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:
". . . . Clamorem ad sidera tollunt
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.
