The parrot is perhaps possessed of the greatest vocal power of any other bird. He imitates almost the entire range of sounds that are uttered by all other birds combined, and can also imitate the sounds of human speech from the highest to the lowest pitch of the human voice. In addition to all this, he imitates many noises, such as the sounds of sawing wood, the slam of a door, and the whistling of the wind. The vocal range of the parrot is perhaps the most marvellous of all the vocal products of the animal kingdom. One strange thing, however, that I observe among them is, that the range of sounds that they use among themselves is very small. I have made some records of parrots, macaws, cockatoos, &c., and I find their natural vocal sounds usually wanting in quality: most of their sounds are hoarse and guttural.
Among the gallinaceous birds there does not appear to be much music. There is a great sameness of sounds in the different species, and they seem to be confined to the economic use of speech.
In my early life I devoted much time to gunning, and I observed then, and called attention to the fact, that when a covey of birds became scattered I could tell at what point they would huddle. I could tell this by the call of one bird and the reply of the others. The call-bird, which was always the leader of the covey, would sound his call from a certain point near which the other birds would usually assemble, and during this time they would answer him from various other points. The sound used by the call-bird is unlike that used by the rest of the flock, but the sounds with which they reply to him are all alike, and by observing this I could always find the covey again by allowing them time to come together, especially if it was late in the afternoon.
Mr. Wood, of Washington, D.C., has given such attention to the sounds of birds that he can interpret and imitate nearly all the sounds made by domestic birds, and many of those made by wild birds. He has twice confused and arrested the flight of an army of crows by imitating the calls of their leader. His feats have been witnessed with astonishment by many men of science.
SOUNDS OF FISHES
Among fishes I have found but few sounds, and most of these I have never heard except when the fish was taken out of the water. The carp and high-fin, however, I have frequently heard while in the water. It has occurred to me that the sound is not the medium of communication, but it is the result of an action by which they do communicate even when the sound is not audible. I have observed while holding the fish in my hand when he makes this sound that it produces a jarring sensation which is very perceptible. It is quite possible that in his natural element these powerful vibrations are imparted to the surrounding water, and through it communicated to another fish, who feels it in his sensitive body instead of hearing it as sound. It may be accompanied by the sound merely resulting from the force applied, but not in itself constituting any part of the means of communication. It is not unlike what we call sound, in the fact that it is generated in the same way, transmitted in the same way, and received in the same way as sound. When I have time and opportunity I shall carry my studies of the language of fishes much farther. Their means of communication are very contracted, but it is superfluous for me to say that they have such means.
Many observations have already been made on the language of insects, and much diversity of opinion prevails. Very little has been said about the details of their intercourse, but the consensus of opinion is that they must in some way communicate among themselves. To me they seem to live within a world of their own, as other classes of the animal kingdom do. The means of communication used by mammals could not be available among aquatic forms, any more than could their modes of locomotion. Each different class of the animal kingdom is endowed with such characters and faculties as best adapt them to the sphere in which they live; and the mode of communication best fitted to the conditions of insect life would be as little suited to mammals, perhaps, as the feathers of a bird would be for locomotion in the realm of fishes.
LANGUAGE OF INSECTS
I am aware that some high authorities have claimed that insects communicate by sounds. My own opinion is that they employ a system of grating or scratching by means of their stigmata, but that the sound created thus performs no function in the act of communicating, but is only a bi-product, so to speak, and that the jarring sensation transmitted through the air is the real means by which they understand each other, possibly somewhat like telegraphy, in which the sounds are not modulated, but are distinguished by their duration and the interval between them. I do not announce this as conclusive, but merely suggest it as a possible key to their mode of intercourse.
A COLONY OF ANTS