Popular Science Monthly/Volume 9/June 1876/Natural Trumpet of the Crane
|NATURAL TRUMPET OF THE CRANE.|
SPORTSMEN and naturalists, both at home and abroad, would do well to collect not only the skins of birds, but also to search for any peculiarity which may happen to occur in their internal structure, especially the bones and the larynx.
Some weeks since, when calling upon my friend Mr. Jamrach, the animal-dealer, I observed in the back-yard, on the dust-heap, a number of dead birds. Among them was the body of a very large crane. Mr. Jamrach allowed me to take this home, and I made several preparations of it. We now figure the very remarkable trachea, or wind-pipe, of this bird. In an ordinary bird, such as a chicken, when cutting open the skin of the throat, it will be found that the trachea forms a continuous tube, going in a direct line from the mouth to the lungs, where it bifurcates. In the crane this is not the case. Instead of passing between the two bones ordinarily known as the merry-thought, it becomes convoluted in a very remarkable manner. If this convolution had been placed immediately under the skin, first of all it would have been cumbersome to the bird; and, secondly, there would have been a great likelihood of its becoming injured. The breastbone, therefore, has been hollowed out in the middle in such a manner as to keep the trachea packed up in a beautiful box of bone. Inside this box of bone there are about thirteen inches of the trachea. The trachea enters this bony box at its lowest margin; it then runs along the bottom and ascends to the top; then takes a very sharp turn, and again descending to the bottom of the box joins the lungs in the usual way. In life this trachea is not fixed in the box, but is capable of extension and prolongation; in fact, is almost as elastic as India-rubber.
The diagram will explain this.
The curious cartilaginous-like material—reminding us of mosaic work—of which the trachea is composed, differs much in pattern in its various portions, the rings being single near the mouth, while a few inches farther they appear to be double. A model of them at this part of the tube can be obtained by locking the fingers of both hands one into the other. Just as the trachea leaves the bony box it is considerably enlarged.
T is the tongue, attached to the bifurcated hyoid bone; LA is the larynx; TR is the trachea immediately before it buries itself in the peculiar hollow box of bone, A. In this box, as already described, it becomes convoluted; then, leaving the box, it enters the cavity of the chest, and joins the lungs at L.
Of course, the use of this curious structure is to produce those wonderful sounds which are peculiar to the crane. In fact, it is a portion of a cornet-à-piston or trombone, and is, no doubt, worked by some very delicate muscles. I have never had the pleasure of seeing cranes fly in the air, but I am told that the noise they make is very wonderful. We read: "Cranes range, according to the season, from the north of Europe to the south of Asia, and north of Africa, and in the latter country they are said to extend their migrations as far as the Cape of Good Hope. On these excursions they fly high in the air, though they experience some difficulty in getting on the wing from the ground. Before taking their spring they run some paces, raise themselves a little at first, and then unfold a powerful and rapid wing. In the air they form very nearly an isosceles triangle, possibly for the purpose of cutting the element with greater facility. When attacked by an eagle, or the wind is likely to break their order, they close in circles. Their passage frequently takes place during the night, which is known by their sonorous voice, which announces it; and the head of the troop often utters, to indicate the route he is taking, a cry of appeal to which all his followers answer. Their voices, even on these nocturnal voyages, are exceedingly loud—probably owing to the length of the windpipe and the convolution near its bronchial extremity. When they cry during the day they are generally understood to forebode rain, as is the case with the cries of many other birds which feed partially on those worms which the approaching humidity brings to the surface—not only when the rain actually falls, but when, from the changed state of the air, the evaporation is much diminished. When they are peculiarly noisy and tumultuous, and fly near the ground, occasionally alighting, it is considered as a pretty certain indication of a tempest. On the other hand, when they rise high, and fly onward in regular order, it is regarded as a sign of fine weather."
That great observer, Virgil, has used the simile of cranes in flight in a grand passage in the tenth "Æneid," to give an idea of the Greeks and Trojans charging each other in the battle-field:
Dardanidæ e muris: spes addita suscitat iras:
Tela manu jaciunt. Quales sub nubibus atris
Strymoniæ dant signa grues atque æthera tranant
Cum sonitu, fugiuntque Notos clamore secundo."
[The Trojans, from their walls, raise acclamations to the stars. Additional hope rouses up their fury. Darts from their hands they hurl, as under the black lowering clouds Strymonian cranes give the signal and swim along the skies with obstreperous din, and from the stormy south winds with joyous clamor fly.]
I consider the marvelous natural trumpet of the crane to be a most beautiful provision given by the Creator to these wild birds to enable them to keep their ranks, and not lose each other when migrating. In fact, we men have adopted the idea by using trumpets. It often happens that the dust at a field-day is so great that very little can be seen, while it would be impossible for the human voice to be heard; trumpets, therefore, come in here of the greatest service, especially to direct movements of cavalry. In the same way, the cranes might possibly lose each other when flying in the wilderness of space of the vast firmament of ether, and, were it not for their being able to signal to each other, they would be unable to travel with facility either at night, or when passing through clouds and fogs.
A few days since a valued correspondent in Ireland sent us the breastbone of a Hooper swan. I have dissected this, and find the trachea convoluted in a manner very similar to that of the crane.
There is a legend that when a swan is dying he becomes musical. The origin of this legend probably is the trumpeting of the wild-swan. This our friends can hear in the Zoölogical Gardens; it is a melancholy-sound, and may be thus written—"hwoo hwoo." The tame swan has not this structure of the windpipe, showing, therefore, that it is a distinct species. As the trumpet is useful to the crane, so also is it to the swan. They fly very high, in order that the "hawks should not gain the sky" of them; they always fly with the wind, and when going with a stiff breeze are said to go at a pace of a hundred miles an hour.
Many of our friends have probably heard that amusing bird, the trumpeter (Cariama cristata). Mr. Cholmondeley, of Condover, has a very tame specimen, that wanders all over his house, and goes out walking in the garden with him. In the trumpeter-bird there is a musical apparatus of another kind. The note of the trumpeter is very agreeable to the ear.
I have lately dissected a Merganser. I find that his trachea is also peculiar: it swells out considerably about the third of its way down, and at the end it bulges out into a box as large as a walnut. The common duck has a curious larynx. At the bottom of the windpipe will be found a bony dilatation. Our readers should examine this for themselves. The female has not this peculiarity, and, strange to say, although the drake has this very peculiar organism, he is not able to quack—the females only quack; the males give a short hiss. My friend Mr. Bartlett informs me that on one occasion a gentleman sent him this bony box, which the cook had taken out, and said that it was the ossified heart of a duck.—Land and Water.