeding-time approached, against unwelcome discovery. It was manifested, first, in a cessation of singing, and then in the combined efforts of the pair to divert strange looks from the nest. The birds, when about to take food to their young, were accustomed to fly down from opposite sides, and while one, after many cross-flights through the overhanging foliage, slipped into the nest, the other would flutter wildly hither and thither in another part of the tree. The three half-fledged young birds, when able to glide through the bushes, but not yet to fly, were dislodged from the nest, and while two of them disappeared with the mother, I caught the third, against the anxious remonstrances of the male, and hung it up in a cage in my veranda. The old male stood faithful to his chick, evidently concentrating his whole attention upon it, hopping around among the trees and collecting insects for it from early in the morning till the coming on of night, unceasingly, and never out of the neighborhood. He was accustomed to sound a grating zapp, zapp, in which the young one soon learned to join, in a variety of tones constituting a whole gamut of modulated sounds, from the note of cheerful pleasure to those of anxiety and anger, and was moved to utterance by the most insignificant event in the cage or around it.
I observed that the male bird, which had sung much less than usual while the female was sitting, and had ceased to sing entirely as soon as the young ones were hatched out, resumed his old habit of song as soon as the fledgeling's domicile was changed from the nest to the cage. He would execute a kind of strophe of from seven to nine clear, ringing notes, having sometimes a joyous and sometimes a melancholy expression. What was the meaning of the song which he thus resumed? Was it poured out to dispel the sorrow of the lonely orphaned young one? Did the absence of the female give the male a greater liberty in the matter? Or, was it sung in hopes of bringing the female back, or in rivalry with another male? Pondering over such questions as these led me to reflections and observations on the origin and meaning of the songs of birds.
While we may regard the ordinary vocal utterances of birds as expressions of their moods and wants, signals of intelligence, notes of warning, or calls for help, their song proper must be supposed to describe their more deep-felt emotions and anxieties, and to be related to their common expressions of sound as art is related to the handicrafts that minister to the necessities of life. Like art, the birdsong also, repeatedly exercised, may become an habitual mode of expression.
The majority of ornithologists agree in ascribing an erotic character to the songs of birds; not only the melting melodies, but also those of their tones that are discordant to the human car, are regarded as love-notes. Darwin finally, saving some reserves, came to accept this view. To be able to speak critically of the love-song, one should pay especial regard to the love-life of birds. It would be to throw water into the sea to add to what ornithological writers have advanced concerning the exceeding vital worth and cosmical significance of love. Nevertheless, I venture the opinion that the origin of the song-habit is to be found in other sources as well as in this important factor, among which is the joy of life, manifested in an irresistible determination to announce itself in melody; and that the song is more perfectly brought out in proportion as this feeling is more highly developed in the organization. Birds in freedom begin to sing long before pairing, and continue it, subject to interruptions, long afterward, though all passion has been extinguished; and domesticated birds sing through the whole year without regard to breeding-time, though no female or companion ever be in sight. Such birds, born in captivity, never feel the loss of freedom, and, if they are well taken care of, are always hearty and in good spirits. The bird sings, to a large extent, for his own pleasure; for he frequently lets himself out lustily when he knows he is all alone. In the spring-time of love, when all life is invigorated, and the effort to win a mate by ardent wooing is crowned with the joy of triumph, the song reaches its highest perfection. But the male bird also sings to entertain his mate during the arduous nest-building and hatching, to cheer the young, and, if he be a domesticated bird, to give pleasure to his lord and the providence that takes care of him, and in doing so to please himself. Lastly, the bird sings—by habit, as we call it—because the tendency is innate in the organs of song to exercise themselves.
My male hedge-sparrow, whose truly devoted care of its solitary young one I have described, began, after a ten days' pause, to sing more frequently and intensively, although neither a female nor a male of his species was in the neighborhood, apparently to cheer his ward. His evening farewells, uttered in a clear voice, were peculiarly expressive and touching. When, after eight days more, the chick began of itself to pick food from the dish and to snap at flies, the old bird discontinued its daytime feeding and singing, and came only at night. When the young bird was ready to fly, it came no more.
Female birds, as a rule, do not sing. The mechanism of their vocal apparatus is the same as that of the males, though with a weaker muscularity; and they are not wanting in ability to give melodious and vigorous expression to the exuberance of their life, but they seem to have lost the habit, or to be without the disposition to do so. Some authors, with Daines Barrington and Darwin, regard their non-inclination to sing as a mark of prudence; for it would be dangerous for them to make themselves conspicuous during the breeding-season, and direct the attention of enemies to their nests with their precious contents. But some other authors suggest, and I am inclined to agree with them, that they are restrained by a feminine reserve. The knowledge that the ardor of the male can be stimulated by indifference and inflamed to fury by resistance, prompts the female to practice all the arts of coquetry, of which Mantegazza says: "No woman can surpass the wonderful refinement with which a female canary-bird will offer a seeming of opposition to the passion of the male. All the numerous arts with which the world of women can conceal a 'yes' under a 'no' are as nothing compared with the arrant coquetry, the dissembled efforts to escape, the snappings and bitings, and the thousand tricks of the females of animals." Brehm says that the male finds in the female those desirable and attractive qualities that are wanting in himself. He seeks the opposite to himself with the force of a chemical element. A loud singing by the female would be as unpleasant to him as a beard on the face of a woman would be to a man. According to an Eastern proverb, man makes love with his speech, woman by her attitude and bearing. Among the feathered races, whose love-life is more largely and intensively developed than that of any other of the families of animals, the female perceives, feels, and knows that a discreet graciousness, a quiet power, and unobtrusive yet expressive, tender, and gentle manifestations, are attractions that operate irresistibly upon the male, and she therefore adopts them in her demeanor toward her suitor. Toussenel remarks: "Song is also given to the female; and, if she makes no use of the faculty, it is because she knows how to do more and better than to sing. She, as well as her brother, has gone through a course of music in her youth, and has cultivated her taste with the years. This cultivation, in fact, filled a need of both birds, for through it the female has become qualified to appreciate the charm of the elegies that are to be sighed out to her, and to award to the most worthy minstrel the prize for his song. The females know well enough how to express themselves in the language of passion when fancy inspires them to it or solitude condemns them to it." Fischer says that female birds begin at the same time with the males to twitter in the first practice of song, although they never pass beyond the stage of blundering at it. Bechstein remarks that the females of the canary bird, bull-finch, robin, and lark utter a melodious song, particularly in widowhood. Darwin suggests that in some of these cases of female songsters the habit of singing may be ascribed to the fact that the birds are so well cared for and are captive; for such conditions are most likely to disturb all the functions connected with reproduction. Numerous examples have been mentioned of the partial transmission of secondary characteristics of the male to the female; and it is not, therefore, very surprising to find that the females of a few species also possess a fully developed and active faculty of singing. I will only add to these facts that even for a repressed exercise, and with a restricted muscular activity, a force and a proper organ are requisite, and that therefore the gently modulated, muffled sounds, the peeping, whispering, clucking, smacking, and cooing, with which the females respond to the persuasions of the male, control their young, and otherwise express themselves, require a vocal apparatus similar to that of the male, which shall not be stunted by non-use. Instead of regarding, as Darwin did, the singing organs of female birds as an instance of the partial but useless transmission of secondary male characteristics to the female, I think we might now plausibly consider it a transmission in undiminished perfection of a faculty generally characteristic of both, but which is most freely exercised in the male on account of its relation to the most important act of his life, and hence to the maintenance of the species.
Singing out of rivalry finds an explanation in the disposition of the exultant songster to show himself off and to surpass others. If this exultant feeling is wanting, as, for instance, when it is depressed by some uncomfortable condition, the emulative singing stops. Hence, freshly-caught birds are songless in the cage, as are also males when several of them are confined together. In these cases the birds are pining for their lost freedom, or are suffering from the feeling of being crowded or hampered in their movements.
Domesticated birds sing also from a kind of gratitude to please their master, after they have discovered that he likes their songs, and the act produces in return a wholesome effect upon them. Under such influences, they sing all through the year, and more than they would do in freedom. I have had the opportunity of making a remarkable observation which shows that singing-birds desire the notice and applause of their attendant, and are affected by them. I had a yellow thrush (Turdus saxatilis), taken from the nest, which had become quite tame and confiding. Its cage hung behind the window-curtain of my study, and this adjoined my bedroom. I sometimes heard early in the morning a clear, melodious cock-crowing that seemed to come from a distant barn-yard. I thought of everything to which I might attribute it except my bird, which had never indulged in anything but the simplest song when I was present; but I soon found out his trick. Having risen early one morning and gone into the study while the bird's head was still hidden under his wing, I sat still in a farther corner of the room till matters began to get lively in the cage. Unobserved by my pet, I could see him through the folds of the curtain stretch out his wings and one foot, and plume himself. Then he found his voice and sounded out the cock-crow which I had heard so often from my bedroom without suspecting its real origin. Had I not seen the bird's mouth open and his throat vibrating, I should still have thought the sound came from a distance. Suddenly I stepped behind the curtain, when the bird, perceiving me, broke off at once in the midst of his crowing—a thing he had never done when I appeared as a witness to his ordinary singing—and fluttered timorously around as if he had done something wrong. I went out from the room and waited near, but the bird did not crow any more, nor again for two days afterward. Then he ventured upon a repetition of his exercise before anything had moved in his neighborhood. I opened the door in the midst of his practice and he stopped, and he never would crow when any one was present. There is nothing particularly remarkable in the crowing of itself, for many birds imitate the sounds made by other animals. The curious fact about this circumstance was, that the bird would not crow in my presence, and would always stop when any one appeared to witness his exercise. There is no evidence that he had ever had an unpleasant experience in connection with crowing. His conduct must therefore be attributed to a kind of feeling of shame, or to a sense of the unfitness of that method of expression to a bird of his character and standing. Have we not in this another proof of the possession by animals of a psychical quality which it has been usual to regard as peculiarly and distinctively human?—Translated for the Popular Science Monthly from Kosmos.